Android:多點觸控偵測以及螢幕觸控事件監聽

package com.example.my_touch1;

import ....
public class MainActivity extends Activity {
LinearLayout layout;
TextView msg;
private StringBuilder data;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        layout=(LinearLayout)findViewById(R.id.rootlayout);
        msg=(TextView)findViewById(R.id.textView1);
        data=new StringBuilder();
        //註冊觸控監聽物件
        layout.setOnTouchListener(new MytouchListener());
    }
   //觸控監聽物件之類別，需實作OnTouchListener
   private class MytouchListener implements OnTouchListener{
   //實作OnTouchListener所需實作之方法
public boolean onTouch(View view, MotionEvent event) {
// 判斷觸控事件
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
data.delete(0, data.length());
msg.setText(data.append("Action down"+"("+event.getX()+","+event.getY()+")"+"\n"));
break;
case MotionEvent.ACTION_UP:
msg.setText(data.append("Action up"+"("+event.getX()+","+event.getY()+")"+"\n"));
break;
case MotionEvent.ACTION_MOVE:
msg.setText(data.append("Action move"+"("+event.getX()+","+event.getY()+")"+"\n"));
break;
}
//取得多點觸控的點數
int pCount=event.getPointerCount();
data.append("多點觸控點數為:"+pCount+"\n");
for(int i=0;i<pCount;i++){
//(event.getX(0),event.getY(0))代表第一點觸控點之座標
data.append(String.format("觸控點%d:(%.2f,%.2f)%n",
                                                                   event.getPointerId(i),event.getX(i),event.getY(i)));

}
msg.setText(data);
return true;
}

   }
}