如图：

package com.example.myview;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.graphics.Paint.Style;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

import android.view.SurfaceHolder;

import android.view.SurfaceHolder.Callback;

import android.view.SurfaceView;

/**

*

* @author HTP

*

*/

public class MyView extends SurfaceView implements Callback, OnTouchListener {

private Paint p = new Paint();

private Path path = new Path();

public MyView(Context context) {

// TODO Auto-generated constructor stub

super(context);

getHolder().addCallback(this);

p.setColor(Color.RED);

p.setTextSize(20);

p.setStyle(Style.STROKE);

// 设置监听

setOnTouchListener(this);

}

public MyView(Context context, AttributeSet attrs) {

super(context, attrs);

// TODO Auto-generated constructor stub

getHolder().addCallback(this);

p.setColor(Color.RED);

//消除锯齿

p.setAntiAlias(true);

p.setTextSize(20);

p.setStyle(Style.STROKE);

setOnTouchListener(this);

}

/**

* 自定义画的方法canvas.drawPath

*/

public void draw() {

// TODO Auto-generated method stub

Canvas canvas = getHolder().lockCanvas();

canvas.drawColor(Color.WHITE);

canvas.drawPath(path, p);

getHolder().unlockCanvasAndPost(canvas);

}

@Override

public void surfaceChanged(SurfaceHolder holder, int format, int width,

int height) {

// TODO Auto-generated method stub

draw();

}

@Override

public void surfaceCreated(SurfaceHolder holder) {

// TODO Auto-generated method stub

draw();

}

@Override

public void surfaceDestroyed(SurfaceHolder holder) {

// TODO Auto-generated method stub

// draw();

}

/**

* 触摸事件

*/

@Override

public boolean onTouch(View v, MotionEvent event) {

// TODO Auto-generated method stub

switch (event.getAction()) {

case MotionEvent.ACTION_DOWN:

path.moveTo(event.getX(), event.getY());

draw();

break;

case MotionEvent.ACTION_MOVE:

path.lineTo(event.getX(), event.getY());

draw();

break;

default:

break;

}

return true;

}

/**

* 清理画布

*/

public void clear() {

path.reset();

draw();

}

}