1 /* 2 * Copyright (C) 2010 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.photoeditor.actions; 18 19 import android.content.Context; 20 import android.util.AttributeSet; 21 import android.view.GestureDetector; 22 import android.view.MotionEvent; 23 import android.view.View; 24 25 /** 26 * A view that detects user gestures and touch motions. 27 */ 28 class TouchView extends View { 29 30 /** 31 * Listener of swipes. 32 */ 33 public interface SwipeListener { 34 onSwipeLeft()35 void onSwipeLeft(); 36 onSwipeRight()37 void onSwipeRight(); 38 onSwipeUp()39 void onSwipeUp(); 40 onSwipeDown()41 void onSwipeDown(); 42 } 43 44 /** 45 * Listener of single tap confirmed (click). 46 */ 47 public interface SingleTapListener { 48 onSingleTap(float x, float y)49 void onSingleTap(float x, float y); 50 } 51 52 private final GestureDetector gestureDetector; 53 54 private SwipeListener swipeListener; 55 private SingleTapListener singleTapListener; 56 TouchView(Context context, AttributeSet attrs)57 public TouchView(Context context, AttributeSet attrs) { 58 super(context, attrs); 59 60 final int swipeThreshold = (int) (500 * getResources().getDisplayMetrics().density); 61 gestureDetector = new GestureDetector( 62 context, new GestureDetector.SimpleOnGestureListener() { 63 64 @Override 65 public boolean onDown(MotionEvent e) { 66 // GestureDetector onTouchEvent returns true for fling events only when their 67 // preceding down events are consumed. 68 return true; 69 } 70 71 @Override 72 public boolean onSingleTapUp(MotionEvent e) { 73 if (singleTapListener != null) { 74 singleTapListener.onSingleTap(e.getX(), e.getY()); 75 } 76 return true; 77 } 78 79 @Override 80 public boolean onFling( 81 MotionEvent me1, MotionEvent me2, float velocityX, float velocityY) { 82 if (swipeListener != null) { 83 float absX = Math.abs(velocityX); 84 float absY = Math.abs(velocityY); 85 float deltaX = me2.getX() - me1.getX(); 86 float deltaY = me2.getY() - me1.getY(); 87 int travelX = getWidth() / 4; 88 int travelY = getHeight() / 4; 89 if (velocityX > swipeThreshold && absY < absX && deltaX > travelX) { 90 swipeListener.onSwipeRight(); 91 } else if (velocityX < -swipeThreshold && absY < absX && deltaX < -travelX) { 92 swipeListener.onSwipeLeft(); 93 } else if (velocityY < -swipeThreshold && absX < absY && deltaY < -travelY) { 94 swipeListener.onSwipeUp(); 95 } else if (velocityY > swipeThreshold && absX < absY / 2 && deltaY > travelY) { 96 swipeListener.onSwipeDown(); 97 } 98 } 99 return true; 100 } 101 }); 102 gestureDetector.setIsLongpressEnabled(false); 103 } 104 setSwipeListener(SwipeListener listener)105 public void setSwipeListener(SwipeListener listener) { 106 swipeListener = listener; 107 } 108 setSingleTapListener(SingleTapListener listener)109 public void setSingleTapListener(SingleTapListener listener) { 110 singleTapListener = listener; 111 } 112 113 @Override onTouchEvent(MotionEvent event)114 public boolean onTouchEvent(MotionEvent event) { 115 return isEnabled() && gestureDetector.onTouchEvent(event); 116 } 117 } 118