<?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">
 <EditText android:text="" 
  android:id="@+id/editText"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content" 
  android:editable="false"
  android:cursorVisible="false" />
 <Button android:text="显示普通对话框" 
  android:id="@+id/button"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content" />
</LinearLayout>

package com.ljq.dialog;
import android.app.Activity;
import android.app.Dialog;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class AlertDialog extends Activity {
 private EditText editText;
 private final static int DIALOG=1;
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  editText=(EditText)findViewById(R.id.editText);
  Button button = (Button) findViewById(R.id.button);
  button.setOnClickListener(new View.OnClickListener() {
   public void onClick(View v) {
    // 显示对话框
    showDialog(DIALOG);
   }
  });
 }
 /**
  * 创建普通对话框
  */
 @Override
 protected Dialog onCreateDialog(int id) {
  Dialog dialog=null;
  switch (id) {
  case DIALOG:
   Builder builder=new android.app.AlertDialog.Builder(this);
   //设置对话框的图标
   builder.setIcon(R.drawable.header);
   //设置对话框的标题
   builder.setTitle("普通对话框");
   //设置对话框的显示内容
   builder.setMessage("这是普通对话框中的内容！！");
   //添加按钮，android.content.DialogInterface.OnClickListener.OnClickListener
   builder.setPositiveButton(" 确 定 ", new OnClickListener(){
    public void onClick(DialogInterface dialog, int which) {
     editText.setText("这是普通对话框中的内容！！");
    }
   });
   //创建一个普通对话框
   dialog=builder.create();
   break;
  }
  return dialog;
 }
}