progressBar的使用

<?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 mars.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);
                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 ;
        }
        
    }
    
}