android学习笔记12(ProgressBar--进度条--初级学习)

package tk.progressbar;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;

public class MyProgressBar extends Activity {

private ProgressBar firstBar=null;
private ProgressBar secondbBar=null;
private Button myButton=null;
private int i=0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.progress_bar);
firstBar  =  (ProgressBar)findViewById(R.id.firstBar);
secondbBar = (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){

firstBar.setVisibility(View.VISIBLE);
secondbBar.setVisibility(View.VISIBLE);
firstBar.setProgress(i);
firstBar.setSecondaryProgress(i);
}else if(i<firstBar.getMax()){
firstBar.setProgress(i);
firstBar.setSecondaryProgress(i 10);
secondbBar.setProgress(i);
}else{
firstBar.setVisibility(View.GONE);
secondbBar.setVisibility(View.GONE);
i=-10;
}
i =10;
}

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.progress_bar, menu);
return true;
}
}

<?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:id="@ id/textView1"
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"
android:max="200"
/>
<ProgressBar
android:id="@ id/secondBar"
style="?android:attr/progressBarStyle"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:visibility="gone"
/>
<Button
android:id="@ id/myButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="begin"
/>

</LinearLayout>