1 /* 2 * Copyright (C) 2014 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 android.transition; 17 18 import android.graphics.Rect; 19 import android.transition.Slide.GravityFlag; 20 import android.view.Gravity; 21 import android.view.View; 22 import android.view.ViewGroup; 23 24 /** 25 * A <code>TransitionPropagation</code> that propagates based on the distance to the side 26 * and, orthogonally, the distance to epicenter. If the transitioning View is visible in 27 * the start of the transition, then it will transition sooner when closer to the side and 28 * later when farther. If the view is not visible in the start of the transition, then 29 * it will transition later when closer to the side and sooner when farther from the edge. 30 * This is the default TransitionPropagation used with {@link android.transition.Slide}. 31 */ 32 public class SidePropagation extends VisibilityPropagation { 33 private static final String TAG = "SlidePropagation"; 34 35 private float mPropagationSpeed = 3.0f; 36 private int mSide = Gravity.BOTTOM; 37 38 /** 39 * Sets the side that is used to calculate the transition propagation. If the transitioning 40 * View is visible in the start of the transition, then it will transition sooner when 41 * closer to the side and later when farther. If the view is not visible in the start of 42 * the transition, then it will transition later when closer to the side and sooner when 43 * farther from the edge. The default is {@link Gravity#BOTTOM}. 44 * 45 * @param side The side that is used to calculate the transition propagation. Must be one of 46 * {@link Gravity#LEFT}, {@link Gravity#TOP}, {@link Gravity#RIGHT}, 47 * {@link Gravity#BOTTOM}, {@link Gravity#START}, or {@link Gravity#END}. 48 */ 49 public void setSide(@GravityFlag int side) { 50 mSide = side; 51 } 52 53 /** 54 * Sets the speed at which transition propagation happens, relative to the duration of the 55 * Transition. A <code>propagationSpeed</code> of 1 means that a View centered at the side 56 * set in {@link #setSide(int)} and View centered at the opposite edge will have a difference 57 * in start delay of approximately the duration of the Transition. A speed of 2 means the 58 * start delay difference will be approximately half of the duration of the transition. A 59 * value of 0 is illegal, but negative values will invert the propagation. 60 * 61 * @param propagationSpeed The speed at which propagation occurs, relative to the duration 62 * of the transition. A speed of 4 means it works 4 times as fast 63 * as the duration of the transition. May not be 0. 64 */ 65 public void setPropagationSpeed(float propagationSpeed) { 66 if (propagationSpeed == 0) { 67 throw new IllegalArgumentException("propagationSpeed may not be 0"); 68 } 69 mPropagationSpeed = propagationSpeed; 70 } 71 72 @Override 73 public long getStartDelay(ViewGroup sceneRoot, Transition transition, 74 TransitionValues startValues, TransitionValues endValues) { 75 if (startValues == null && endValues == null) { 76 return 0; 77 } 78 int directionMultiplier = 1; 79 Rect epicenter = transition.getEpicenter(); 80 TransitionValues positionValues; 81 if (endValues == null || getViewVisibility(startValues) == View.VISIBLE) { 82 positionValues = startValues; 83 directionMultiplier = -1; 84 } else { 85 positionValues = endValues; 86 } 87 88 int viewCenterX = getViewX(positionValues); 89 int viewCenterY = getViewY(positionValues); 90 91 int[] loc = new int[2]; 92 sceneRoot.getLocationOnScreen(loc); 93 int left = loc[0] + Math.round(sceneRoot.getTranslationX()); 94 int top = loc[1] + Math.round(sceneRoot.getTranslationY()); 95 int right = left + sceneRoot.getWidth(); 96 int bottom = top + sceneRoot.getHeight(); 97 98 int epicenterX; 99 int epicenterY; 100 if (epicenter != null) { 101 epicenterX = epicenter.centerX(); 102 epicenterY = epicenter.centerY(); 103 } else { 104 epicenterX = (left + right) / 2; 105 epicenterY = (top + bottom) / 2; 106 } 107 108 float distance = distance(sceneRoot, viewCenterX, viewCenterY, epicenterX, epicenterY, 109 left, top, right, bottom); 110 float maxDistance = getMaxDistance(sceneRoot); 111 float distanceFraction = distance/maxDistance; 112 113 long duration = transition.getDuration(); 114 if (duration < 0) { 115 duration = 300; 116 } 117 118 return Math.round(duration * directionMultiplier / mPropagationSpeed * distanceFraction); 119 } 120 121 private int distance(View sceneRoot, int viewX, int viewY, int epicenterX, int epicenterY, 122 int left, int top, int right, int bottom) { 123 final int side; 124 if (mSide == Gravity.START) { 125 final boolean isRtl = sceneRoot.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL; 126 side = isRtl ? Gravity.RIGHT : Gravity.LEFT; 127 } else if (mSide == Gravity.END) { 128 final boolean isRtl = sceneRoot.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL; 129 side = isRtl ? Gravity.LEFT : Gravity.RIGHT; 130 } else { 131 side = mSide; 132 } 133 int distance = 0; 134 switch (side) { 135 case Gravity.LEFT: 136 distance = right - viewX + Math.abs(epicenterY - viewY); 137 break; 138 case Gravity.TOP: 139 distance = bottom - viewY + Math.abs(epicenterX - viewX); 140 break; 141 case Gravity.RIGHT: 142 distance = viewX - left + Math.abs(epicenterY - viewY); 143 break; 144 case Gravity.BOTTOM: 145 distance = viewY - top + Math.abs(epicenterX - viewX); 146 break; 147 } 148 return distance; 149 } 150 151 private int getMaxDistance(ViewGroup sceneRoot) { 152 switch (mSide) { 153 case Gravity.LEFT: 154 case Gravity.RIGHT: 155 case Gravity.START: 156 case Gravity.END: 157 return sceneRoot.getWidth(); 158 default: 159 return sceneRoot.getHeight(); 160 } 161 } 162 } 163