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      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 
     17 package android.transition;
     18 
     19 import android.content.Context;
     20 import android.content.res.Resources;
     21 import android.content.res.TypedArray;
     22 import android.content.res.XmlResourceParser;
     23 import android.util.AttributeSet;
     24 import android.util.Xml;
     25 import android.view.InflateException;
     26 import android.view.ViewGroup;
     27 import android.view.animation.AnimationUtils;
     28 import org.xmlpull.v1.XmlPullParser;
     29 import org.xmlpull.v1.XmlPullParserException;
     30 
     31 import java.io.IOException;
     32 import java.util.ArrayList;
     33 
     34 /**
     35  * This class inflates scenes and transitions from resource files.
     36  *
     37  * Information on XML resource descriptions for transitions can be found for
     38  * {@link android.R.styleable#Transition}, {@link android.R.styleable#TransitionSet},
     39  * {@link android.R.styleable#TransitionTarget}, {@link android.R.styleable#Fade},
     40  * and {@link android.R.styleable#TransitionManager}.
     41  */
     42 public class TransitionInflater {
     43 
     44     private Context mContext;
     45 
     46     private TransitionInflater(Context context) {
     47         mContext = context;
     48     }
     49 
     50     /**
     51      * Obtains the TransitionInflater from the given context.
     52      */
     53     public static TransitionInflater from(Context context) {
     54         return new TransitionInflater(context);
     55     }
     56 
     57     /**
     58      * Loads a {@link Transition} object from a resource
     59      *
     60      * @param resource The resource id of the transition to load
     61      * @return The loaded Transition object
     62      * @throws android.content.res.Resources.NotFoundException when the
     63      * transition cannot be loaded
     64      */
     65     public Transition inflateTransition(int resource) {
     66         XmlResourceParser parser =  mContext.getResources().getXml(resource);
     67         try {
     68             return createTransitionFromXml(parser, Xml.asAttributeSet(parser), null);
     69         } catch (XmlPullParserException e) {
     70             InflateException ex = new InflateException(e.getMessage());
     71             ex.initCause(e);
     72             throw ex;
     73         } catch (IOException e) {
     74             InflateException ex = new InflateException(
     75                     parser.getPositionDescription()
     76                             + ": " + e.getMessage());
     77             ex.initCause(e);
     78             throw ex;
     79         } finally {
     80             parser.close();
     81         }
     82     }
     83 
     84     /**
     85      * Loads a {@link TransitionManager} object from a resource
     86      *
     87      *
     88      *
     89      * @param resource The resource id of the transition manager to load
     90      * @return The loaded TransitionManager object
     91      * @throws android.content.res.Resources.NotFoundException when the
     92      * transition manager cannot be loaded
     93      */
     94     public TransitionManager inflateTransitionManager(int resource, ViewGroup sceneRoot) {
     95         XmlResourceParser parser =  mContext.getResources().getXml(resource);
     96         try {
     97             return createTransitionManagerFromXml(parser, Xml.asAttributeSet(parser), sceneRoot);
     98         } catch (XmlPullParserException e) {
     99             InflateException ex = new InflateException(e.getMessage());
    100             ex.initCause(e);
    101             throw ex;
    102         } catch (IOException e) {
    103             InflateException ex = new InflateException(
    104                     parser.getPositionDescription()
    105                             + ": " + e.getMessage());
    106             ex.initCause(e);
    107             throw ex;
    108         } finally {
    109             parser.close();
    110         }
    111     }
    112 
    113     //
    114     // Transition loading
    115     //
    116 
    117     private Transition createTransitionFromXml(XmlPullParser parser,
    118             AttributeSet attrs, TransitionSet transitionSet)
    119             throws XmlPullParserException, IOException {
    120 
    121         Transition transition = null;
    122 
    123         // Make sure we are on a start tag.
    124         int type;
    125         int depth = parser.getDepth();
    126 
    127         while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
    128                 && type != XmlPullParser.END_DOCUMENT) {
    129 
    130             boolean newTransition = false;
    131 
    132             if (type != XmlPullParser.START_TAG) {
    133                 continue;
    134             }
    135 
    136             String  name = parser.getName();
    137             if ("fade".equals(name)) {
    138                 TypedArray a = mContext.obtainStyledAttributes(attrs,
    139                         com.android.internal.R.styleable.Fade);
    140                 int fadingMode = a.getInt(com.android.internal.R.styleable.Fade_fadingMode,
    141                         Fade.IN | Fade.OUT);
    142                 transition = new Fade(fadingMode);
    143                 newTransition = true;
    144             } else if ("changeBounds".equals(name)) {
    145                 transition = new ChangeBounds();
    146                 newTransition = true;
    147             } else if ("slide".equals(name)) {
    148                 transition = new Slide();
    149                 newTransition = true;
    150             } else if ("autoTransition".equals(name)) {
    151                 transition = new AutoTransition();
    152                 newTransition = true;
    153             } else if ("recolor".equals(name)) {
    154                 transition = new Recolor();
    155                 newTransition = true;
    156             } else if ("transitionSet".equals(name)) {
    157                 transition = new TransitionSet();
    158                 TypedArray a = mContext.obtainStyledAttributes(attrs,
    159                         com.android.internal.R.styleable.TransitionSet);
    160                 int ordering = a.getInt(
    161                         com.android.internal.R.styleable.TransitionSet_transitionOrdering,
    162                         TransitionSet.ORDERING_TOGETHER);
    163                 ((TransitionSet) transition).setOrdering(ordering);
    164                 createTransitionFromXml(parser, attrs, ((TransitionSet) transition));
    165                 a.recycle();
    166                 newTransition = true;
    167             } else if ("targets".equals(name)) {
    168                 if (parser.getDepth() - 1 > depth && transition != null) {
    169                     // We're inside the child tag - add targets to the child
    170                     getTargetIds(parser, attrs, transition);
    171                 } else if (parser.getDepth() - 1 == depth && transitionSet != null) {
    172                     // add targets to the set
    173                     getTargetIds(parser, attrs, transitionSet);
    174                 }
    175             }
    176             if (transition != null || "targets".equals(name)) {
    177                 if (newTransition) {
    178                     loadTransition(transition, attrs);
    179                     if (transitionSet != null) {
    180                         transitionSet.addTransition(transition);
    181                     }
    182                 }
    183             } else {
    184                 throw new RuntimeException("Unknown scene name: " + parser.getName());
    185             }
    186         }
    187 
    188         return transition;
    189     }
    190 
    191     private void getTargetIds(XmlPullParser parser,
    192             AttributeSet attrs, Transition transition) throws XmlPullParserException, IOException {
    193 
    194         // Make sure we are on a start tag.
    195         int type;
    196         int depth = parser.getDepth();
    197 
    198         ArrayList<Integer> targetIds = new ArrayList<Integer>();
    199         while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
    200                 && type != XmlPullParser.END_DOCUMENT) {
    201 
    202             if (type != XmlPullParser.START_TAG) {
    203                 continue;
    204             }
    205 
    206             String  name = parser.getName();
    207             if (name.equals("target")) {
    208                 TypedArray a = mContext.obtainStyledAttributes(attrs,
    209                         com.android.internal.R.styleable.TransitionTarget);
    210                 int id = a.getResourceId(
    211                         com.android.internal.R.styleable.TransitionTarget_targetId, -1);
    212                 if (id >= 0) {
    213                     targetIds.add(id);
    214                 }
    215             } else {
    216                 throw new RuntimeException("Unknown scene name: " + parser.getName());
    217             }
    218         }
    219         int numTargets = targetIds.size();
    220         if (numTargets > 0) {
    221             for (int i = 0; i < numTargets; ++i) {
    222                 transition.addTarget(targetIds.get(i));
    223             }
    224         }
    225     }
    226 
    227     private Transition loadTransition(Transition transition, AttributeSet attrs)
    228             throws Resources.NotFoundException {
    229 
    230         TypedArray a =
    231                 mContext.obtainStyledAttributes(attrs, com.android.internal.R.styleable.Transition);
    232         long duration = a.getInt(com.android.internal.R.styleable.Transition_duration, -1);
    233         if (duration >= 0) {
    234             transition.setDuration(duration);
    235         }
    236         long startDelay = a.getInt(com.android.internal.R.styleable.Transition_startDelay, -1);
    237         if (startDelay > 0) {
    238             transition.setStartDelay(startDelay);
    239         }
    240         final int resID =
    241                 a.getResourceId(com.android.internal.R.styleable.Animator_interpolator, 0);
    242         if (resID > 0) {
    243             transition.setInterpolator(AnimationUtils.loadInterpolator(mContext, resID));
    244         }
    245         a.recycle();
    246         return transition;
    247     }
    248 
    249     //
    250     // TransitionManager loading
    251     //
    252 
    253     private TransitionManager createTransitionManagerFromXml(XmlPullParser parser,
    254             AttributeSet attrs, ViewGroup sceneRoot) throws XmlPullParserException, IOException {
    255 
    256         // Make sure we are on a start tag.
    257         int type;
    258         int depth = parser.getDepth();
    259         TransitionManager transitionManager = null;
    260 
    261         while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
    262                 && type != XmlPullParser.END_DOCUMENT) {
    263 
    264             if (type != XmlPullParser.START_TAG) {
    265                 continue;
    266             }
    267 
    268             String  name = parser.getName();
    269             if (name.equals("transitionManager")) {
    270                 transitionManager = new TransitionManager();
    271             } else if (name.equals("transition") && (transitionManager != null)) {
    272                 loadTransition(attrs, sceneRoot, transitionManager);
    273             } else {
    274                 throw new RuntimeException("Unknown scene name: " + parser.getName());
    275             }
    276         }
    277         return transitionManager;
    278     }
    279 
    280     private void loadTransition(AttributeSet attrs, ViewGroup sceneRoot,
    281             TransitionManager transitionManager) throws Resources.NotFoundException {
    282 
    283         TypedArray a = mContext.obtainStyledAttributes(attrs,
    284                 com.android.internal.R.styleable.TransitionManager);
    285         int transitionId = a.getResourceId(
    286                 com.android.internal.R.styleable.TransitionManager_transition, -1);
    287         Scene fromScene = null, toScene = null;
    288         int fromId = a.getResourceId(
    289                 com.android.internal.R.styleable.TransitionManager_fromScene, -1);
    290         if (fromId >= 0) fromScene = Scene.getSceneForLayout(sceneRoot, fromId, mContext);
    291         int toId = a.getResourceId(
    292                 com.android.internal.R.styleable.TransitionManager_toScene, -1);
    293         if (toId >= 0) toScene = Scene.getSceneForLayout(sceneRoot, toId, mContext);
    294         if (transitionId >= 0) {
    295             Transition transition = inflateTransition(transitionId);
    296             if (transition != null) {
    297                 if (fromScene != null) {
    298                     if (toScene == null){
    299                         throw new RuntimeException("No matching toScene for given fromScene " +
    300                                 "for transition ID " + transitionId);
    301                     } else {
    302                         transitionManager.setTransition(fromScene, toScene, transition);
    303                     }
    304                 } else if (toId >= 0) {
    305                     transitionManager.setTransition(toScene, transition);
    306                 }
    307             }
    308         }
    309         a.recycle();
    310     }
    311 }
    312