demo15 AlertDialog

       Dialog dialog = new AlertDialog.Builder(this).setTitle("对话框").setMessage("this is msg info").setIcon(R.drawable.ic_launcher).create();
        dialog.show();

package com.example.demo15alertdialog;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {
private Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        this.button=(Button)super.findViewById(R.id._btn);

        this.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Dialog dialog = new AlertDialog.Builder(MainActivity.this).setTitle("对话框")
                        .setMessage("this is msg info")
                        .setIcon(R.drawable.ic_launcher)
                        .setPositiveButton("Delete",new DialogInterface.OnClickListener(){public void onClick(DialogInterface dialogInterface,int whichButton) {
                        }})
                        .setNeutralButton("Show Detail",new DialogInterface.OnClickListener(){public void onClick(DialogInterface dialogInterface,int whichButton) {
                        }})
                        .setNegativeButton("Cancel",new DialogInterface.OnClickListener(){public void onClick(DialogInterface dialogInterface,int whichButton) {
                        }})
                        .create();
                dialog.show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}