1 package com.itheima.touch;
2
3 import android.app.Activity;
4 import android.graphics.Matrix;
5 import android.graphics.PointF;
6 import android.os.Bundle;
7 import android.view.MotionEvent;
8 import android.view.View;
9 import android.view.View.OnTouchListener;
10 import android.widget.ImageView;
11
12 public class MainActivity extends Activity {
13
14 private ImageView imageView;
15
16 @Override
17 protected void onCreate(Bundle savedInstanceState) {
18 super.onCreate(savedInstanceState);
19 setContentView(R.layout.activity_main);
20
21 imageView = (ImageView) findViewById(R.id.imageView);
22 imageView.setOnTouchListener(new MyOnTouchListener()); // 添加触摸监听器
23 }
24
25 private class MyOnTouchListener implements OnTouchListener {
26 private float x; // 图片移动前的x轴坐标
27 private float y; // 图片移动前的y轴坐标
28 private Matrix newMatrix = new Matrix(); // 用来移动图片的矩阵
29 private Matrix oldMatrix = new Matrix(); // 图片移动前的矩阵
30 private int type; // 操作类型, 一根手指触摸还是两根手指触摸
31 private float start; // 第二根手指按下时的距离
32 private float end; // 两根手指移动后的距离
33 private PointF point; // 放大时的中心点
34
35 public boolean onTouch(View v, MotionEvent event) {
36 switch (event.getAction() & MotionEvent.ACTION_MASK) {
37 case MotionEvent.ACTION_DOWN:
38 type = 1;
39 x = event.getX();
40 y = event.getY();
41 oldMatrix.set(imageView.getImageMatrix());
42 break;
43 case MotionEvent.ACTION_POINTER_DOWN:
44 type = 2;
45 start = countDistance(event); // 计算第二根手指按下时两点之间的距离
46 point = countPoint(event); // 计算中心点
47 oldMatrix.set(imageView.getImageMatrix());
48 break;
49 case MotionEvent.ACTION_MOVE:
50 newMatrix.set(oldMatrix);
51 if (type == 1) { // 1根手指触摸
52 newMatrix.postTranslate(event.getX() - x, event.getY() - y);
53 } else { // 2跟手指触摸
54 end = countDistance(event); // 计算结束时距离
55 float scale = end / start; // 计算缩放比例
56 newMatrix.postScale(scale, scale, point.x, point.y); // 对模型进行缩放
57 }
58 break;
59 }
60 imageView.setImageMatrix(newMatrix); // 改变图片
61 return true;
62 }
63 }
64
65 public float countDistance(MotionEvent event) {
66 float a = event.getX(1) - event.getX(0); // x轴距离
67 float b = event.getY(1) - event.getY(0); // y轴距离
68 return (float) Math.sqrt(a * a + b * b); // 勾股定理
69 }
70
71 public PointF countPoint(MotionEvent event) {
72 float x = (event.getX(0) + event.getX(1)) / 2; // x轴中间点
73 float y = (event.getY(0) + event.getY(1)) / 2; // y轴中间点
74 return new PointF(x, y);
75 }
76
77
78 /*
79 private class MyOnTouchListener implements OnTouchListener {
80 private float x;
81 private float y;
82 private Matrix oldMatrix = new Matrix();
83 private Matrix newMatrix = new Matrix(); // 用来操作图片的模型
84
85 public boolean onTouch(View v, MotionEvent event) {
86 switch (event.getAction()) { // 判断触摸动作的类型
87 case MotionEvent.ACTION_DOWN: // 按下时
88 x = event.getX(); // 获取x轴坐标
89 y = event.getY(); // 获取y轴坐标
90 oldMatrix.set(imageView.getImageMatrix()); // 用模型记住图片所在位置
91 break;
92 case MotionEvent.ACTION_MOVE: // 移动时
93 newMatrix.set(oldMatrix); // 用另一个模型记住按下时的位置
94 newMatrix.postTranslate(event.getX() - x, event.getY() - y); // 移动模型
95 break;
96 }
97 imageView.setImageMatrix(newMatrix); // 把图片放到了移动后的模型中
98 return true;
99 }
100 }
101 */
102
103 }
