android 线程更新绘图Demo

package com.example.testsurfaceviewactivity;

import java.lang.reflect.Field;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;

public class TestsurfaceviewActivity extends Activity {
    private final static String TAG = "TestsurfaceviewActivity";
    
    
    private int mScreenWidth,mScreenHeight;
    private int stp;
    private int mCnt=0;
    
    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        DisplayMetrics metric = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metric);
        mScreenWidth = metric.widthPixels;     // 屏幕宽度（像素）
        mScreenHeight = metric.heightPixels;   // 
        
                
        onHanlderTest();
    }

    private final static int MSG_UPDATE_START  = 1;
    private final static int MSG_UPDATE_STOP   = 2;
    private final static int MSG_UPDATE_REGION = 3;
    private DrawViewer dv = null;
    private myTestThread myDrawThread;
    private Thread th;
    
    private void onHanlderTest(){
        dv = new DrawViewer(this);
//        new Thread(new myTestThread()).start(); 
        
        myDrawThread=new myTestThread();
        th=new Thread(myDrawThread);
        th.start();
        
        this.setContentView(dv); //请务必注意这句，否则其内容将不是画在此DrawViewer上面
    }
    
        
    private class DrawViewer extends View {
        private int center = 0;

        public DrawViewer(Context ctx) {
            super(ctx);
            this.center = 30;
            stp=10;
        }

        @Override
        protected void onDraw(Canvas canvas){
            Log.i(TAG,"onDraw curr position = "+ center);
            center+= 10;
            stp+=10;
            if(stp>=mScreenWidth) stp = 0;
            
            if(center >= 1280) center = 0;
            Paint mPaint = new Paint();  
            mPaint.setAntiAlias(true);  
            mPaint.setColor(Color.RED); 
            mPaint.setAlpha(0x80); 
            canvas.drawCircle(center, 320, 40, mPaint);
            mPaint.setColor(Color.BLUE);
            canvas.drawLine(0, 360, 1280, 360, mPaint);
            
            if(stp==0){
                
                mCnt++;
                if(mCnt>5){
                    mCnt=0;
                }
                
            }
            switch(mCnt){
            case 1://R
                mPaint.setColor(Color.RED);
                break;
            case 2://G
                mPaint.setColor(Color.GREEN);
                break;
            case 3://B
                mPaint.setColor(Color.BLUE);
                break;
            case 4://W
                mPaint.setColor(Color.WHITE);
                this.setBackgroundColor(Color.BLACK);
                break;
            case 5://B
                mPaint.setColor(Color.BLACK);
                this.setBackgroundColor(Color.WHITE);
                canvas.drawText("lcd end...",mScreenWidth/2 , mScreenHeight/2, mPaint);
                break;
            default:
            }
            
            if(mCnt==5){
                
                if(th.isAlive()){
                    
                    th.interrupt();
                }
                
            }
            
            canvas.drawRect(0, 0, stp, mScreenHeight, mPaint);

        }
    }
    
    Handler myHandler = new Handler() {
        public void handleMessage(Message msg) { 
            switch(msg.what){
            case MSG_UPDATE_START:
                Log.i(TAG,"revice MSG_UPDATE_START msg");
                break;
            case MSG_UPDATE_STOP:
                Log.i(TAG,"revice MSG_UPDATE_STOP msg");
                break;
            case MSG_UPDATE_REGION:
                Log.i(TAG,"revice MSG_UPDATE_REGION msg");
                /**
                 * Invalidate the whole view. If the view is visible, 
                 * onDraw(Canvas) will be called at some point in the future. 
                 * This must be called from a UI thread. To call from a non-UI 
                 * thread, call postInvalidate(). 
                 */
                dv.invalidate(); //实际调用的函数是DrawViewer中的onDraw()函数
                break;
            }
            super.handleMessage(msg);
        }
    };
    
    class myTestThread implements Runnable {
        private void sendMsg(int what) {
            Message message = new Message();
            message.what = what;
            myHandler.sendMessage(message);
        }

        public void run() {
            this.sendMsg(MSG_UPDATE_START);
            while (!Thread.currentThread().isInterrupted()) {
                try {
                    this.sendMsg(MSG_UPDATE_REGION);
                    Thread.sleep(5);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }
            this.sendMsg(MSG_UPDATE_STOP);
        }
    }
    
    
    
    
}