Fragment.java revision 352cc98b4621b76959af8f8a698fd75c6d6132e8
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.app;
18
19import android.animation.Animator;
20import android.content.ComponentCallbacks;
21import android.content.Context;
22import android.content.Intent;
23import android.content.res.Configuration;
24import android.content.res.Resources;
25import android.os.Bundle;
26import android.os.Parcel;
27import android.os.Parcelable;
28import android.util.AndroidRuntimeException;
29import android.util.AttributeSet;
30import android.util.DebugUtils;
31import android.util.SparseArray;
32import android.view.ContextMenu;
33import android.view.LayoutInflater;
34import android.view.Menu;
35import android.view.MenuInflater;
36import android.view.MenuItem;
37import android.view.View;
38import android.view.ViewGroup;
39import android.view.ContextMenu.ContextMenuInfo;
40import android.view.View.OnCreateContextMenuListener;
41import android.widget.AdapterView;
42
43import java.io.FileDescriptor;
44import java.io.PrintWriter;
45import java.util.HashMap;
46
47final class FragmentState implements Parcelable {
48    final String mClassName;
49    final int mIndex;
50    final boolean mFromLayout;
51    final int mFragmentId;
52    final int mContainerId;
53    final String mTag;
54    final boolean mRetainInstance;
55    final Bundle mArguments;
56
57    Bundle mSavedFragmentState;
58
59    Fragment mInstance;
60
61    public FragmentState(Fragment frag) {
62        mClassName = frag.getClass().getName();
63        mIndex = frag.mIndex;
64        mFromLayout = frag.mFromLayout;
65        mFragmentId = frag.mFragmentId;
66        mContainerId = frag.mContainerId;
67        mTag = frag.mTag;
68        mRetainInstance = frag.mRetainInstance;
69        mArguments = frag.mArguments;
70    }
71
72    public FragmentState(Parcel in) {
73        mClassName = in.readString();
74        mIndex = in.readInt();
75        mFromLayout = in.readInt() != 0;
76        mFragmentId = in.readInt();
77        mContainerId = in.readInt();
78        mTag = in.readString();
79        mRetainInstance = in.readInt() != 0;
80        mArguments = in.readBundle();
81        mSavedFragmentState = in.readBundle();
82    }
83
84    public Fragment instantiate(Activity activity) {
85        if (mInstance != null) {
86            return mInstance;
87        }
88
89        if (mArguments != null) {
90            mArguments.setClassLoader(activity.getClassLoader());
91        }
92
93        mInstance = Fragment.instantiate(activity, mClassName, mArguments);
94
95        if (mSavedFragmentState != null) {
96            mSavedFragmentState.setClassLoader(activity.getClassLoader());
97            mInstance.mSavedFragmentState = mSavedFragmentState;
98        }
99        mInstance.setIndex(mIndex);
100        mInstance.mFromLayout = mFromLayout;
101        mInstance.mRestored = true;
102        mInstance.mFragmentId = mFragmentId;
103        mInstance.mContainerId = mContainerId;
104        mInstance.mTag = mTag;
105        mInstance.mRetainInstance = mRetainInstance;
106        mInstance.mFragmentManager = activity.mFragments;
107
108        return mInstance;
109    }
110
111    public int describeContents() {
112        return 0;
113    }
114
115    public void writeToParcel(Parcel dest, int flags) {
116        dest.writeString(mClassName);
117        dest.writeInt(mIndex);
118        dest.writeInt(mFromLayout ? 1 : 0);
119        dest.writeInt(mFragmentId);
120        dest.writeInt(mContainerId);
121        dest.writeString(mTag);
122        dest.writeInt(mRetainInstance ? 1 : 0);
123        dest.writeBundle(mArguments);
124        dest.writeBundle(mSavedFragmentState);
125    }
126
127    public static final Parcelable.Creator<FragmentState> CREATOR
128            = new Parcelable.Creator<FragmentState>() {
129        public FragmentState createFromParcel(Parcel in) {
130            return new FragmentState(in);
131        }
132
133        public FragmentState[] newArray(int size) {
134            return new FragmentState[size];
135        }
136    };
137}
138
139/**
140 * A Fragment is a piece of an application's user interface or behavior
141 * that can be placed in an {@link Activity}.  Interaction with fragments
142 * is done through {@link FragmentManager}, which can be obtained via
143 * {@link Activity#getFragmentManager() Activity.getFragmentManager()} and
144 * {@link Fragment#getFragmentManager() Fragment.getFragmentManager()}.
145 *
146 * <p>The Fragment class can be used many ways to achieve a wide variety of
147 * results.  It is core, it represents a particular operation or interface
148 * that is running within a larger {@link Activity}.  A Fragment is closely
149 * tied to the Activity it is in, and can not be used apart from one.  Though
150 * Fragment defines its own lifecycle, that lifecycle is dependent on its
151 * activity: if the activity is stopped, no fragments inside of it can be
152 * started; when the activity is destroyed, all fragments will be destroyed.
153 *
154 * <p>All subclasses of Fragment must include a public empty constructor.
155 * The framework will often re-instantiate a fragment class when needed,
156 * in particular during state restore, and needs to be able to find this
157 * constructor to instantiate it.  If the empty constructor is not available,
158 * a runtime exception will occur in some cases during state restore.
159 *
160 * <p>Topics covered here:
161 * <ol>
162 * <li><a href="#Lifecycle">Lifecycle</a>
163 * <li><a href="#Layout">Layout</a>
164 * <li><a href="#BackStack">Back Stack</a>
165 * </ol>
166 *
167 * <a name="Lifecycle"></a>
168 * <h3>Lifecycle</h3>
169 *
170 * <p>Though a Fragment's lifecycle is tied to its owning activity, it has
171 * its own wrinkle on the standard activity lifecycle.  It includes basic
172 * activity lifecycle methods such as {@link #onResume}, but also important
173 * are methods related to interactions with the activity and UI generation.
174 *
175 * <p>The core series of lifecycle methods that are called to bring a fragment
176 * up to resumed state (interacting with the user) are:
177 *
178 * <ol>
179 * <li> {@link #onAttach} called once the fragment is associated with its activity.
180 * <li> {@link #onCreate} called to do initial creation of the fragment.
181 * <li> {@link #onCreateView} creates and returns the view hierarchy associated
182 * with the fragment.
183 * <li> {@link #onActivityCreated} tells the fragment that its activity has
184 * completed its own {@link Activity#onCreate Activity.onCreaate}.
185 * <li> {@link #onStart} makes the fragment visible to the user (based on its
186 * containing activity being started).
187 * <li> {@link #onResume} makes the fragment interacting with the user (based on its
188 * containing activity being resumed).
189 * </ol>
190 *
191 * <p>As a fragment is no longer being used, it goes through a reverse
192 * series of callbacks:
193 *
194 * <ol>
195 * <li> {@link #onPause} fragment is no longer interacting with the user either
196 * because its activity is being paused or a fragment operation is modifying it
197 * in the activity.
198 * <li> {@link #onStop} fragment is no longer visible to the user either
199 * because its activity is being stopped or a fragment operation is modifying it
200 * in the activity.
201 * <li> {@link #onDestroyView} allows the fragment to clean up resources
202 * associated with its View.
203 * <li> {@link #onDestroy} called to do final cleanup of the fragment's state.
204 * <li> {@link #onDetach} called immediately prior to the fragment no longer
205 * being associated with its activity.
206 * </ol>
207 *
208 * <a name="Layout"></a>
209 * <h3>Layout</h3>
210 *
211 * <p>Fragments can be used as part of your application's layout, allowing
212 * you to better modularize your code and more easily adjust your user
213 * interface to the screen it is running on.  As an example, we can look
214 * at a simple program consisting of a list of items, and display of the
215 * details of each item.</p>
216 *
217 * <p>An activity's layout XML can include <code>&lt;fragment&gt;</code> tags
218 * to embed fragment instances inside of the layout.  For example, here is
219 * a simple layout that embeds one fragment:</p>
220 *
221 * {@sample development/samples/ApiDemos/res/layout/fragment_layout.xml layout}
222 *
223 * <p>The layout is installed in the activity in the normal way:</p>
224 *
225 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java
226 *      main}
227 *
228 * <p>The titles fragment, showing a list of titles, is very simple, relying
229 * on {@link ListFragment} for most of its work.  Note the implementation of
230 * clicking an item, which can either update
231 * the content of the details fragment or start a new activity show the
232 * details depending on whether the current activity's layout can show the
233 * details.</p>
234 *
235 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java
236 *      titles}
237 *
238 * <p>The details fragment showing the contents of selected item here just
239 * displays a string of text based on an index of a string array built in to
240 * the app:</p>
241 *
242 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java
243 *      details}
244 *
245 * <p>In this case when the user clicks on a title, there is no details
246 * fragment in the current activity, so the title title fragment's click code will
247 * launch a new activity to display the details fragment:</p>
248 *
249 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java
250 *      details_activity}
251 *
252 * <p>However the screen may be large enough to show both the list of titles
253 * and details about the currently selected title.  To use such a layout on
254 * a landscape screen, this alternative layout can be placed under layout-land:</p>
255 *
256 * {@sample development/samples/ApiDemos/res/layout-land/fragment_layout.xml layout}
257 *
258 * <p>Note how the prior code will adjust to this alternative UI flow: the
259 * titles fragment will now show its text inside of its activity, and the
260 * details activity will finish of it finds itself running in a configuration
261 * where the details can be shown inline.
262 *
263 * <p>When a configuration change causes the activity hosting these fragments
264 * to restart, its new instance may use a different layout that doesn't
265 * include the same fragments as the previous layout.  In this case all of
266 * the previous fragments will still be instantiated and running in the new
267 * instance; however, any that are no longer associated with a &lt;fragment&gt;
268 * tag in the view hierarchy will not have their content view created and will
269 * return false from {@link #isInLayout}.
270 *
271 * <p>The attributes of the &lt;fragment&gt; tag are used to control the
272 * LayoutParams provider when attaching the fragment's view to the parent
273 * container.  They can alse be parsed by the fragment in {@link #onInflate}
274 * as parameters.
275 *
276 * <p>The fragment being instantiated must have some kind of unique identifier
277 * so that it can be re-associated with a previous instance if the parent
278 * activity needs to be destroyed and recreated.  This can be provided these
279 * ways:
280 *
281 * <ul>
282 * <li>If nothing is explicitly supplied, the view ID of the container will
283 * be used.
284 * <li><code>android:tag</code> can be used in &lt;fragment&gt; to provide
285 * a specific tag name for the fragment.
286 * <li><code>android:id</code> can be used in &lt;fragment&gt; to provide
287 * a specific identifier for the fragment.
288 * </ul>
289 *
290 * <a name="BackStack"></a>
291 * <h3>Back Stack</h3>
292 *
293 * <p>The transaction in which fragments are modified can be placed on an
294 * internal back-stack of the owning activity.  When the user presses back
295 * in the activity, any transactions on the back stack are popped off before
296 * the activity itself is finished.
297 *
298 * <p>For example, consider this simple fragment that is instantiated with
299 * an integer argument and displays that in a TextView in its UI:</p>
300 *
301 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentStack.java
302 *      fragment}
303 *
304 * <p>A function that creates a new instance of the fragment, replacing
305 * whatever current fragment instance is being shown and pushing that change
306 * on to the back stack could be written as:
307 *
308 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentStack.java
309 *      add_stack}
310 *
311 * <p>After each call to this function, a new entry is on the stack, and
312 * pressing back will pop it to return the user to whatever previous state
313 * the activity UI was in.
314 */
315public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener {
316    private static final HashMap<String, Class<?>> sClassMap =
317            new HashMap<String, Class<?>>();
318
319    static final int INITIALIZING = 0;     // Not yet created.
320    static final int CREATED = 1;          // Created.
321    static final int ACTIVITY_CREATED = 2; // The activity has finished its creation.
322    static final int STARTED = 3;          // Created and started, not resumed.
323    static final int RESUMED = 4;          // Created started and resumed.
324
325    int mState = INITIALIZING;
326
327    // Non-null if the fragment's view hierarchy is currently animating away,
328    // meaning we need to wait a bit on completely destroying it.  This is the
329    // animation that is running.
330    Animator mAnimatingAway;
331
332    // If mAnimatingAway != null, this is the state we should move to once the
333    // animation is done.
334    int mStateAfterAnimating;
335
336    // When instantiated from saved state, this is the saved state.
337    Bundle mSavedFragmentState;
338    SparseArray<Parcelable> mSavedViewState;
339
340    // Index into active fragment array.
341    int mIndex = -1;
342
343    // Internal unique name for this fragment;
344    String mWho;
345
346    // Construction arguments;
347    Bundle mArguments;
348
349    // Target fragment.
350    Fragment mTarget;
351
352    // Target request code.
353    int mTargetRequestCode;
354
355    // True if the fragment is in the list of added fragments.
356    boolean mAdded;
357
358    // True if the fragment is in the resumed state.
359    boolean mResumed;
360
361    // Set to true if this fragment was instantiated from a layout file.
362    boolean mFromLayout;
363
364    // Set to true when the view has actually been inflated in its layout.
365    boolean mInLayout;
366
367    // True if this fragment has been restored from previously saved state.
368    boolean mRestored;
369
370    // Number of active back stack entries this fragment is in.
371    int mBackStackNesting;
372
373    // The fragment manager we are associated with.  Set as soon as the
374    // fragment is used in a transaction; cleared after it has been removed
375    // from all transactions.
376    FragmentManager mFragmentManager;
377
378    // Set as soon as a fragment is added to a transaction (or removed),
379    // to be able to do validation.
380    Activity mImmediateActivity;
381
382    // Activity this fragment is attached to.
383    Activity mActivity;
384
385    // The optional identifier for this fragment -- either the container ID if it
386    // was dynamically added to the view hierarchy, or the ID supplied in
387    // layout.
388    int mFragmentId;
389
390    // When a fragment is being dynamically added to the view hierarchy, this
391    // is the identifier of the parent container it is being added to.
392    int mContainerId;
393
394    // The optional named tag for this fragment -- usually used to find
395    // fragments that are not part of the layout.
396    String mTag;
397
398    // Set to true when the app has requested that this fragment be hidden
399    // from the user.
400    boolean mHidden;
401
402    // If set this fragment would like its instance retained across
403    // configuration changes.
404    boolean mRetainInstance;
405
406    // If set this fragment is being retained across the current config change.
407    boolean mRetaining;
408
409    // If set this fragment has menu items to contribute.
410    boolean mHasMenu;
411
412    // Used to verify that subclasses call through to super class.
413    boolean mCalled;
414
415    // If app has requested a specific animation, this is the one to use.
416    int mNextAnim;
417
418    // The parent container of the fragment after dynamically added to UI.
419    ViewGroup mContainer;
420
421    // The View generated for this fragment.
422    View mView;
423
424    LoaderManagerImpl mLoaderManager;
425    boolean mLoadersStarted;
426    boolean mCheckedForLoaderManager;
427
428    /**
429     * Thrown by {@link Fragment#instantiate(Context, String, Bundle)} when
430     * there is an instantiation failure.
431     */
432    static public class InstantiationException extends AndroidRuntimeException {
433        public InstantiationException(String msg, Exception cause) {
434            super(msg, cause);
435        }
436    }
437
438    /**
439     * Default constructor.  <strong>Every</strong> fragment must have an
440     * empty constructor, so it can be instantiated when restoring its
441     * activity's state.  It is strongly recommended that subclasses do not
442     * have other constructors with parameters, since these constructors
443     * will not be called when the fragment is re-instantiated; instead,
444     * arguments can be supplied by the caller with {@link #setArguments}
445     * and later retrieved by the Fragment with {@link #getArguments}.
446     *
447     * <p>Applications should generally not implement a constructor.  The
448     * first place application code an run where the fragment is ready to
449     * be used is in {@link #onAttach(Activity)}, the point where the fragment
450     * is actually associated with its activity.  Some applications may also
451     * want to implement {@link #onInflate} to retrieve attributes from a
452     * layout resource, though should take care here because this happens for
453     * the fragment is attached to its activity.
454     */
455    public Fragment() {
456    }
457
458    /**
459     * Like {@link #instantiate(Context, String, Bundle)} but with a null
460     * argument Bundle.
461     */
462    public static Fragment instantiate(Context context, String fname) {
463        return instantiate(context, fname, null);
464    }
465
466    /**
467     * Create a new instance of a Fragment with the given class name.  This is
468     * the same as calling its empty constructor.
469     *
470     * @param context The calling context being used to instantiate the fragment.
471     * This is currently just used to get its ClassLoader.
472     * @param fname The class name of the fragment to instantiate.
473     * @param args Bundle of arguments to supply to the fragment, which it
474     * can retrieve with {@link #getArguments()}.  May be null.
475     * @return Returns a new fragment instance.
476     * @throws InstantiationException If there is a failure in instantiating
477     * the given fragment class.  This is a runtime exception; it is not
478     * normally expected to happen.
479     */
480    public static Fragment instantiate(Context context, String fname, Bundle args) {
481        try {
482            Class<?> clazz = sClassMap.get(fname);
483            if (clazz == null) {
484                // Class not found in the cache, see if it's real, and try to add it
485                clazz = context.getClassLoader().loadClass(fname);
486                sClassMap.put(fname, clazz);
487            }
488            Fragment f = (Fragment)clazz.newInstance();
489            if (args != null) {
490                args.setClassLoader(f.getClass().getClassLoader());
491                f.mArguments = args;
492            }
493            return f;
494        } catch (ClassNotFoundException e) {
495            throw new InstantiationException("Unable to instantiate fragment " + fname
496                    + ": make sure class name exists, is public, and has an"
497                    + " empty constructor that is public", e);
498        } catch (java.lang.InstantiationException e) {
499            throw new InstantiationException("Unable to instantiate fragment " + fname
500                    + ": make sure class name exists, is public, and has an"
501                    + " empty constructor that is public", e);
502        } catch (IllegalAccessException e) {
503            throw new InstantiationException("Unable to instantiate fragment " + fname
504                    + ": make sure class name exists, is public, and has an"
505                    + " empty constructor that is public", e);
506        }
507    }
508
509    void restoreViewState() {
510        if (mSavedViewState != null) {
511            mView.restoreHierarchyState(mSavedViewState);
512            mSavedViewState = null;
513        }
514    }
515
516    void setIndex(int index) {
517        mIndex = index;
518        mWho = "android:fragment:" + mIndex;
519   }
520
521    void clearIndex() {
522        mIndex = -1;
523        mWho = null;
524    }
525
526    /**
527     * Subclasses can not override equals().
528     */
529    @Override final public boolean equals(Object o) {
530        return super.equals(o);
531    }
532
533    /**
534     * Subclasses can not override hashCode().
535     */
536    @Override final public int hashCode() {
537        return super.hashCode();
538    }
539
540    @Override
541    public String toString() {
542        StringBuilder sb = new StringBuilder(128);
543        DebugUtils.buildShortClassTag(this, sb);
544        if (mIndex >= 0) {
545            sb.append(" #");
546            sb.append(mIndex);
547        }
548        if (mFragmentId != 0) {
549            sb.append(" id=0x");
550            sb.append(Integer.toHexString(mFragmentId));
551        }
552        if (mTag != null) {
553            sb.append(" ");
554            sb.append(mTag);
555        }
556        sb.append('}');
557        return sb.toString();
558    }
559
560    /**
561     * Return the identifier this fragment is known by.  This is either
562     * the android:id value supplied in a layout or the container view ID
563     * supplied when adding the fragment.
564     */
565    final public int getId() {
566        return mFragmentId;
567    }
568
569    /**
570     * Get the tag name of the fragment, if specified.
571     */
572    final public String getTag() {
573        return mTag;
574    }
575
576    /**
577     * Supply the construction arguments for this fragment.  This can only
578     * be called before the fragment has been attached to its activity; that
579     * is, you should call it immediately after constructing the fragment.  The
580     * arguments supplied here will be retained across fragment destroy and
581     * creation.
582     */
583    public void setArguments(Bundle args) {
584        if (mIndex >= 0) {
585            throw new IllegalStateException("Fragment already active");
586        }
587        mArguments = args;
588    }
589
590    /**
591     * Return the arguments supplied when the fragment was instantiated,
592     * if any.
593     */
594    final public Bundle getArguments() {
595        return mArguments;
596    }
597
598    /**
599     * Optional target for this fragment.  This may be used, for example,
600     * if this fragment is being started by another, and when done wants to
601     * give a result back to the first.  The target set here is retained
602     * across instances via {@link FragmentManager#putFragment
603     * FragmentManager.putFragment()}.
604     *
605     * @param fragment The fragment that is the target of this one.
606     * @param requestCode Optional request code, for convenience if you
607     * are going to call back with {@link #onActivityResult(int, int, Intent)}.
608     */
609    public void setTargetFragment(Fragment fragment, int requestCode) {
610        mTarget = fragment;
611        mTargetRequestCode = requestCode;
612    }
613
614    /**
615     * Return the target fragment set by {@link #setTargetFragment}.
616     */
617    final public Fragment getTargetFragment() {
618        return mTarget;
619    }
620
621    /**
622     * Return the target request code set by {@link #setTargetFragment}.
623     */
624    final public int getTargetRequestCode() {
625        return mTargetRequestCode;
626    }
627
628    /**
629     * Return the Activity this fragment is currently associated with.
630     */
631    final public Activity getActivity() {
632        return mActivity;
633    }
634
635    /**
636     * Return <code>getActivity().getResources()</code>.
637     */
638    final public Resources getResources() {
639        return mActivity.getResources();
640    }
641
642    /**
643     * Return a localized, styled CharSequence from the application's package's
644     * default string table.
645     *
646     * @param resId Resource id for the CharSequence text
647     */
648    public final CharSequence getText(int resId) {
649        return getResources().getText(resId);
650    }
651
652    /**
653     * Return a localized string from the application's package's
654     * default string table.
655     *
656     * @param resId Resource id for the string
657     */
658    public final String getString(int resId) {
659        return getResources().getString(resId);
660    }
661
662    /**
663     * Return a localized formatted string from the application's package's
664     * default string table, substituting the format arguments as defined in
665     * {@link java.util.Formatter} and {@link java.lang.String#format}.
666     *
667     * @param resId Resource id for the format string
668     * @param formatArgs The format arguments that will be used for substitution.
669     */
670
671    public final String getString(int resId, Object... formatArgs) {
672        return getResources().getString(resId, formatArgs);
673    }
674
675    /**
676     * Return the FragmentManager for interacting with fragments associated
677     * with this fragment's activity.  Note that this will be non-null slightly
678     * before {@link #getActivity()}, during the time from when the fragment is
679     * placed in a {@link FragmentTransaction} until it is committed and
680     * attached to its activity.
681     */
682    final public FragmentManager getFragmentManager() {
683        return mFragmentManager;
684    }
685
686    /**
687     * Return true if the fragment is currently added to its activity.
688     */
689    final public boolean isAdded() {
690        return mActivity != null && mActivity.mFragments.mAdded.contains(this);
691    }
692
693    /**
694     * Return true if the layout is included as part of an activity view
695     * hierarchy via the &lt;fragment&gt; tag.  This will always be true when
696     * fragments are created through the &lt;fragment&gt; tag, <em>except</em>
697     * in the case where an old fragment is restored from a previous state and
698     * it does not appear in the layout of the current state.
699     */
700    final public boolean isInLayout() {
701        return mInLayout;
702    }
703
704    /**
705     * Return true if the fragment is in the resumed state.  This is true
706     * for the duration of {@link #onResume()} and {@link #onPause()} as well.
707     */
708    final public boolean isResumed() {
709        return mResumed;
710    }
711
712    /**
713     * Return true if the fragment is currently visible to the user.  This means
714     * it: (1) has been added, (2) has its view attached to the window, and
715     * (3) is not hidden.
716     */
717    final public boolean isVisible() {
718        return isAdded() && !isHidden() && mView != null
719                && mView.getWindowToken() != null && mView.getVisibility() == View.VISIBLE;
720    }
721
722    /**
723     * Return true if the fragment has been hidden.  By default fragments
724     * are shown.  You can find out about changes to this state with
725     * {@link #onHiddenChanged}.  Note that the hidden state is orthogonal
726     * to other states -- that is, to be visible to the user, a fragment
727     * must be both started and not hidden.
728     */
729    final public boolean isHidden() {
730        return mHidden;
731    }
732
733    /**
734     * Called when the hidden state (as returned by {@link #isHidden()} of
735     * the fragment has changed.  Fragments start out not hidden; this will
736     * be called whenever the fragment changes state from that.
737     * @param hidden True if the fragment is now hidden, false if it is not
738     * visible.
739     */
740    public void onHiddenChanged(boolean hidden) {
741    }
742
743    /**
744     * Control whether a fragment instance is retained across Activity
745     * re-creation (such as from a configuration change).  This can only
746     * be used with fragments not in the back stack.  If set, the fragment
747     * lifecycle will be slightly different when an activity is recreated:
748     * <ul>
749     * <li> {@link #onDestroy()} will not be called (but {@link #onDetach()} still
750     * will be, because the fragment is being detached from its current activity).
751     * <li> {@link #onCreate(Bundle)} will not be called since the fragment
752     * is not being re-created.
753     * <li> {@link #onAttach(Activity)} and {@link #onActivityCreated(Bundle)} <b>will</b>
754     * still be called.
755     * </ul>
756     */
757    public void setRetainInstance(boolean retain) {
758        mRetainInstance = retain;
759    }
760
761    final public boolean getRetainInstance() {
762        return mRetainInstance;
763    }
764
765    /**
766     * Report that this fragment would like to participate in populating
767     * the options menu by receiving a call to {@link #onCreateOptionsMenu}
768     * and related methods.
769     *
770     * @param hasMenu If true, the fragment has menu items to contribute.
771     */
772    public void setHasOptionsMenu(boolean hasMenu) {
773        if (mHasMenu != hasMenu) {
774            mHasMenu = hasMenu;
775            if (isAdded() && !isHidden()) {
776                mActivity.invalidateOptionsMenu();
777            }
778        }
779    }
780
781    /**
782     * Return the LoaderManager for this fragment, creating it if needed.
783     */
784    public LoaderManager getLoaderManager() {
785        if (mLoaderManager != null) {
786            return mLoaderManager;
787        }
788        mCheckedForLoaderManager = true;
789        mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, true);
790        return mLoaderManager;
791    }
792
793    /**
794     * Call {@link Activity#startActivity(Intent)} on the fragment's
795     * containing Activity.
796     */
797    public void startActivity(Intent intent) {
798        mActivity.startActivityFromFragment(this, intent, -1);
799    }
800
801    /**
802     * Call {@link Activity#startActivityForResult(Intent, int)} on the fragment's
803     * containing Activity.
804     */
805    public void startActivityForResult(Intent intent, int requestCode) {
806        mActivity.startActivityFromFragment(this, intent, requestCode);
807    }
808
809    /**
810     * Receive the result from a previous call to
811     * {@link #startActivityForResult(Intent, int)}.  This follows the
812     * related Activity API as described there in
813     * {@link Activity#onActivityResult(int, int, Intent)}.
814     *
815     * @param requestCode The integer request code originally supplied to
816     *                    startActivityForResult(), allowing you to identify who this
817     *                    result came from.
818     * @param resultCode The integer result code returned by the child activity
819     *                   through its setResult().
820     * @param data An Intent, which can return result data to the caller
821     *               (various data can be attached to Intent "extras").
822     */
823    public void onActivityResult(int requestCode, int resultCode, Intent data) {
824    }
825
826    /**
827     * Called when a fragment is being created as part of a view layout
828     * inflation, typically from setting the content view of an activity.  This
829     * will be called immediately after the fragment is created from a <fragment>
830     * tag in a layout file.  Note this is <em>before</em> the fragment's
831     * {@link #onAttach(Activity)} has been called; all you should do here is
832     * parse the attributes and save them away.  A convenient thing to do is
833     * simply copy them into a Bundle that is given to {@link #setArguments(Bundle)}.
834     *
835     * <p>This is called every time the fragment is inflated, even if it is
836     * being inflated into a new instance with saved state.  Because a fragment's
837     * arguments are retained across instances, it may make no sense to re-parse
838     * the attributes into new arguments.  You may want to first check
839     * {@link #getArguments()} and only parse the attributes if it returns null,
840     * the assumption being that if it is non-null those are the same arguments
841     * from the first time the fragment was inflated.  (That said, you may want
842     * to have layouts change for different configurations such as landscape
843     * and portrait, which can have different attributes.  If so, you will need
844     * to re-parse the attributes each time this is called to generate new
845     * arguments.)</p>
846     *
847     * @param attrs The attributes at the tag where the fragment is
848     * being created.
849     * @param savedInstanceState If the fragment is being re-created from
850     * a previous saved state, this is the state.
851     */
852    public void onInflate(AttributeSet attrs, Bundle savedInstanceState) {
853        mCalled = true;
854    }
855
856    /**
857     * Called when a fragment is first attached to its activity.
858     * {@link #onCreate(Bundle)} will be called after this.
859     */
860    public void onAttach(Activity activity) {
861        mCalled = true;
862    }
863
864    /**
865     * Called when a fragment loads an animation.
866     */
867    public Animator onCreateAnimator(int transit, boolean enter, int nextAnim) {
868        return null;
869    }
870
871    /**
872     * Called to do initial creation of a fragment.  This is called after
873     * {@link #onAttach(Activity)} and before
874     * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}.
875     *
876     * <p>Note that this can be called while the fragment's activity is
877     * still in the process of being created.  As such, you can not rely
878     * on things like the activity's content view hierarchy being initialized
879     * at this point.  If you want to do work once the activity itself is
880     * created, see {@link #onActivityCreated(Bundle)}.
881     *
882     * @param savedInstanceState If the fragment is being re-created from
883     * a previous saved state, this is the state.
884     */
885    public void onCreate(Bundle savedInstanceState) {
886        mCalled = true;
887    }
888
889    /**
890     * Called to have the fragment instantiate its user interface view.
891     * This is optional, and non-graphical fragments can return null (which
892     * is the default implementation).  This will be called between
893     * {@link #onCreate(Bundle)} and {@link #onActivityCreated(Bundle)}.
894     *
895     * <p>If you return a View from here, you will later be called in
896     * {@link #onDestroyView} when the view is being released.
897     *
898     * @param inflater The LayoutInflater object that can be used to inflate
899     * any views in the fragment,
900     * @param container If non-null, this is the parent view that the fragment's
901     * UI should be attached to.  The fragment should not add the view itself,
902     * but this can be used to generate the LayoutParams of the view.
903     * @param savedInstanceState If non-null, this fragment is being re-constructed
904     * from a previous saved state as given here.
905     *
906     * @return Return the View for the fragment's UI, or null.
907     */
908    public View onCreateView(LayoutInflater inflater, ViewGroup container,
909            Bundle savedInstanceState) {
910        return null;
911    }
912
913    public View getView() {
914        return mView;
915    }
916
917    /**
918     * Called when the fragment's activity has been created and this
919     * fragment's view hierarchy instantiated.  It can be used to do final
920     * initialization once these pieces are in place, such as retrieving
921     * views or restoring state.  It is also useful for fragments that use
922     * {@link #setRetainInstance(boolean)} to retain their instance,
923     * as this callback tells the fragment when it is fully associated with
924     * the new activity instance.  This is called after {@link #onCreateView}
925     * and before {@link #onStart()}.
926     *
927     * @param savedInstanceState If the fragment is being re-created from
928     * a previous saved state, this is the state.
929     */
930    public void onActivityCreated(Bundle savedInstanceState) {
931        mCalled = true;
932    }
933
934    /**
935     * Called when the Fragment is visible to the user.  This is generally
936     * tied to {@link Activity#onStart() Activity.onStart} of the containing
937     * Activity's lifecycle.
938     */
939    public void onStart() {
940        mCalled = true;
941
942        if (!mLoadersStarted) {
943            mLoadersStarted = true;
944            if (!mCheckedForLoaderManager) {
945                mCheckedForLoaderManager = true;
946                mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false);
947            }
948            if (mLoaderManager != null) {
949                mLoaderManager.doStart();
950            }
951        }
952    }
953
954    /**
955     * Called when the fragment is visible to the user and actively running.
956     * This is generally
957     * tied to {@link Activity#onResume() Activity.onResume} of the containing
958     * Activity's lifecycle.
959     */
960    public void onResume() {
961        mCalled = true;
962    }
963
964    /**
965     * Called to ask the fragment to save its current dynamic state, so it
966     * can later be reconstructed in a new instance of its process is
967     * restarted.  If a new instance of the fragment later needs to be
968     * created, the data you place in the Bundle here will be available
969     * in the Bundle given to {@link #onCreate(Bundle)},
970     * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}, and
971     * {@link #onActivityCreated(Bundle)}.
972     *
973     * <p>This corresponds to {@link Activity#onSaveInstanceState(Bundle)
974     * Activity.onSaveInstanceState(Bundle)} and most of the discussion there
975     * applies here as well.  Note however: <em>this method may be called
976     * at any time before {@link #onDestroy()}</em>.  There are many situations
977     * where a fragment may be mostly torn down (such as when placed on the
978     * back stack with no UI showing), but its state will not be saved until
979     * its owning activity actually needs to save its state.
980     *
981     * @param outState Bundle in which to place your saved state.
982     */
983    public void onSaveInstanceState(Bundle outState) {
984    }
985
986    public void onConfigurationChanged(Configuration newConfig) {
987        mCalled = true;
988    }
989
990    /**
991     * Called when the Fragment is no longer resumed.  This is generally
992     * tied to {@link Activity#onPause() Activity.onPause} of the containing
993     * Activity's lifecycle.
994     */
995    public void onPause() {
996        mCalled = true;
997    }
998
999    /**
1000     * Called when the Fragment is no longer started.  This is generally
1001     * tied to {@link Activity#onStop() Activity.onStop} of the containing
1002     * Activity's lifecycle.
1003     */
1004    public void onStop() {
1005        mCalled = true;
1006    }
1007
1008    public void onLowMemory() {
1009        mCalled = true;
1010    }
1011
1012    /**
1013     * Called when the view previously created by {@link #onCreateView} has
1014     * been detached from the fragment.  The next time the fragment needs
1015     * to be displayed, a new view will be created.  This is called
1016     * after {@link #onStop()} and before {@link #onDestroy()}.  It is called
1017     * <em>regardless</em> of whether {@link #onCreateView} returned a
1018     * non-null view.  Internally it is called after the view's state has
1019     * been saved but before it has been removed from its parent.
1020     */
1021    public void onDestroyView() {
1022        mCalled = true;
1023    }
1024
1025    /**
1026     * Called when the fragment is no longer in use.  This is called
1027     * after {@link #onStop()} and before {@link #onDetach()}.
1028     */
1029    public void onDestroy() {
1030        mCalled = true;
1031        //Log.v("foo", "onDestroy: mCheckedForLoaderManager=" + mCheckedForLoaderManager
1032        //        + " mLoaderManager=" + mLoaderManager);
1033        if (!mCheckedForLoaderManager) {
1034            mCheckedForLoaderManager = true;
1035            mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false);
1036        }
1037        if (mLoaderManager != null) {
1038            mLoaderManager.doDestroy();
1039        }
1040    }
1041
1042    /**
1043     * Called when the fragment is no longer attached to its activity.  This
1044     * is called after {@link #onDestroy()}.
1045     */
1046    public void onDetach() {
1047        mCalled = true;
1048    }
1049
1050    /**
1051     * Initialize the contents of the Activity's standard options menu.  You
1052     * should place your menu items in to <var>menu</var>.  For this method
1053     * to be called, you must have first called {@link #setHasOptionsMenu}.  See
1054     * {@link Activity#onCreateOptionsMenu(Menu) Activity.onCreateOptionsMenu}
1055     * for more information.
1056     *
1057     * @param menu The options menu in which you place your items.
1058     *
1059     * @see #setHasOptionsMenu
1060     * @see #onPrepareOptionsMenu
1061     * @see #onOptionsItemSelected
1062     */
1063    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
1064    }
1065
1066    /**
1067     * Prepare the Screen's standard options menu to be displayed.  This is
1068     * called right before the menu is shown, every time it is shown.  You can
1069     * use this method to efficiently enable/disable items or otherwise
1070     * dynamically modify the contents.  See
1071     * {@link Activity#onPrepareOptionsMenu(Menu) Activity.onPrepareOptionsMenu}
1072     * for more information.
1073     *
1074     * @param menu The options menu as last shown or first initialized by
1075     *             onCreateOptionsMenu().
1076     *
1077     * @see #setHasOptionsMenu
1078     * @see #onCreateOptionsMenu
1079     */
1080    public void onPrepareOptionsMenu(Menu menu) {
1081    }
1082
1083    /**
1084     * Called when this fragment's option menu items are no longer being
1085     * included in the overall options menu.  Receiving this call means that
1086     * the menu needed to be rebuilt, but this fragment's items were not
1087     * included in the newly built menu (its {@link #onCreateOptionsMenu(Menu, MenuInflater)}
1088     * was not called).
1089     */
1090    public void onDestroyOptionsMenu() {
1091    }
1092
1093    /**
1094     * This hook is called whenever an item in your options menu is selected.
1095     * The default implementation simply returns false to have the normal
1096     * processing happen (calling the item's Runnable or sending a message to
1097     * its Handler as appropriate).  You can use this method for any items
1098     * for which you would like to do processing without those other
1099     * facilities.
1100     *
1101     * <p>Derived classes should call through to the base class for it to
1102     * perform the default menu handling.
1103     *
1104     * @param item The menu item that was selected.
1105     *
1106     * @return boolean Return false to allow normal menu processing to
1107     *         proceed, true to consume it here.
1108     *
1109     * @see #onCreateOptionsMenu
1110     */
1111    public boolean onOptionsItemSelected(MenuItem item) {
1112        return false;
1113    }
1114
1115    /**
1116     * This hook is called whenever the options menu is being closed (either by the user canceling
1117     * the menu with the back/menu button, or when an item is selected).
1118     *
1119     * @param menu The options menu as last shown or first initialized by
1120     *             onCreateOptionsMenu().
1121     */
1122    public void onOptionsMenuClosed(Menu menu) {
1123    }
1124
1125    /**
1126     * Called when a context menu for the {@code view} is about to be shown.
1127     * Unlike {@link #onCreateOptionsMenu}, this will be called every
1128     * time the context menu is about to be shown and should be populated for
1129     * the view (or item inside the view for {@link AdapterView} subclasses,
1130     * this can be found in the {@code menuInfo})).
1131     * <p>
1132     * Use {@link #onContextItemSelected(android.view.MenuItem)} to know when an
1133     * item has been selected.
1134     * <p>
1135     * The default implementation calls up to
1136     * {@link Activity#onCreateContextMenu Activity.onCreateContextMenu}, though
1137     * you can not call this implementation if you don't want that behavior.
1138     * <p>
1139     * It is not safe to hold onto the context menu after this method returns.
1140     * {@inheritDoc}
1141     */
1142    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
1143        getActivity().onCreateContextMenu(menu, v, menuInfo);
1144    }
1145
1146    /**
1147     * Registers a context menu to be shown for the given view (multiple views
1148     * can show the context menu). This method will set the
1149     * {@link OnCreateContextMenuListener} on the view to this fragment, so
1150     * {@link #onCreateContextMenu(ContextMenu, View, ContextMenuInfo)} will be
1151     * called when it is time to show the context menu.
1152     *
1153     * @see #unregisterForContextMenu(View)
1154     * @param view The view that should show a context menu.
1155     */
1156    public void registerForContextMenu(View view) {
1157        view.setOnCreateContextMenuListener(this);
1158    }
1159
1160    /**
1161     * Prevents a context menu to be shown for the given view. This method will
1162     * remove the {@link OnCreateContextMenuListener} on the view.
1163     *
1164     * @see #registerForContextMenu(View)
1165     * @param view The view that should stop showing a context menu.
1166     */
1167    public void unregisterForContextMenu(View view) {
1168        view.setOnCreateContextMenuListener(null);
1169    }
1170
1171    /**
1172     * This hook is called whenever an item in a context menu is selected. The
1173     * default implementation simply returns false to have the normal processing
1174     * happen (calling the item's Runnable or sending a message to its Handler
1175     * as appropriate). You can use this method for any items for which you
1176     * would like to do processing without those other facilities.
1177     * <p>
1178     * Use {@link MenuItem#getMenuInfo()} to get extra information set by the
1179     * View that added this menu item.
1180     * <p>
1181     * Derived classes should call through to the base class for it to perform
1182     * the default menu handling.
1183     *
1184     * @param item The context menu item that was selected.
1185     * @return boolean Return false to allow normal context menu processing to
1186     *         proceed, true to consume it here.
1187     */
1188    public boolean onContextItemSelected(MenuItem item) {
1189        return false;
1190    }
1191
1192    /**
1193     * Print the Fragments's state into the given stream.
1194     *
1195     * @param prefix Text to print at the front of each line.
1196     * @param fd The raw file descriptor that the dump is being sent to.
1197     * @param writer The PrintWriter to which you should dump your state.  This will be
1198     * closed for you after you return.
1199     * @param args additional arguments to the dump request.
1200     */
1201    public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) {
1202        writer.print(prefix); writer.print("mFragmentId=#");
1203                writer.print(Integer.toHexString(mFragmentId));
1204                writer.print(" mContainerId#=");
1205                writer.print(Integer.toHexString(mContainerId));
1206                writer.print(" mTag="); writer.println(mTag);
1207        writer.print(prefix); writer.print("mState="); writer.print(mState);
1208                writer.print(" mIndex="); writer.print(mIndex);
1209                writer.print(" mWho="); writer.print(mWho);
1210                writer.print(" mBackStackNesting="); writer.println(mBackStackNesting);
1211        writer.print(prefix); writer.print("mAdded="); writer.print(mAdded);
1212                writer.print(" mResumed="); writer.print(mResumed);
1213                writer.print(" mFromLayout="); writer.print(mFromLayout);
1214                writer.print(" mInLayout="); writer.println(mInLayout);
1215        writer.print(prefix); writer.print("mHidden="); writer.print(mHidden);
1216                writer.print(" mRetainInstance="); writer.print(mRetainInstance);
1217                writer.print(" mRetaining="); writer.print(mRetaining);
1218                writer.print(" mHasMenu="); writer.println(mHasMenu);
1219        if (mFragmentManager != null) {
1220            writer.print(prefix); writer.print("mFragmentManager=");
1221                    writer.println(mFragmentManager);
1222        }
1223        if (mImmediateActivity != null) {
1224            writer.print(prefix); writer.print("mImmediateActivity=");
1225                    writer.println(mImmediateActivity);
1226        }
1227        if (mActivity != null) {
1228            writer.print(prefix); writer.print("mActivity=");
1229                    writer.println(mActivity);
1230        }
1231        if (mArguments != null) {
1232            writer.print(prefix); writer.print("mArguments="); writer.println(mArguments);
1233        }
1234        if (mSavedFragmentState != null) {
1235            writer.print(prefix); writer.print("mSavedFragmentState=");
1236                    writer.println(mSavedFragmentState);
1237        }
1238        if (mSavedViewState != null) {
1239            writer.print(prefix); writer.print("mSavedViewState=");
1240                    writer.println(mSavedViewState);
1241        }
1242        if (mTarget != null) {
1243            writer.print(prefix); writer.print("mTarget="); writer.print(mTarget);
1244                    writer.print(" mTargetRequestCode=");
1245                    writer.println(mTargetRequestCode);
1246        }
1247        if (mNextAnim != 0) {
1248            writer.print(prefix); writer.print("mNextAnim="); writer.println(mNextAnim);
1249        }
1250        if (mContainer != null) {
1251            writer.print(prefix); writer.print("mContainer="); writer.println(mContainer);
1252        }
1253        if (mView != null) {
1254            writer.print(prefix); writer.print("mView="); writer.println(mView);
1255        }
1256        if (mAnimatingAway != null) {
1257            writer.print(prefix); writer.print("mAnimatingAway="); writer.println(mAnimatingAway);
1258            writer.print(prefix); writer.print("mStateAfterAnimating=");
1259                    writer.println(mStateAfterAnimating);
1260        }
1261        if (mLoaderManager != null) {
1262            writer.print(prefix); writer.println("Loader Manager:");
1263            mLoaderManager.dump(prefix + "  ", fd, writer, args);
1264        }
1265    }
1266
1267    void performStop() {
1268        onStop();
1269
1270        if (mLoadersStarted) {
1271            mLoadersStarted = false;
1272            if (!mCheckedForLoaderManager) {
1273                mCheckedForLoaderManager = true;
1274                mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false);
1275            }
1276            if (mLoaderManager != null) {
1277                if (mActivity == null || !mActivity.mChangingConfigurations) {
1278                    mLoaderManager.doStop();
1279                } else {
1280                    mLoaderManager.doRetain();
1281                }
1282            }
1283        }
1284    }
1285}
1286