android handler msg的使用 实现进度条

package com.app.threadtest;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.view.View;import android.widget.Button;import android.widget.ProgressBar;public class MyActivity extends Activity {//private static final int PROGRESS = 0x1;private ProgressBar mProgress;private Button mButton;private int mProgressStatus = 0;private Handler mHandler = new Handler();protected void onCreate(Bundle icicle) {super.onCreate(icicle);setContentView(R.layout.progressbar_activity);mProgress = (ProgressBar) findViewById(R.id.progress_bar);// 按钮事件mButton = (Button) findViewById(R.id.button1);mButton.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// Start lengthy operation in a background threadnew Thread(new Runnable() {public void run() {while (mProgressStatus < 100) {mProgressStatus = doWork();// Update the progress barmHandler.post(new Runnable() {public void run() {mProgress.setProgress(mProgressStatus);}});}}}).start();}});}protected int doWork() {mProgressStatus++;return mProgressStatus;}}