Android入门之AlertDialog用法实例分析

本文实例讲述的是AlertDialog，这种对话框会经常遇到。AlertDialog跟WIN32开发中的Dialog不一样，AlertDialog是非阻塞的，而阻塞的对话框用的是PopupWindow。

先贴出该程序运行的截图：

main.xml的源码：

<?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"
 >

<Button android:id="@+id/Button01" android:layout_height="wrap_content" android:text="非Layout型对话框" android:layout_width="fill_parent"></Button>
<Button android:id="@+id/Button02" android:layout_height="wrap_content" android:text="Layout型对话框" android:layout_width="fill_parent"></Button><View android:id="@+id/View01" android:layout_width="wrap_content" android:layout_height="wrap_content"></View>

</LinearLayout>

下图是非Layout型对话框，直接使用AlertDialog

下图是使用了Layout的对话框，可以自定义控件，实现更复杂的对话框

dialoglayout.xml的源码：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:orientation="vertical">
<EditText android:layout_height="wrap_content"
android:layout_width="fill_parent" android:layout_marginLeft="20dip"
android:layout_marginRight="20dip" android:textAppearance="?android:attr/textAppearanceMedium" android:id="@+id/edtInput"/>
</LinearLayout>

程序源码：

package com.testAlertDialog;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.PopupWindow;

public class testAlertDialog extends Activity {
Button btnShowDialog;
Button btnShowDialog_Layout;
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.main);
   //定义按钮
   btnShowDialog=(Button)this.findViewById(R.id.Button01);
   btnShowDialog.setOnClickListener(new ClickEvent());
   btnShowDialog_Layout=(Button)this.findViewById(R.id.Button02);
   btnShowDialog_Layout.setOnClickListener(new ClickEvent());
 }

//统一处理按键事件
 class ClickEvent implements OnClickListener{

@Override
  public void onClick(View v) {
  // TODO Auto-generated method stub
  if(v==btnShowDialog)
   showDialog(testAlertDialog.this);

else if(v==btnShowDialog_Layout)
   showDialog_Layout(testAlertDialog.this);

}

}

//显示基本的AlertDialog
private void showDialog(Context context) {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setIcon(R.drawable.icon);
builder.setTitle("Title");
builder.setMessage("Message");
builder.setPositiveButton("Button1",
 new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
  setTitle("点击了对话框上的Button1");
  }
 });
builder.setNeutralButton("Button2",
 new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
  setTitle("点击了对话框上的Button2");
  }
 });
builder.setNegativeButton("Button3",
 new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
  setTitle("点击了对话框上的Button3");
  }
 });
builder.show();
}

//显示基于Layout的AlertDialog
private void showDialog_Layout(Context context) {
LayoutInflater inflater = LayoutInflater.from(this);
final View textEntryView = inflater.inflate(
 R.layout.dialoglayout, null);
final EditText edtInput=(EditText)textEntryView.findViewById(R.id.edtInput);
final AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setCancelable(false);
builder.setIcon(R.drawable.icon);
builder.setTitle("Title");
builder.setView(textEntryView);
builder.setPositiveButton("确认",
 new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
  setTitle(edtInput.getText());
  }
 });
builder.setNegativeButton("取消",
 new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
  setTitle("");
  }
 });
builder.show();
}
}