package onTouchEvent;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.view.MotionEvent;

import android.view.View;

public class MyView extends View {

    private int textX=,textY=;

    public MyView(Context context) {

    super(context);

    setFocusable(true);

        // TODO Auto-generated constructor stub

    }

        //画笔onDraw方法

    @Override

    protected void onDraw(Canvas canvas) {

        // TODO Auto-generated method stub

        super.onDraw(canvas);

        //初始化画笔

        Paint paint=new Paint();

        //设置颜色

        paint.setColor(Color.GREEN);

        //设置字体大小

        paint.setTextSize();

        //在画布上写文字

        canvas.drawText("Android", textX, textY, paint);

    }

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        // TODO Auto-generated method stub

        //获取用户手指触屏的X坐标赋值与文本的X坐标

        textX=(int)event.getX();

        //获取用户手指触屏的Y坐标赋值与文本的Y坐标

        textY=(int)event.getY();

        //重绘画布

        invalidate();

        return true;

    }

}

setContentView(new MyView(this));

package com.example.cdp;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.view.MotionEvent;

import android.view.SurfaceHolder;

import android.view.SurfaceHolder.Callback;

import android.view.SurfaceView;

public class MySurfaceView extends SurfaceView implements Callback {

    //定义一个SurfaceHolder相当于选择器

    private SurfaceHolder sfh;

    private int textX=,textY=;

    public MySurfaceView(Context context) {

    super(context);

    // TODO Auto-generated constructor stub

    //获得SurfaceHolder对象

    sfh = getHolder();

    //监听surface的生命周期

    sfh.addCallback(this);

    //获得焦点

    setFocusableInTouchMode(true);

    }

    @Override

    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {

        // TODO Auto-generated method stub

    }

    @Override

    public void surfaceCreated(SurfaceHolder arg0) {

        // TODO Auto-generated method stub

        myDraw();

    }

    private void myDraw() {

        // TODO Auto-generated method stub

        new Thread(){

            public void run() {

                // 通过SurfaceHolder对象获得 Surface的Canvas成员变量,并且锁住Canvas

                Canvas canvas = sfh.lockCanvas();

                // 刷屏

                canvas.drawColor(Color.BLACK);

                // 初始画笔

                Paint paint = new Paint();

                // 设置抗锯齿,文字清晰点,不过相对比较耗性能

                paint.setAntiAlias(true);

                // 设置画笔颜色

                paint.setColor(Color.RED);

                // 设置文字大小

                paint.setTextSize();

                // 画（写）文字

                canvas.drawText("Android", textX, textY, paint);

                // 画完后，再将缓存的内容渲染到屏幕上，同时也是解锁

                sfh.unlockCanvasAndPost(canvas);

            };

        }.start();

    }

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        // TODO Auto-generated method stub

        //return super.onTouchEvent(event);

        // 获取用户手指触屏的X坐标赋值与文本的X坐标

        textX = (int) event.getX();

        // 获取用户手指触屏的Y坐标赋值与文本的Y坐标

        textY = (int) event.getY();

        myDraw();

        return true;

    }

    @Override

    public void surfaceDestroyed(SurfaceHolder arg0) {

        // TODO Auto-generated method stub

    }

}