1 import android.app.Activity; 2 import android.os.Bundle; 3 import android.view.MotionEvent; 4 import android.view.View; 5 import android.widget.FrameLayout; 6 import android.widget.FrameLayout.LayoutParams; 7 import android.widget.ImageView; 8  9 public class MainActivity extends Activity {10     11     private ImageView iv;12     private FrameLayout root;13 14     @Override15     protected void onCreate(Bundle savedInstanceState) {16         super.onCreate(savedInstanceState);17         setContentView(R.layout.activity_main);18 19         root = (FrameLayout) findViewById(R.id.container);20         iv = (ImageView) findViewById(R.id.iv);21 22         root.setOnTouchListener(new View.OnTouchListener() {23 24             float currentDistance;25             float lastDistance = -1; // 记录最有一次所记录的值26 27             @Override28             public boolean onTouch(View v, MotionEvent event) {29 30                 switch (event.getAction()) {31                 case MotionEvent.ACTION_DOWN: // 触摸按下32                     System.out.println("action down");33                     break;34                 case MotionEvent.ACTION_MOVE: // 触摸移动35                     // System.out.println("action move");36                     System.out.println("触摸点个数：" + event.getPointerCount());37 38                     if (event.getPointerCount() >= 2) { // 判断大于等于两个触摸点39 40                         float offsetX = event.getX(0) - event.getX(1);41                         float offsetY = event.getY(0) - event.getY(1);42                         // 计算出两个点之间的距离43                         currentDistance = (float) Math.sqrt(offsetX * offsetX44                                 + offsetY * offsetY);45 46                         if (lastDistance < 0) { // 初始值47                             lastDistance = currentDistance;48                         } else {49                             // 当前距离比上次距离>5个像素，可以识别为放大。50                             if (currentDistance - lastDistance > 5) { 51                                 System.out.println("放大");52 53                                 FrameLayout.LayoutParams lp = (LayoutParams) iv54                                         .getLayoutParams();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 64                                 FrameLayout.LayoutParams lp = (LayoutParams) iv65                                         .getLayoutParams();66                                 lp.width = (int) (0.9f * iv.getWidth());67                                 lp.height = (int) (0.9f * iv.getHeight());68 69                                 iv.setLayoutParams(lp);70 71                                 lastDistance = currentDistance;72                             }73                         }74                     }75                     break;76                 case MotionEvent.ACTION_UP: // 触摸弹起77                     // System.out.println("action up");78                     break;79                 }80 81                 return true;82             }83         });84     }85 86 }

 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.jikexueyuan.multouch.MainActivity" 7     tools:ignore="MergeRootFrame" > 8  9     <ImageView10         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>