Android实战教程第二篇之简单实现两种进度条效果

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:orientation="vertical" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 > 
<TextView 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:text="@string/hello" 
 /> 
<ProgressBar 
 android:id="@+id/firstBar" 
 style="?android:attr/progressBarStyleHorizontal" 
 android:layout_width="200dp" 
 android:layout_height="wrap_content" 
 android:visibility="gone" 
 /> 
<ProgressBar 
 android:id="@+id/secondBar" 
 style="?android:attr/progressBarStyle" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:visibility="gone" 
 /> 
<Button 
 android:id="@+id/myButton" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:text="begin" 
 /> 
</LinearLayout> 

package ydl.progressbar; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.ProgressBar; 
 
public class ProgressBarTest extends Activity { 
 /** Called when the activity is first created. */ 
 //声明变量 
 private ProgressBar firstBar =null; 
 private ProgressBar secondBar = null; 
 private Button myButton = null; 
 private int i = 0 ; 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.main); 
  //根据控件的ID来取得代表控件的对象 
  firstBar = (ProgressBar)findViewById(R.id.firstBar); 
  secondBar = (ProgressBar)findViewById(R.id.secondBar); 
  myButton = (Button)findViewById(R.id.myButton); 
  myButton.setOnClickListener(new ButtonListener()); 
 } 
 class ButtonListener implements OnClickListener{ 
   
  @Override 
  public void onClick(View v) { 
   if(i == 0) 
   { 
    //设置进度条处于可见的状态 
    firstBar.setVisibility(View.VISIBLE); 
    firstBar.setMax(150);//手动设置最大值，默认是100 
    secondBar.setVisibility(View.VISIBLE); 
   } 
   else if ( i < firstBar.getMax()){ 
    //设置主进度条的当前值 
    firstBar.setProgress(i); 
    //设置第二进度条的当前值 
    firstBar.setSecondaryProgress(i + 10); 
    //因为默认的进度条无法显示进行的状态 
    //secondBar.setProgress(i); 
     
   } 
   else{ 
    //设置进度条处于不可见状态 
    firstBar.setVisibility(View.GONE); 
    secondBar.setVisibility(View.GONE); 
   } 
   i = i + 10 ; 
  } 
   
 } 
  
}