利用Android的Canvas绘制正弦函数图像

package com.zhaofeng.main;

import javax.crypto.SealedObject;

import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.os.Bundle;
import android.os.Handler;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;

public class MainView extends Activity {
/** Called when the activity is first created. */

private SurfaceView surfaceView;
private Paint paint;
private SurfaceHolder surfaceHolder;
private int scale_x = 20;
private int scale_y = 50;
private double ox=10;
private double oy=240;
private double x=0;
private double y=0;
private double t=0;
private boolean flag=true;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

surfaceView = (SurfaceView) findViewById(R.id.main_suf);
surfaceHolder = surfaceView.getHolder();

paint = new Paint();

surfaceHolder.addCallback(new Callback() {

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
new Thread(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
while (flag) {
try {
Thread.sleep(10);
Canvas canvas=surfaceHolder.lockCanvas();
if(canvas!=null)
{
//绘制坐标轴
paint.setColor(Color.WHITE);
canvas.drawText("O",20,220, paint);
paint.setColor(Color.BLUE);
canvas.drawLine(10,10,10,480, paint);
canvas.drawText("Y",20,30, paint);
paint.setColor(Color.GREEN);
canvas.drawLine(0,240,320,240, paint);
canvas.drawText("X",300,260, paint);
//绘制正弦曲线
t+=0.1;
x=t*scale_x;
y=Math.sin(t)*scale_y+240;
System.out.println("---------"+Math.round(Math.sin(t)));
if (t>0) {
paint.setColor(Color.RED);
canvas.drawLine(10+(int)ox,(int)oy,10+(int)x,(int)y, paint);
System.out.println(x+"s"+y);
}
ox=x;
oy=y;
if (t>15) {
flag=false;
}
}
surfaceHolder.unlockCanvasAndPost(canvas);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
});
}
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<SurfaceView
android:id="@+id/main_suf"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="@string/hello"
/>
</LinearLayout>