Android创建Alert框的方法

package com.akwolf.android;
import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class DialogActivity extends Activity {
 /** Called when the activity is first created. */
 Button dialogBtn;
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  dialogBtn = (Button) findViewById(R.id.button1);
  dialogBtn.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
    new AlertDialog.Builder(DialogActivity.this)
      .setIcon(R.drawable.icon).setTitle("Infomation")
      .setMessage("Hello World").show();
   }
  });
 }
}