AlertDialog的構造方法全部是Protected的，所以不能直接通過new一個AlertDialog來創建出一個AlertDialog。
要創建一個AlertDialog，就要用到AlertDialog.Builder中的create()方法。
使用AlertDialog.Builder創建對話框需要了解以下幾個方法：
setTitle ：為對話框設置標題
setIcon ：為對話框設置圖標
setMessage：為對話框設置內容
setView ：給對話框設置自定義樣式
setItems ：設置對話框要顯示的一個list，一般用於顯示幾個命令時
setMultiChoiceItems ：用來設置對話框顯示一系列的複選框
setNeutralButton ：普通按鈕
setPositiveButton ：給對話框添加”Yes”按鈕
setNegativeButton ：對話框添加”No”按鈕
create ：創建對話框
show ：顯示對話框
一、簡單的AlertDialog
下面，創建一個簡單的ALertDialog並顯示它：
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . os . Bundle ;
public class Dialog_AlertDialogDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "對話框的標題" ).
setMessage ( "對話框的內容" ).
setIcon ( R . drawable . ic_launcher ).
create ();
alertDialog . show ();
}
}
運行結果如下：
二、帶按鈕的AlertDialog
上面的例子很簡單，下面我們在這個AlertDialog上面加幾個Button，實現刪除操作的提示對話框
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . content . DialogInterface ;
import android . os . Bundle ;
public class Dialog_AlertDialogDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "確定刪除？" ).
setMessage ( "您確定刪除該條信息嗎？" ).
setIcon ( R . drawable . ic_launcher ).
setPositiveButton ( "確定" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
setNegativeButton ( "取消" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
setNeutralButton ( "查看詳情" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
create ();
alertDialog . show ();
}
}
在這個例子中，我們定義了三個按鈕，分別是”Yes”按鈕，”No”按鈕以及一個普通按鈕，每個按鈕都有onClick事件，TODO的地方可以放點了按鈕之後想要做的一些處理
看一下運行結果：
可以看到三個按鈕添加到了AlertDialog上，三個沒有添加事件處理的按鈕，點了只是關閉對話框，沒有任何其他操作。
三、類似ListView的AlertDialog
用setItems(CharSequence[] items, final OnClickListener listener)方法來實現類似ListView的AlertDialog
第一個參數是要顯示的數據的數組，第二個參數是點擊某個item的觸發事件
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . content . DialogInterface ;
import android . os . Bundle ;
import android . widget . Toast ;
public class Dialog_AlertDialogDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
final String [] arrayFruit = new String [] { "蘋果" , "橘子" , "草莓" , "香蕉" };
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "你喜 歡吃哪種水果？" ).
setIcon ( R . drawable . ic_launcher )
. setItems ( arrayFruit , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
Toast . makeText ( Dialog_AlertDialogDemoActivity . this , arrayFruit [ which ], Toast . LENGTH_SHORT ). show ();
}
}).
setNegativeButton ( "取消" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
create ();
alertDialog . show ();
}
}
運行結果如下：
四、類似RadioButton的AlertDialog
用setSingleChoiceItems(CharSequence[] items, int checkedItem, final OnClickListener listener)方法來實現類似RadioButton的AlertDialog
第一個參數是要顯示的數據的數組，第二個參數是初始值（初始被選中的item），第三個參數是點擊某個item的觸發事件
在這個例子裡 面我們設了一個selectedFruitIndex用來記住選中的item的index
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . content . DialogInterface ;
import android . os . Bundle ;
import android . widget . Toast ;
public class Dialog_AlertDialogDemoActivity extends Activity {
private int selectedFruitIndex = 0 ;
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
final String [] arrayFruit = new String [] { "蘋果" , "橘子" , "草莓" , "香蕉" };
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "你喜 歡吃哪種水果？" ).
setIcon ( R . drawable . ic_launcher )
. setSingleChoiceItems ( arrayFruit , 0 , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
selectedFruitIndex = which ;
}
}).
setPositiveButton ( "確認" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
Toast . makeText ( Dialog_AlertDialogDemoActivity . this , arrayFruit [ selectedFruitIndex ], Toast . LENGTH_SHORT ). show ();
}
}).
setNegativeButton ( "取消" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
create ();
alertDialog . show ();
}
}
運行結果如下：
五、類似CheckBox的AlertDialog
用setMultiChoiceItems(CharSequence[] items, boolean[] checkedItems, final OnMultiChoiceClickListener listener)方法來實現類似CheckBox的AlertDialog
第一個參數是要顯示的數據的數組，第二個參數是選中狀態的數組，第三個參數是點擊某個item的觸發事件
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . content . DialogInterface ;
import android . os . Bundle ;
import android . widget . Toast ;
public class Dialog_AlertDialogDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
final String [] arrayFruit = new String [] { "蘋果" , "橘子" , "草莓" , "香蕉" };
final boolean [] arrayFruitSelected = new boolean [] { true , true , false , false };
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "你喜 歡吃哪種水果？" ).
setIcon ( R . drawable . ic_launcher )
. setMultiChoiceItems ( arrayFruit , arrayFruitSelected , new DialogInterface . OnMultiChoiceClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which , boolean isChecked ) {
arrayFruitSelected [ which ] = isChecked ;
}
}).
setPositiveButton ( "確認" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
StringBuilder stringBuilder = new StringBuilder ();
for ( int i = 0 ; i < arrayFruitSelected . length ; i ++) {
if ( arrayFruitSelected [ i ] == true )
{
stringBuilder . append ( arrayFruit [ i ] + "、" );
}
}
Toast . makeText ( Dialog_AlertDialogDemoActivity . this , stringBuilder . toString (), Toast . LENGTH_SHORT ). show ();
}
}).
setNegativeButton ( "取消" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
create ();
alertDialog . show ();
}
}
運行結果如下：
六、自定義View的AlertDialog
有時候我們不能滿足系統自帶的AlertDialog風格，就比如說我們要實現一個Login畫面，有用戶名和密碼，這時我們就要用到自定義View的AlertDialog
先創建Login畫面的佈局文件
<? 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 = "fill_parent"
android:orientation = "vertical" >
<LinearLayout
android:layout_width = "fill_parent"
android:layout_height = "wrap_content"
android:gravity = "center" >
<TextView
android:layout_width = "0dip"
android:layout_height = "wrap_content"
android:layout_weight = "1"
android:text = "@string/user" />
<EditText
android:layout_width = "0dip"
android:layout_height = "wrap_content"
android:layout_weight = "1" />
</LinearLayout>
<LinearLayout
android:layout_width = "fill_parent"
android:layout_height = "wrap_content"
android:gravity = "center" >
<TextView
android:layout_width = "0dip"
android:layout_height = "wrap_content"
android:layout_weight = "1"
android:text = "@string/passward" />
<EditText
android:layout_width = "0dip"
android:layout_height = "wrap_content"
android:layout_weight = "1" />
</LinearLayout>
</LinearLayout>
然後在Activity裡面把Login畫面的佈局文件添加到AlertDialog上
package com . tianjf ;
import android . app . Activity ;
import android . app . AlertDialog ;
import android . app . Dialog ;
import android . content . DialogInterface ;
import android . os . Bundle ;
import android . view . LayoutInflater ;
import android . view . View ;
public class Dialog_AlertDialogDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ) {
super . onCreate ( savedInstanceState );
setContentView ( R . layout . main );
// 取得自定義View
LayoutInflater layoutInflater = LayoutInflater . from ( this );
View myLoginView = layoutInflater . inflate ( R . layout . login , null );
Dialog alertDialog = new AlertDialog . Builder ( this ).
setTitle ( "用戶登錄" ).
setIcon ( R . drawable . ic_launcher ).
setView ( myLoginView ).
setPositiveButton ( "登錄" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
setNegativeButton ( "取消" , new DialogInterface . OnClickListener () {
@Override
public void onClick ( DialogInterface dialog , int which ) {
// TODO Auto-generated method stub
}
}).
create ();
alertDialog . show ();
}
}
運行結果如下：
