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.view.MotionEvent; 20 import android.view.View; 21 22 /** 23 * OnTouchListener used to shrink the "hit target" of some onscreen buttons. 24 * 25 * We do this for a few specific buttons which are vulnerable to 26 * "false touches" because either (1) they're near the edge of the 27 * screen and might be unintentionally touched while holding the 28 * device in your hand, or (2) they're in the upper corners and might 29 * be touched by the user's ear before the prox sensor has a chance to 30 * kick in. 31 * 32 * TODO (new ICS layout): not sure which buttons need this yet. 33 * For now, use it only with the "End call" button (which extends all 34 * the way to the edges of the screen). But we can consider doing 35 * this for "Dialpad" and/or "Add call" if those turn out to be a 36 * problem too. 37 */ 38 public class SmallerHitTargetTouchListener implements View.OnTouchListener { 39 /** 40 * Width of the allowable "hit target" as a percentage of 41 * the total width of this button. 42 */ 43 private static final int HIT_TARGET_PERCENT_X = 50; 44 45 /** 46 * Height of the allowable "hit target" as a percentage of 47 * the total height of this button. 48 * 49 * This is larger than HIT_TARGET_PERCENT_X because some of 50 * the onscreen buttons are wide but not very tall and we don't 51 * want to make the vertical hit target *too* small. 52 */ 53 private static final int HIT_TARGET_PERCENT_Y = 80; 54 55 // Size (percentage-wise) of the "edge" area that's *not* touch-sensitive. 56 private static final int X_EDGE = (100 - HIT_TARGET_PERCENT_X) / 2; 57 private static final int Y_EDGE = (100 - HIT_TARGET_PERCENT_Y) / 2; 58 // Min/max values (percentage-wise) of the touch-sensitive hit target. 59 private static final int X_HIT_MIN = X_EDGE; 60 private static final int X_HIT_MAX = 100 - X_EDGE; 61 private static final int Y_HIT_MIN = Y_EDGE; 62 private static final int Y_HIT_MAX = 100 - Y_EDGE; 63 64 // True if the most recent DOWN event was a "hit". 65 boolean mDownEventHit; 66 67 /** 68 * Called when a touch event is dispatched to a view. This allows listeners to 69 * get a chance to respond before the target view. 70 * 71 * @return True if the listener has consumed the event, false otherwise. 72 * (In other words, we return true when the touch is *outside* 73 * the "smaller hit target", which will prevent the actual 74 * button from handling these events.) 75 */ 76 @Override onTouch(View v, MotionEvent event)77 public boolean onTouch(View v, MotionEvent event) { 78 // if (DBG) log("SmallerHitTargetTouchListener: " + v + ", event " + event); 79 80 if (event.getAction() == MotionEvent.ACTION_DOWN) { 81 // Note that event.getX() and event.getY() are already 82 // translated into the View's coordinates. (In other words, 83 // "0,0" is a touch on the upper-left-most corner of the view.) 84 int touchX = (int) event.getX(); 85 int touchY = (int) event.getY(); 86 87 int viewWidth = v.getWidth(); 88 int viewHeight = v.getHeight(); 89 90 // Touch location as a percentage of the total button width or height. 91 int touchXPercent = (int) ((float) (touchX * 100) / (float) viewWidth); 92 int touchYPercent = (int) ((float) (touchY * 100) / (float) viewHeight); 93 // if (DBG) log("- percentage: x = " + touchXPercent + ", y = " + touchYPercent); 94 95 // TODO: user research: add event logging here of the actual 96 // hit location (and button ID), and enable it for dogfooders 97 // for a few days. That'll give us a good idea of how close 98 // to the center of the button(s) most touch events are, to 99 // help us fine-tune the HIT_TARGET_PERCENT_* constants. 100 101 if (touchXPercent < X_HIT_MIN || touchXPercent > X_HIT_MAX 102 || touchYPercent < Y_HIT_MIN || touchYPercent > Y_HIT_MAX) { 103 // Missed! 104 // if (DBG) log(" -> MISSED!"); 105 mDownEventHit = false; 106 return true; // Consume this event; don't let the button see it 107 } else { 108 // Hit! 109 // if (DBG) log(" -> HIT!"); 110 mDownEventHit = true; 111 return false; // Let this event through to the actual button 112 } 113 } else { 114 // This is a MOVE, UP or CANCEL event. 115 // 116 // We only do the "smaller hit target" check on DOWN events. 117 // For the subsequent MOVE/UP/CANCEL events, we let them 118 // through to the actual button IFF the previous DOWN event 119 // got through to the actual button (i.e. it was a "hit".) 120 return !mDownEventHit; 121 } 122 } 123 }