1 /* 2 * Copyright 2018 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 package androidx.fragment.app; 17 18 import android.animation.Animator; 19 import android.graphics.Rect; 20 import android.transition.Transition; 21 import android.transition.TransitionValues; 22 import android.view.View; 23 import android.view.ViewGroup; 24 25 import java.util.ArrayList; 26 27 /** 28 * A transition that tracks which targets are applied to it. 29 * It will assume any target that it applies to will have differences 30 * between the start and end state, regardless of the differences 31 * that actually exist. In other words, it doesn't actually check 32 * any size or position differences or any other property of the view. 33 * It just records the difference. 34 * <p> 35 * Both start and end value Views are recorded, but no actual animation 36 * is created. 37 */ 38 class TrackingTransition extends Transition implements TargetTracking { 39 public final ArrayList<View> targets = new ArrayList<>(); 40 private final Rect[] mEpicenter = new Rect[1]; 41 private static final String PROP = "tracking:prop"; 42 private static final String[] PROPS = { PROP }; 43 44 @Override 45 public String[] getTransitionProperties() { 46 return PROPS; 47 } 48 49 @Override 50 public void captureStartValues(TransitionValues transitionValues) { 51 transitionValues.values.put(PROP, 0); 52 } 53 54 @Override 55 public void captureEndValues(TransitionValues transitionValues) { 56 transitionValues.values.put(PROP, 1); 57 } 58 59 @Override 60 public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues, 61 TransitionValues endValues) { 62 if (startValues != null) { 63 targets.add(startValues.view); 64 } 65 if (endValues != null) { 66 targets.add(endValues.view); 67 } 68 Rect epicenter = getEpicenter(); 69 if (epicenter != null) { 70 mEpicenter[0] = new Rect(epicenter); 71 } else { 72 mEpicenter[0] = null; 73 } 74 return null; 75 } 76 77 @Override 78 public ArrayList<View> getTrackedTargets() { 79 return targets; 80 } 81 82 @Override 83 public void clearTargets() { 84 targets.clear(); 85 } 86 87 @Override 88 public Rect getCapturedEpicenter() { 89 return mEpicenter[0]; 90 } 91 } 92
