MotionEventCompat.java revision dc5487a46b75572fa9120b22e89487c0178ff0a0
1/* 2 * Copyright (C) 2011 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.support.v4.view; 18 19import android.view.MotionEvent; 20import android.view.View; 21 22/** 23 * Helper for accessing features in {@link MotionEvent} introduced 24 * after API level 4 in a backwards compatible fashion. 25 */ 26public class MotionEventCompat { 27 /** 28 * Interface for the full API. 29 */ 30 interface MotionEventVersionImpl { 31 public int findPointerIndex(MotionEvent event, int pointerId); 32 public int getPointerId(MotionEvent event, int pointerIndex); 33 public float getX(MotionEvent event, int pointerIndex); 34 public float getY(MotionEvent event, int pointerIndex); 35 } 36 37 /** 38 * Interface implementation that doesn't use anything about v4 APIs. 39 */ 40 static class BaseMotionEventVersionImpl implements MotionEventVersionImpl { 41 @Override 42 public int findPointerIndex(MotionEvent event, int pointerId) { 43 if (pointerId == 0) { 44 // id 0 == index 0 and vice versa. 45 return 0; 46 } 47 return -1; 48 } 49 @Override 50 public int getPointerId(MotionEvent event, int pointerIndex) { 51 if (pointerIndex == 0) { 52 // index 0 == id 0 and vice versa. 53 return 0; 54 } 55 throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers"); 56 } 57 @Override 58 public float getX(MotionEvent event, int pointerIndex) { 59 if (pointerIndex == 0) { 60 return event.getX(); 61 } 62 throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers"); 63 } 64 @Override 65 public float getY(MotionEvent event, int pointerIndex) { 66 if (pointerIndex == 0) { 67 return event.getY(); 68 } 69 throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers"); 70 } 71 } 72 73 /** 74 * Interface implementation for devices with at least v11 APIs. 75 */ 76 static class EclairMotionEventVersionImpl implements MotionEventVersionImpl { 77 @Override 78 public int findPointerIndex(MotionEvent event, int pointerId) { 79 return MotionEventCompatEclair.findPointerIndex(event, pointerId); 80 } 81 @Override 82 public int getPointerId(MotionEvent event, int pointerIndex) { 83 return MotionEventCompatEclair.getPointerId(event, pointerIndex); 84 } 85 @Override 86 public float getX(MotionEvent event, int pointerIndex) { 87 return MotionEventCompatEclair.getX(event, pointerIndex); 88 } 89 @Override 90 public float getY(MotionEvent event, int pointerIndex) { 91 return MotionEventCompatEclair.getY(event, pointerIndex); 92 } 93 } 94 95 /** 96 * Select the correct implementation to use for the current platform. 97 */ 98 static final MotionEventVersionImpl IMPL; 99 static { 100 if (android.os.Build.VERSION.SDK_INT >= 5) { 101 IMPL = new EclairMotionEventVersionImpl(); 102 } else { 103 IMPL = new BaseMotionEventVersionImpl(); 104 } 105 } 106 107 // ------------------------------------------------------------------- 108 109 /** 110 * Synonym for {@link MotionEvent#ACTION_MASK}. 111 */ 112 public static final int ACTION_MASK = 0xff; 113 114 /** 115 * Synonym for {@link MotionEvent#ACTION_POINTER_DOWN}. 116 */ 117 public static final int ACTION_POINTER_DOWN = 5; 118 119 /** 120 * Synonym for {@link MotionEvent#ACTION_POINTER_UP}. 121 */ 122 public static final int ACTION_POINTER_UP = 6; 123 124 /** 125 * Synonym for {@link MotionEvent#ACTION_HOVER_MOVE}. 126 */ 127 public static final int ACTION_HOVER_MOVE = 7; 128 129 /** 130 * Synonym for {@link MotionEvent#ACTION_SCROLL}. 131 */ 132 public static final int ACTION_SCROLL = 8; 133 134 /** 135 * Synonym for {@link MotionEvent#ACTION_POINTER_INDEX_MASK}. 136 */ 137 public static final int ACTION_POINTER_INDEX_MASK = 0xff00; 138 139 /** 140 * Synonym for {@link MotionEvent#ACTION_POINTER_INDEX_SHIFT}. 141 */ 142 public static final int ACTION_POINTER_INDEX_SHIFT = 8; 143 144 /** 145 * Constant for {@link #getActionMasked}: The pointer is not down but has entered the 146 * boundaries of a window or view. 147 * <p> 148 * This action is always delivered to the window or view under the pointer. 149 * </p><p> 150 * This action is not a touch event so it is delivered to 151 * {@link View#onGenericMotionEvent(MotionEvent)} rather than 152 * {@link View#onTouchEvent(MotionEvent)}. 153 * </p> 154 */ 155 public static final int ACTION_HOVER_ENTER = 9; 156 157 /** 158 * Constant for {@link #getActionMasked}: The pointer is not down but has exited the 159 * boundaries of a window or view. 160 * <p> 161 * This action is always delivered to the window or view that was previously under the pointer. 162 * </p><p> 163 * This action is not a touch event so it is delivered to 164 * {@link View#onGenericMotionEvent(MotionEvent)} rather than 165 * {@link View#onTouchEvent(MotionEvent)}. 166 * </p> 167 */ 168 public static final int ACTION_HOVER_EXIT = 10; 169 170 /** 171 * Call {@link MotionEvent#getAction}, returning only the {@link #ACTION_MASK} 172 * portion. 173 */ 174 public static int getActionMasked(MotionEvent event) { 175 return event.getAction() & ACTION_MASK; 176 } 177 178 /** 179 * Call {@link MotionEvent#getAction}, returning only the pointer index 180 * portion 181 */ 182 public static int getActionIndex(MotionEvent event) { 183 return (event.getAction() & ACTION_POINTER_INDEX_MASK) 184 >> ACTION_POINTER_INDEX_SHIFT; 185 } 186 187 /** 188 * Call {@link MotionEvent#findPointerIndex(int)}. 189 * If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device, 190 * does nothing and returns -1. 191 */ 192 public static int findPointerIndex(MotionEvent event, int pointerId) { 193 return IMPL.findPointerIndex(event, pointerId); 194 } 195 196 /** 197 * Call {@link MotionEvent#getPointerId(int)}. 198 * If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device, 199 * {@link IndexOutOfBoundsException} is thrown. 200 */ 201 public static int getPointerId(MotionEvent event, int pointerIndex) { 202 return IMPL.getPointerId(event, pointerIndex); 203 } 204 205 /** 206 * Call {@link MotionEvent#getX(int)}. 207 * If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device, 208 * {@link IndexOutOfBoundsException} is thrown. 209 */ 210 public static float getX(MotionEvent event, int pointerIndex) { 211 return IMPL.getX(event, pointerIndex); 212 } 213 214 /** 215 * Call {@link MotionEvent#getY(int)}. 216 * If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device, 217 * {@link IndexOutOfBoundsException} is thrown. 218 */ 219 public static float getY(MotionEvent event, int pointerIndex) { 220 return IMPL.getY(event, pointerIndex); 221 } 222} 223