1 /* 2 * Copyright (C) 2012 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 com.android.phone; 18 19 import android.util.Log; 20 import android.view.MotionEvent; 21 import android.view.View; 22 23 /** 24 * OnTouchListener used to shrink the "hit target" of some onscreen buttons. 25 * 26 * We do this for a few specific buttons which are vulnerable to 27 * "false touches" because either (1) they're near the edge of the 28 * screen and might be unintentionally touched while holding the 29 * device in your hand, (2) they're in the upper corners and might 30 * be touched by the user's ear before the prox sensor has a chance to 31 * kick in, or (3) they are close to other buttons. 32 */ 33 public class SmallerHitTargetTouchListener implements View.OnTouchListener { 34 private static final String TAG = "SmallerHitTargetTouchListener"; 35 36 /** 37 * Edge dimensions where a touch does not register an action (in DIP). 38 */ 39 private static final int HIT_TARGET_EDGE_IGNORE_DP_X = 30; 40 private static final int HIT_TARGET_EDGE_IGNORE_DP_Y = 10; 41 private static final int HIT_TARGET_MIN_SIZE_DP_X = HIT_TARGET_EDGE_IGNORE_DP_X * 3; 42 private static final int HIT_TARGET_MIN_SIZE_DP_Y = HIT_TARGET_EDGE_IGNORE_DP_Y * 3; 43 44 // True if the most recent DOWN event was a "hit". 45 boolean mDownEventHit; 46 47 /** 48 * Called when a touch event is dispatched to a view. This allows listeners to 49 * get a chance to respond before the target view. 50 * 51 * @return True if the listener has consumed the event, false otherwise. 52 * (In other words, we return true when the touch is *outside* 53 * the "smaller hit target", which will prevent the actual 54 * button from handling these events.) 55 */ 56 @Override onTouch(View v, MotionEvent event)57 public boolean onTouch(View v, MotionEvent event) { 58 // if (DBG) log("SmallerHitTargetTouchListener: " + v + ", event " + event); 59 60 if (event.getAction() == MotionEvent.ACTION_DOWN) { 61 // Note that event.getX() and event.getY() are already 62 // translated into the View's coordinates. (In other words, 63 // "0,0" is a touch on the upper-left-most corner of the view.) 64 final int touchX = (int) event.getX(); 65 final int touchY = (int) event.getY(); 66 67 final int viewWidth = v.getWidth(); 68 final int viewHeight = v.getHeight(); 69 70 final float pixelDensity = v.getResources().getDisplayMetrics().density; 71 final int targetMinSizeX = (int) (HIT_TARGET_MIN_SIZE_DP_X * pixelDensity); 72 final int targetMinSizeY = (int) (HIT_TARGET_MIN_SIZE_DP_Y * pixelDensity); 73 74 int edgeIgnoreX = (int) (HIT_TARGET_EDGE_IGNORE_DP_X * pixelDensity); 75 int edgeIgnoreY = (int) (HIT_TARGET_EDGE_IGNORE_DP_Y * pixelDensity); 76 77 // If we are dealing with smaller buttons where the dead zone defined by 78 // HIT_TARGET_EDGE_IGNORE_DP_[X|Y] is too large. 79 if (viewWidth < targetMinSizeX || viewHeight < targetMinSizeY) { 80 // This really should not happen given our two use cases (as of this writing) 81 // in the call edge button and secondary calling card. However, we leave 82 // this is as a precautionary measure. 83 Log.w(TAG, "onTouch: view is too small for SmallerHitTargetTouchListener"); 84 edgeIgnoreX = 0; 85 edgeIgnoreY = 0; 86 } 87 88 final int minTouchX = edgeIgnoreX; 89 final int maxTouchX = viewWidth - edgeIgnoreX; 90 final int minTouchY = edgeIgnoreY; 91 final int maxTouchY = viewHeight - edgeIgnoreY; 92 93 if (touchX < minTouchX || touchX > maxTouchX || 94 touchY < minTouchY || touchY > maxTouchY) { 95 // Missed! 96 // if (DBG) log(" -> MISSED!"); 97 mDownEventHit = false; 98 return true; // Consume this event; don't let the button see it 99 } else { 100 // Hit! 101 // if (DBG) log(" -> HIT!"); 102 mDownEventHit = true; 103 return false; // Let this event through to the actual button 104 } 105 } else { 106 // This is a MOVE, UP or CANCEL event. 107 // 108 // We only do the "smaller hit target" check on DOWN events. 109 // For the subsequent MOVE/UP/CANCEL events, we let them 110 // through to the actual button IFF the previous DOWN event 111 // got through to the actual button (i.e. it was a "hit".) 112 return !mDownEventHit; 113 } 114 } 115 } 116