TransitionInflater.java revision f3de5a2e34412710234cd1f5f3933ce266ea0e49 
1/*
2 * Copyright (C) 2013 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.transition;
18
19import com.android.internal.R;
20
21import org.xmlpull.v1.XmlPullParser;
22import org.xmlpull.v1.XmlPullParserException;
23
24import android.content.Context;
25import android.content.res.Resources;
26import android.content.res.TypedArray;
27import android.content.res.XmlResourceParser;
28import android.util.ArrayMap;
29import android.util.AttributeSet;
30import android.util.Xml;
31import android.view.InflateException;
32import android.view.ViewGroup;
33
34import java.io.IOException;
35import java.lang.reflect.Constructor;
36import java.lang.reflect.InvocationTargetException;
37
38/**
39 * This class inflates scenes and transitions from resource files.
40 *
41 * Information on XML resource descriptions for transitions can be found for
42 * {@link android.R.styleable#Transition}, {@link android.R.styleable#TransitionSet},
43 * {@link android.R.styleable#TransitionTarget}, {@link android.R.styleable#Fade},
44 * and {@link android.R.styleable#TransitionManager}.
45 */
46public class TransitionInflater {
47
48    private static final Class<?>[] sConstructorSignature = new Class[] {
49            Context.class, AttributeSet.class};
50    private final static ArrayMap<String, Constructor> sConstructors =
51            new ArrayMap<String, Constructor>();
52
53    private Context mContext;
54
55    private TransitionInflater(Context context) {
56        mContext = context;
57    }
58
59    /**
60     * Obtains the TransitionInflater from the given context.
61     */
62    public static TransitionInflater from(Context context) {
63        return new TransitionInflater(context);
64    }
65
66    /**
67     * Loads a {@link Transition} object from a resource
68     *
69     * @param resource The resource id of the transition to load
70     * @return The loaded Transition object
71     * @throws android.content.res.Resources.NotFoundException when the
72     * transition cannot be loaded
73     */
74    public Transition inflateTransition(int resource) {
75        XmlResourceParser parser =  mContext.getResources().getXml(resource);
76        try {
77            return createTransitionFromXml(parser, Xml.asAttributeSet(parser), null);
78        } catch (XmlPullParserException e) {
79            InflateException ex = new InflateException(e.getMessage());
80            ex.initCause(e);
81            throw ex;
82        } catch (IOException e) {
83            InflateException ex = new InflateException(
84                    parser.getPositionDescription()
85                            + ": " + e.getMessage());
86            ex.initCause(e);
87            throw ex;
88        } finally {
89            parser.close();
90        }
91    }
92
93    /**
94     * Loads a {@link TransitionManager} object from a resource
95     *
96     * @param resource The resource id of the transition manager to load
97     * @return The loaded TransitionManager object
98     * @throws android.content.res.Resources.NotFoundException when the
99     * transition manager cannot be loaded
100     */
101    public TransitionManager inflateTransitionManager(int resource, ViewGroup sceneRoot) {
102        XmlResourceParser parser =  mContext.getResources().getXml(resource);
103        try {
104            return createTransitionManagerFromXml(parser, Xml.asAttributeSet(parser), sceneRoot);
105        } catch (XmlPullParserException e) {
106            InflateException ex = new InflateException(e.getMessage());
107            ex.initCause(e);
108            throw ex;
109        } catch (IOException e) {
110            InflateException ex = new InflateException(
111                    parser.getPositionDescription()
112                            + ": " + e.getMessage());
113            ex.initCause(e);
114            throw ex;
115        } finally {
116            parser.close();
117        }
118    }
119
120    //
121    // Transition loading
122    //
123    private Transition createTransitionFromXml(XmlPullParser parser,
124            AttributeSet attrs, Transition parent)
125            throws XmlPullParserException, IOException {
126
127        Transition transition = null;
128
129        // Make sure we are on a start tag.
130        int type;
131        int depth = parser.getDepth();
132
133        TransitionSet transitionSet = (parent instanceof TransitionSet)
134                ? (TransitionSet) parent : null;
135
136        while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
137                && type != XmlPullParser.END_DOCUMENT) {
138
139            if (type != XmlPullParser.START_TAG) {
140                continue;
141            }
142
143            String  name = parser.getName();
144            if ("fade".equals(name)) {
145                transition = new Fade(mContext, attrs);
146            } else if ("changeBounds".equals(name)) {
147                transition = new ChangeBounds(mContext, attrs);
148            } else if ("slide".equals(name)) {
149                transition = new Slide(mContext, attrs);
150            } else if ("explode".equals(name)) {
151                transition = new Explode(mContext, attrs);
152            } else if ("changeImageTransform".equals(name)) {
153                transition = new ChangeImageTransform(mContext, attrs);
154            } else if ("changeTransform".equals(name)) {
155                transition = new ChangeTransform(mContext, attrs);
156            } else if ("changeClipBounds".equals(name)) {
157                transition = new ChangeClipBounds(mContext, attrs);
158            } else if ("autoTransition".equals(name)) {
159                transition = new AutoTransition(mContext, attrs);
160            } else if ("recolor".equals(name)) {
161                transition = new Recolor(mContext, attrs);
162            } else if ("transitionSet".equals(name)) {
163                transition = new TransitionSet(mContext, attrs);
164            } else if ("transition".equals(name)) {
165                transition = (Transition) createCustom(attrs, Transition.class, "transition");
166            } else if ("targets".equals(name)) {
167                getTargetIds(parser, attrs, parent);
168            } else if ("arcMotion".equals(name)) {
169                parent.setPathMotion(new ArcMotion(mContext, attrs));
170            } else if ("pathMotion".equals(name)) {
171                parent.setPathMotion((PathMotion)createCustom(attrs, PathMotion.class, "pathMotion"));
172            } else if ("patternMotion".equals(name)) {
173                parent.setPathMotion(new PatternMotion(mContext, attrs));
174            } else {
175                throw new RuntimeException("Unknown scene name: " + parser.getName());
176            }
177            if (transition != null) {
178                if (!parser.isEmptyElementTag()) {
179                    createTransitionFromXml(parser, attrs, transition);
180                }
181                if (transitionSet != null) {
182                    transitionSet.addTransition(transition);
183                    transition = null;
184                } else if (parent != null) {
185                    throw new InflateException("Could not add transition to another transition.");
186                }
187            }
188        }
189
190        return transition;
191    }
192
193    private Object createCustom(AttributeSet attrs, Class expectedType, String tag) {
194        String className = attrs.getAttributeValue(null, "class");
195
196        if (className == null) {
197            throw new InflateException(tag + " tag must have a 'class' attribute");
198        }
199
200        try {
201            synchronized (sConstructors) {
202                Constructor constructor = sConstructors.get(className);
203                if (constructor == null) {
204                    Class c = mContext.getClassLoader().loadClass(className)
205                            .asSubclass(expectedType);
206                    if (c != null) {
207                        constructor = c.getConstructor(sConstructorSignature);
208                        sConstructors.put(className, constructor);
209                    }
210                }
211
212                return constructor.newInstance(mContext, attrs);
213            }
214        } catch (InstantiationException e) {
215            throw new InflateException("Could not instantiate " + expectedType + " class " +
216                    className, e);
217        } catch (ClassNotFoundException e) {
218            throw new InflateException("Could not instantiate " + expectedType + " class " +
219                    className, e);
220        } catch (InvocationTargetException e) {
221            throw new InflateException("Could not instantiate " + expectedType + " class " +
222                    className, e);
223        } catch (NoSuchMethodException e) {
224            throw new InflateException("Could not instantiate " + expectedType + " class " +
225                    className, e);
226        } catch (IllegalAccessException e) {
227            throw new InflateException("Could not instantiate " + expectedType + " class " +
228                    className, e);
229        }
230    }
231
232    private void getTargetIds(XmlPullParser parser,
233            AttributeSet attrs, Transition transition) throws XmlPullParserException, IOException {
234
235        // Make sure we are on a start tag.
236        int type;
237        int depth = parser.getDepth();
238
239        while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
240                && type != XmlPullParser.END_DOCUMENT) {
241
242            if (type != XmlPullParser.START_TAG) {
243                continue;
244            }
245
246            String  name = parser.getName();
247            if (name.equals("target")) {
248                TypedArray a = mContext.obtainStyledAttributes(attrs, R.styleable.TransitionTarget);
249                int id = a.getResourceId(R.styleable.TransitionTarget_targetId, 0);
250                String transitionName;
251                if (id != 0) {
252                    transition.addTarget(id);
253                } else if ((id = a.getResourceId(R.styleable.TransitionTarget_excludeId, 0)) != 0) {
254                    transition.excludeTarget(id, true);
255                } else if ((transitionName = a.getString(R.styleable.TransitionTarget_targetName))
256                        != null) {
257                    transition.addTarget(transitionName);
258                } else if ((transitionName = a.getString(R.styleable.TransitionTarget_excludeName))
259                        != null) {
260                    transition.excludeTarget(transitionName, true);
261                } else {
262                    String className = a.getString(R.styleable.TransitionTarget_excludeClass);
263                    try {
264                        if (className != null) {
265                            Class clazz = Class.forName(className);
266                            transition.excludeTarget(clazz, true);
267                        } else if ((className =
268                                a.getString(R.styleable.TransitionTarget_targetClass)) != null) {
269                            Class clazz = Class.forName(className);
270                            transition.addTarget(clazz);
271                        }
272                    } catch (ClassNotFoundException e) {
273                        throw new RuntimeException("Could not create " + className, e);
274                    }
275                }
276            } else {
277                throw new RuntimeException("Unknown scene name: " + parser.getName());
278            }
279        }
280    }
281
282    //
283    // TransitionManager loading
284    //
285
286    private TransitionManager createTransitionManagerFromXml(XmlPullParser parser,
287            AttributeSet attrs, ViewGroup sceneRoot) throws XmlPullParserException, IOException {
288
289        // Make sure we are on a start tag.
290        int type;
291        int depth = parser.getDepth();
292        TransitionManager transitionManager = null;
293
294        while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
295                && type != XmlPullParser.END_DOCUMENT) {
296
297            if (type != XmlPullParser.START_TAG) {
298                continue;
299            }
300
301            String  name = parser.getName();
302            if (name.equals("transitionManager")) {
303                transitionManager = new TransitionManager();
304            } else if (name.equals("transition") && (transitionManager != null)) {
305                loadTransition(attrs, sceneRoot, transitionManager);
306            } else {
307                throw new RuntimeException("Unknown scene name: " + parser.getName());
308            }
309        }
310        return transitionManager;
311    }
312
313    private void loadTransition(AttributeSet attrs, ViewGroup sceneRoot,
314            TransitionManager transitionManager) throws Resources.NotFoundException {
315
316        TypedArray a = mContext.obtainStyledAttributes(attrs, R.styleable.TransitionManager);
317        int transitionId = a.getResourceId(R.styleable.TransitionManager_transition, -1);
318        int fromId = a.getResourceId(R.styleable.TransitionManager_fromScene, -1);
319        Scene fromScene = (fromId < 0) ? null: Scene.getSceneForLayout(sceneRoot, fromId, mContext);
320        int toId = a.getResourceId(R.styleable.TransitionManager_toScene, -1);
321        Scene toScene = (toId < 0) ? null : Scene.getSceneForLayout(sceneRoot, toId, mContext);
322
323        if (transitionId >= 0) {
324            Transition transition = inflateTransition(transitionId);
325            if (transition != null) {
326                if (toScene == null) {
327                    throw new RuntimeException("No toScene for transition ID " + transitionId);
328                }
329                if (fromScene == null) {
330                    transitionManager.setTransition(toScene, transition);
331                } else {
332                    transitionManager.setTransition(fromScene, toScene, transition);
333                }
334            }
335        }
336        a.recycle();
337    }
338}
339