Android实现带有进度条的按钮效果

<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>

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);
       }
     });
   }
 
}