单点触控

TouchEvent.class

package com.bwie.touch;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class TouchEvent extends View {

	public float x=50;//刚进入时小球的位置
	public float y=60;
	public TouchEvent(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}
	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.onDraw(canvas);
		Paint paint=new Paint();
		//设置画笔的颜色
		paint.setColor(Color.CYAN);
		//画一个小球
		canvas.drawCircle(x, y, 20, paint);

	}
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub
		//获得该小球的x,y
		this.x=event.getX();
		this.y=event.getY();
		//通知该组件重绘
		this.invalidate();
		//返回true表明处理方法已经处理该事件
		return true;
	}

}

xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

  <com.bwie.touch.TouchEvent
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      />

</RelativeLayout>