Android之进度条2

package com.cdp.progressbar;
 
import android.app.Activity;
import android.os.Bundle;
import android.widget.ProgressBar;
    //使用Runnable接口
public class MainActivity extends Activity implements Runnable {
    //声明一条线程
    private Thread th ;  
    //声明一个进度条对象 
    private ProgressBar pb ;    
     //标识进度值最大最小的状态
    private boolean stateChage;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main); 
        //实例进度条对象
        pb = (ProgressBar)findViewById(R.id.porb); 
        //实例线程对象
        th = new Thread(this);
        //启动线程
        th.start();
    }
 
    @Override
    public void run() {//实现Runnable接口抽象函数
        while(true){ 
            //得到当前进度值
            int current = pb.getProgress();
            //得到进度条的最大进度值   
            int currentMax = pb.getMax();
            //得到底层当前进度值     
            int secCurrent = pb.getSecondaryProgress();
            //以下代码实现进度值越来越大，越来越小的一个动态效果
            if(stateChage==false){ 
                if(current>=currentMax){ 
                    stateChage=true; 
                }else{
                    //设置进度值
                    pb.setProgress(current+1);
                    //设置底层进度值
                    pb.setSecondaryProgress(current+1);
                }
            }else{
                if(current<=0){ 
                    stateChage=false; 
                }else{
                    pb.setProgress(current-1);
                    pb.setSecondaryProgress(current-1);
                }
            }
            try {
                Thread.sleep(50);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}