21天学习android开发教程之SurfaceView

package com.testSurfaceView;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;

public class testSurfaceView extends Activity {
    /** Called when the activity is first created. */
    Button btnSimpleDraw, btnTimerDraw;
    SurfaceView sfv;
    SurfaceHolder sfh;

    private Timer mTimer;
    private MyTimerTask mTimerTask;
    int Y_axis[],//保存正弦波的Y轴上的点
    centerY,//中心线
    oldX,oldY,//上一个XY点 
    currentX;//当前绘制到的X轴上的点

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btnSimpleDraw = (Button) this.findViewById(R.id.Button01);
        btnTimerDraw = (Button) this.findViewById(R.id.Button02);
        btnSimpleDraw.setOnClickListener(new ClickEvent());
        btnTimerDraw.setOnClickListener(new ClickEvent());
        sfv = (SurfaceView) this.findViewById(R.id.SurfaceView01);
        sfh = sfv.getHolder();

        //动态绘制正弦波的定时器
        mTimer = new Timer();
        mTimerTask = new MyTimerTask();

        // 初始化y轴数据
        centerY = (getWindowManager().getDefaultDisplay().getHeight() - sfv
                .getTop()) / 2;
        Y_axis = new int[getWindowManager().getDefaultDisplay().getWidth()];
        for (int i = 1; i