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10_多点触摸交互处理

　　多点触摸，对图像进行缩放的实例。

 1 package com.example.multitouch;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.view.MotionEvent;
 6 import android.view.View;
 7 import android.view.WindowManager;
 8 import android.widget.FrameLayout;
 9 import android.widget.FrameLayout.LayoutParams;
10 import android.widget.ImageView;
11 
12 public class MainActivity extends Activity {
13 
14     private FrameLayout root;
15     private ImageView iv;
16 
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_main);
21 
22         root = (FrameLayout) findViewById(R.id.container);
23         iv = (ImageView) findViewById(R.id.iv);
24 
25         root.setOnTouchListener(new View.OnTouchListener() {
26 
27             float currentDistance;
28             float lastDistance = -1;
29 
30             FrameLayout.LayoutParams lp = (LayoutParams) iv.getLayoutParams();
31 
32             @Override
33             public boolean onTouch(View v, MotionEvent event) {
34 
35                 switch (event.getAction()) {
36                 case MotionEvent.ACTION_DOWN:
37                     System.out.println("action_down");
38                     break;
39                 case MotionEvent.ACTION_MOVE:
40                     System.out.println("action_move");
41 
42                     if (event.getPointerCount() >= 2) {
43 
44                         float offsetX = event.getX(0) - event.getX(1);
45                         float offsetY = event.getY(0) - event.getY(1);
46                         currentDistance = (float) Math.sqrt(offsetX * offsetX
47                                 + offsetY * offsetY);
48 
49                         if (lastDistance < 0) {
50                             lastDistance = currentDistance;
51                         } else {
52                             if (currentDistance - lastDistance > 5) {
53                                 System.out.println("放大");
54 
55                                 lp.width = (int) (1.1f * iv.getWidth());
56                                 lp.height = (int) (1.1f * iv.getHeight());
57 
58                                 iv.setLayoutParams(lp);
59 
60                                 lastDistance = currentDistance;
61                             } else if (lastDistance - currentDistance > 5) {
62                                 System.out.println("缩小");
63                                 lp.width = (int) (0.9f * iv.getWidth());
64                                 lp.height = (int) (0.9f * iv.getHeight());
65                                 iv.setLayoutParams(lp);
66                                 lastDistance = currentDistance;
67                             }
68                         }
69                     }
70 
71                     // 获取到多个触摸点
72                     // System.out.println("pointer count : " +
73                     // event.getPointerCount() );
74                     // System.out.println(String.format("x1:%f y1:%f",
75                     // event.getX(0),event.getY(0)));
76 
77                     // FrameLayout.LayoutParams lp = (LayoutParams)
78                     // iv.getLayoutParams();
79                     // lp.leftMargin = (int) event.getX();
80                     // lp.topMargin = (int) event.getY();
81                     //
82                     // iv.setLayoutParams(lp);
83                     //
84                     // System.out.println(String.format("x:%f,y:%f",
85                     // event.getX(), event.getY() ));
86                     break;
87                 case MotionEvent.ACTION_UP:
88                     System.out.println("action_up");
89                     break;
90                 }
91 
92                 // 返回true的话，事件才会继续被触发。
93                 return true;
94             }
95         });
96     }
97 }
MainActivity 
 1 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:id="@+id/container"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     tools:context="com.example.multitouch.MainActivity"
 7     tools:ignore="MergeRootFrame" >
 8 
 9     <ImageView
10         android:id="@+id/iv"
11         android:layout_width="wrap_content"
12         android:layout_height="wrap_content"
13         android:src="@drawable/ic_launcher" />
14 
15 </FrameLayout>
activity_main.xml
 1 <?xml version="1.0" encoding="utf-8"?>
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3     package="com.example.multitouch"
 4     android:versionCode="1"
 5     android:versionName="1.0" >
 6 
 7     <uses-sdk
 8         android:minSdkVersion="14"
 9         android:targetSdkVersion="19" />
10 
11     <application
12         android:allowBackup="true"
13         android:icon="@drawable/ic_launcher"
14         android:label="@string/app_name"
15         android:theme="@style/AppTheme" >
16         <activity
17             android:name="com.example.multitouch.MainActivity"
18             android:label="@string/app_name" >
19             <intent-filter>
20                 <action android:name="android.intent.action.MAIN" />
21 
22                 <category android:name="android.intent.category.LAUNCHER" />
23             </intent-filter>
24         </activity>
25     </application>
26 
27 </manifest>
AndroidManifest.xml

 

posted @ 2014-10-31 16:12  Yano_nankai  阅读(157)  评论(0)  编辑  收藏  举报