1、當前界面彈出的一個小窗口，用於提示用戶重要的信息，並獲得焦點。
2、用戶要與它進行互動，可以接受用戶輸入的信息，也可以反饋信息給用戶，如下載進度，退出提示等。常用的對話框：
1、簡單對話框
2、簡單列表對話框3、單選按鈕對話框
4、多選按鈕對話框5、自定義列表對話框
6、自定義佈局對話框
對話框包含四個區域：
1、圖標區
2、標題區3、內容區
4、按鈕區如何創建對話框：
1、創建AlertDialog.Builder的對象
2、使用Builder的setTitle()或者setCustomTitil()來設置標題。
3、使用Builder的setIcon()來設置圖標4、使用Builder的相關方法來設置內容
5、使用Builder的setpositivebutton()和setnegativeButton()設置按鈕，setNeutralButton()用於設置中立的按鈕。6、使用Builder的create()方法創建一個AlertDialog的對象。
7、然後把Dialog對象通過show()方法顯示出來。AlertDialog.Builder提供了六種指定對話框內容的方法
1、setMessage() 設置對話框內容爲簡單的文本格式。
2、setitems() 設置對話框的內容爲簡單的列表項。3、setSingleChoiceItems 設置對話框的內容爲單選按鈕的列表項
4、setMultiChoiceitems() 設置對話框內容爲多選按鈕列表項
5、setAdapter() 設置對話框內容爲自定義的列表項6、setView() 設置對話框內容爲自定義的View
package com.example.toast_demo01;
import java.util.ArrayList;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;
@SuppressLint("ShowToast")
public class AlertDialogDemo extends Activity implements OnClickListener {
private Button button1;
private Button button2;
private Button button3;
private Button button4;
private Button button5;
private Button button6;
private Button button7;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.alertaialog);
initEvent();
}
// findViewById集合方法
public void initEvent() {
button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(this);
button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(this);
button3 = (Button) findViewById(R.id.button3);
button3.setOnClickListener(this);
button4 = (Button) findViewById(R.id.button4);
button4.setOnClickListener(this);
button5 = (Button) findViewById(R.id.button5);
button5.setOnClickListener(this);
button6 = (Button) findViewById(R.id.button6);
button6.setOnClickListener(this);
button7 = (Button) findViewById(R.id.button7);
button7.setOnClickListener(this);
}
// 監聽事件
public void onClick(View v) {
switch (v.getId()) {
case R.id.button1:
simpleDialog();
break;
case R.id.button2:
simpleListDialog();
break;
case R.id.button3:
simpleSingleChoiceDialog();
break;
case R.id.button4:
simpleMultiChoiceDialog();
break;
case R.id.button5:
simpleCustomAdapterDiaglog();
break;
case R.id.button6:
simpleCustomViewDialog();
break;
default:
break;
}
}
// 簡單窗口
public void simpleDialog() {
// AlertDialog.Builder不寫出全局：如果全局，會被反覆賦值，這樣容易產生錯誤。
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("對話框提示信息");
builder.setMessage("簡單的對話框");
// 設置第一個按鈕
builder.setPositiveButton("確認", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, "確認", 0).show();
}
});
// 設置中間按鈕
builder.setNeutralButton("中立", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, "中立", 0).show();
}
});
// 設置最後一個按鈕
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, "取消", 0).show();
}
});
// 顯示對話框關鍵性代碼,沒寫的話對話框不顯示
builder.create().show();
}
// 選項數組
String items[] = { "三國", "水滸", "紅樓", "西遊" };
// 簡單列表窗口
public void simpleListDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("列表對話框");
// 對話框中內容爲列表的寫法
builder.setItems(items, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, items[which], 0).show();
}
});
builder.create().show();
}
// 單選按鈕對話框
int singleIndex = 0;
public void simpleSingleChoiceDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("單選按鈕對話框");
builder.setSingleChoiceItems(items, 0,
new DialogInterface.OnClickListener() {
// 0爲默認選擇的按鈕
@Override
public void onClick(DialogInterface dialog, int which) {
singleIndex = which;
}
});
builder.setPositiveButton("確認", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, items[singleIndex], 0)
.show();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
builder.create().show();
}
// 定義多選選項的初始狀態
boolean checkedItems[] = { false, false, false, false };
ArrayList<Integer> myChseList = new ArrayList<Integer>();
// 多選按鈕對話框
public void simpleMultiChoiceDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("多選按鈕對話框");
builder.setMultiChoiceItems(items, checkedItems,
new DialogInterface.OnMultiChoiceClickListener() {
public void onClick(DialogInterface dialog, int which,
boolean isChecked) {
// 改變選中項的狀態
checkedItems[which] = isChecked;
if (isChecked) {
myChseList.add(which);
} else {
myChseList.remove(which);
}
}
});
builder.setPositiveButton("確認", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
String multi = "";
// Toast各個選中項
for (int i = 0; i < checkedItems.length; i++) {
if (checkedItems[i] == true) {
multi = multi + items[i];
checkedItems[i] = false;
}
}
Toast.makeText(AlertDialogDemo.this, multi, 0).show();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
builder.create().show();
}
// 自定義列表對話框
public void simpleCustomAdapterDiaglog() {
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("自定義對話框");
builder.setAdapter(new ArrayAdapter<String>(AlertDialogDemo.this,
android.R.layout.simple_list_item_1, items),
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(AlertDialogDemo.this, items[which], 0)
.show();
}
});
builder.create().show();
}
// 自定義佈局對話框
@SuppressWarnings("unused")
private void simpleCustomViewDialog() {
LinearLayout layout = (LinearLayout) getLayoutInflater().inflate(
R.layout.dialog_login, null);
AlertDialog.Builder builder = new AlertDialog.Builder(
AlertDialogDemo.this);
builder.setIcon(R.drawable.ic_launcher);
builder.setTitle("自定義佈局對話框");
builder.setView(layout);
builder.setPositiveButton("確認", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
builder.create().show();
}
}