Android 中带有进度条效果的按钮（Button）

安卓中带有进度条效果的按钮，如下图：

1.布局文件如下activity_main.xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
     tools:context=".MainActivity" >

     <TextView
         android:id="@+id/text"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="带有进度条的Button" />

     <RelativeLayout
         android:layout_width="fill_parent"
         android:layout_height="50dp"
         android:layout_centerHorizontal="true"
         android:layout_centerVertical="true"
         android:gravity="bottom" >

         <ProgressBar
             android:id="@+id/progressBar"
             style="?android:attr/progressBarStyleHorizontal"
             android:layout_width="fill_parent"
             android:layout_height="fill_parent"
             android:background="@drawable/aa_button_gray_normal"
             android:max="100"
             android:progress="0"
             android:progressDrawable="@drawable/progress_selector" />

         <Button
             android:id="@+id/downLoadBtn"
             android:layout_width="fill_parent"
             android:layout_height="fill_parent"
             android:layout_centerHorizontal="true"
             android:layout_centerVertical="true"
             android:background="@drawable/btn_selector"
             android:text="下载" />
     </RelativeLayout>

 </RelativeLayout>

2.java主界面代码如下：MainActivity.java

 package com.example.buttondemo;

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.view.View;
 import android.widget.Button;
 import android.widget.ProgressBar;
 import android.widget.TextView;

 public class MainActivity extends Activity {
     int i = 0;
     ProgressBar progressBar = null;
     Button downLoadBtn = null;
     Handler handler = new Handler() {
         public void handleMessage(android.os.Message msg) {
             switch (msg.what) {
             case 1:
                 i += 5;
                 progressBar.setProgress(i);
                 if (i != 100) {
                     handler.sendEmptyMessageDelayed(new Message().what = 1, 500);
                     downLoadBtn.setText(i + "%");
                 } else if (i == 100) {
                     downLoadBtn.setText("下载完成");
                     // 进度条运行完成时按钮可用
                     downLoadBtn.setEnabled(true);
                 }
                 break;

             default:
                 break;
             }
         };
     };

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         TextView tx = (TextView) findViewById(R.id.text);
         progressBar = (ProgressBar) findViewById(R.id.progressBar);
         downLoadBtn = (Button) findViewById(R.id.downLoadBtn);
         downLoadBtn.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View v) {
                 i = 0;
                 handler.sendEmptyMessage(new Message().what = 1);
                 // 进度条运行时按钮不可用
                 downLoadBtn.setEnabled(false);
             }
         });
     }

 }