如何制作Android显示百分比数字的状态条。

main.xml

<?xml version="1.0" encoding="utf-8"?>
<!--  -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="30dip"
android:padding="0dip"
>
<ProgressBar android:id="@+id/progress"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="fill_parent"
android:indeterminateOnly="false"
android:layout_height="30dip"  />
<TextView
android:id="@+id/perc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textColor="#ff0000"
android:textStyle="bold"
/>
</RelativeLayout>

代码：
package wxk.com;

import android.app.Activity;
import android.os.Bundle;
import android.os.Message;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
public class ThreadDemoActivity extends Activity {
    ProgressBar bar;
    TextView percent;
    Handler handler=new Handler() {
    @Override
    public void handleMessage(Message msg) {
    bar.incrementProgressBy(5);
    percent.setText(String.format("%03d%%", bar.getProgress()));
    }
    };
    boolean isRunning=false;
    @Override
    public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);
    bar=(ProgressBar)findViewById(R.id.progress);
    percent=(TextView)findViewById(R.id.perc);
    }
    public void onStart() {
    super.onStart();
    bar.setProgress(0);

    Thread background=new Thread(new Runnable() {
    public void run() {
    try {
    for (int i=0;i<20 && isRunning;i++) {
    Thread.sleep(1000);
    handler.sendMessage(handler.obtainMessage());
    }
    }
    catch (Throwable t) {
    // just end the background thread
    }
    }
    });
    isRunning=true;
    background.start();
    }
    public void onStop() {
    super.onStop();
    isRunning=false;
    }
}