1/*
2 * Copyright (C) 2006 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.widget;
18
19import android.content.BroadcastReceiver;
20import android.content.Context;
21import android.content.Intent;
22import android.content.IntentFilter;
23import android.content.res.TypedArray;
24import android.os.*;
25import android.util.AttributeSet;
26import android.util.Log;
27import android.view.accessibility.AccessibilityEvent;
28import android.view.accessibility.AccessibilityNodeInfo;
29import android.widget.RemoteViews.RemoteView;
30
31/**
32 * Simple {@link ViewAnimator} that will animate between two or more views
33 * that have been added to it.  Only one child is shown at a time.  If
34 * requested, can automatically flip between each child at a regular interval.
35 *
36 * @attr ref android.R.styleable#ViewFlipper_flipInterval
37 * @attr ref android.R.styleable#ViewFlipper_autoStart
38 */
39@RemoteView
40public class ViewFlipper extends ViewAnimator {
41    private static final String TAG = "ViewFlipper";
42    private static final boolean LOGD = false;
43
44    private static final int DEFAULT_INTERVAL = 3000;
45
46    private int mFlipInterval = DEFAULT_INTERVAL;
47    private boolean mAutoStart = false;
48
49    private boolean mRunning = false;
50    private boolean mStarted = false;
51    private boolean mVisible = false;
52    private boolean mUserPresent = true;
53
54    public ViewFlipper(Context context) {
55        super(context);
56    }
57
58    public ViewFlipper(Context context, AttributeSet attrs) {
59        super(context, attrs);
60
61        TypedArray a = context.obtainStyledAttributes(attrs,
62                com.android.internal.R.styleable.ViewFlipper);
63        mFlipInterval = a.getInt(
64                com.android.internal.R.styleable.ViewFlipper_flipInterval, DEFAULT_INTERVAL);
65        mAutoStart = a.getBoolean(
66                com.android.internal.R.styleable.ViewFlipper_autoStart, false);
67        a.recycle();
68    }
69
70    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
71        @Override
72        public void onReceive(Context context, Intent intent) {
73            final String action = intent.getAction();
74            if (Intent.ACTION_SCREEN_OFF.equals(action)) {
75                mUserPresent = false;
76                updateRunning();
77            } else if (Intent.ACTION_USER_PRESENT.equals(action)) {
78                mUserPresent = true;
79                updateRunning(false);
80            }
81        }
82    };
83
84    @Override
85    protected void onAttachedToWindow() {
86        super.onAttachedToWindow();
87
88        // Listen for broadcasts related to user-presence
89        final IntentFilter filter = new IntentFilter();
90        filter.addAction(Intent.ACTION_SCREEN_OFF);
91        filter.addAction(Intent.ACTION_USER_PRESENT);
92
93        // OK, this is gross but needed. This class is supported by the
94        // remote views machanism and as a part of that the remote views
95        // can be inflated by a context for another user without the app
96        // having interact users permission - just for loading resources.
97        // For exmaple, when adding widgets from a user profile to the
98        // home screen. Therefore, we register the receiver as the current
99        // user not the one the context is for.
100        getContext().registerReceiverAsUser(mReceiver, android.os.Process.myUserHandle(),
101                filter, null, mHandler);
102
103        if (mAutoStart) {
104            // Automatically start when requested
105            startFlipping();
106        }
107    }
108
109    @Override
110    protected void onDetachedFromWindow() {
111        super.onDetachedFromWindow();
112        mVisible = false;
113
114        getContext().unregisterReceiver(mReceiver);
115        updateRunning();
116    }
117
118    @Override
119    protected void onWindowVisibilityChanged(int visibility) {
120        super.onWindowVisibilityChanged(visibility);
121        mVisible = visibility == VISIBLE;
122        updateRunning(false);
123    }
124
125    /**
126     * How long to wait before flipping to the next view
127     *
128     * @param milliseconds
129     *            time in milliseconds
130     */
131    @android.view.RemotableViewMethod
132    public void setFlipInterval(int milliseconds) {
133        mFlipInterval = milliseconds;
134    }
135
136    /**
137     * Start a timer to cycle through child views
138     */
139    public void startFlipping() {
140        mStarted = true;
141        updateRunning();
142    }
143
144    /**
145     * No more flips
146     */
147    public void stopFlipping() {
148        mStarted = false;
149        updateRunning();
150    }
151
152    @Override
153    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
154        super.onInitializeAccessibilityEvent(event);
155        event.setClassName(ViewFlipper.class.getName());
156    }
157
158    @Override
159    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
160        super.onInitializeAccessibilityNodeInfo(info);
161        info.setClassName(ViewFlipper.class.getName());
162    }
163
164    /**
165     * Internal method to start or stop dispatching flip {@link Message} based
166     * on {@link #mRunning} and {@link #mVisible} state.
167     */
168    private void updateRunning() {
169        updateRunning(true);
170    }
171
172    /**
173     * Internal method to start or stop dispatching flip {@link Message} based
174     * on {@link #mRunning} and {@link #mVisible} state.
175     *
176     * @param flipNow Determines whether or not to execute the animation now, in
177     *            addition to queuing future flips. If omitted, defaults to
178     *            true.
179     */
180    private void updateRunning(boolean flipNow) {
181        boolean running = mVisible && mStarted && mUserPresent;
182        if (running != mRunning) {
183            if (running) {
184                showOnly(mWhichChild, flipNow);
185                Message msg = mHandler.obtainMessage(FLIP_MSG);
186                mHandler.sendMessageDelayed(msg, mFlipInterval);
187            } else {
188                mHandler.removeMessages(FLIP_MSG);
189            }
190            mRunning = running;
191        }
192        if (LOGD) {
193            Log.d(TAG, "updateRunning() mVisible=" + mVisible + ", mStarted=" + mStarted
194                    + ", mUserPresent=" + mUserPresent + ", mRunning=" + mRunning);
195        }
196    }
197
198    /**
199     * Returns true if the child views are flipping.
200     */
201    public boolean isFlipping() {
202        return mStarted;
203    }
204
205    /**
206     * Set if this view automatically calls {@link #startFlipping()} when it
207     * becomes attached to a window.
208     */
209    public void setAutoStart(boolean autoStart) {
210        mAutoStart = autoStart;
211    }
212
213    /**
214     * Returns true if this view automatically calls {@link #startFlipping()}
215     * when it becomes attached to a window.
216     */
217    public boolean isAutoStart() {
218        return mAutoStart;
219    }
220
221    private final int FLIP_MSG = 1;
222
223    private final Handler mHandler = new Handler() {
224        @Override
225        public void handleMessage(Message msg) {
226            if (msg.what == FLIP_MSG) {
227                if (mRunning) {
228                    showNext();
229                    msg = obtainMessage(FLIP_MSG);
230                    sendMessageDelayed(msg, mFlipInterval);
231                }
232            }
233        }
234    };
235}
236