什么是Dialog？
Dialog类，是一切对话框的基类，需要注意的是，Dialog类虽然可以在界面上显示，但是并非继承于View类，而是直接从java.lang.Object开始构造出的。类似于Activity，Dialog也是有生命周期的，它的生命周期由Activity来维护。Activity负责生成、保存、恢复它。在生命周期的每一个阶段都有一些回调函数供系统反向调用。
什么是AlertDialog?什么是AlertDialog.Builder?
AlertDialog是Dialog的一个直接子类，一个AlertDialog可以有两个Button或者3个Button，可以对一个AlertDialog设置title、message。不能直接通过AlertDialog的构造函数来生成一个AlertDialog，一般生成的时候都是通过它的的一个内部静态类AlertDialog.Builder来构造的。
下列是实例图：
MainActivity.java
package com.shaoxin.myapplication; import android.app.Activity;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.util.Log;
import android.view.View;
import android.widget.Button; import java.util.ArrayList;
import java.util.List; public class MainActivity extends Activity {
private Button btn1;
private Button btn2;
private Button btn3;
private Button btn4;
private Button btn5; private MyBtnClick btnClick;
private Dialog dialog;
private String[] strCitys = {"南昌", "上海", "北京"};
private int cityIndex = 0;
private List data; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
setListener();
} private void setListener() {
btnClick = new MyBtnClick();
data = new ArrayList();
btn1.setOnClickListener(btnClick);
btn2.setOnClickListener(btnClick);
btn3.setOnClickListener(btnClick);
btn4.setOnClickListener(btnClick);
btn5.setOnClickListener(btnClick);
} private void init() {
btn1 = (Button) findViewById(R.id.btn_1);
btn2 = (Button) findViewById(R.id.btn_2);
btn3 = (Button) findViewById(R.id.btn_3);
btn4 = (Button) findViewById(R.id.btn_4);
btn5 = (Button) findViewById(R.id.btn_5);
} private class MyBtnClick implements View.OnClickListener {
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_5: {
final AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
dialogBuilder.setTitle("单选对话框");
dialogBuilder.setIcon(R.mipmap.ic_launcher);
View view_1 = View.inflate(MainActivity.this, R.layout.dialog_item, null);
dialogBuilder.setView(view_1);
dialogBuilder.setNeutralButton("确定", null);
dialogBuilder.create().show();
}
break;
case R.id.btn_4: {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
dialogBuilder.setTitle("多选对话框");
dialogBuilder.setIcon(R.mipmap.ic_launcher);
data.clear();
dialogBuilder.setMultiChoiceItems(R.array.citys, new boolean[]{false, false, false},
new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialog, int which, boolean isChecked) {
String[] citys = getResources().getStringArray(R.array.citys); if (isChecked) {
data.add(citys[which]);
} else {
data.remove(citys[which]);
}
}
});
dialogBuilder.setNeutralButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.v("msg", data.toString());
}
});
dialogBuilder.create().show();
}
break;
case R.id.btn_3: {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
dialogBuilder.setTitle("单选对话框");
dialogBuilder.setIcon(R.mipmap.ic_launcher);
dialogBuilder.setSingleChoiceItems(R.array.citys, 0, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//获取内容
cityIndex = which; }
});
dialogBuilder.setNeutralButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String[] citys = getResources().getStringArray(R.array.citys);
Log.v("msg", citys[cityIndex]);
}
});
dialogBuilder.create().show();
}
break;
case R.id.btn_2: {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
dialogBuilder.setTitle("简单ITEM对话框");
dialogBuilder.setIcon(R.mipmap.ic_launcher);
dialogBuilder.setItems(strCitys, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.v("msg", strCitys[which]);
}
});
dialogBuilder.create().show();
}
break;
case R.id.btn_1: {
Log.v("msg", "sdf");
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
dialogBuilder.setTitle("简单对话框");
dialogBuilder.setIcon(R.mipmap.ic_launcher);
dialogBuilder.setMessage("是否退出对话框?");
dialogBuilder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
finish();
}
});
dialogBuilder.setNegativeButton("取消", null);
dialogBuilder.setNeutralButton("更多", null);
dialogBuilder.create().show();
} break;
}
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.shaoxin.myapplication.MainActivity"> <Button
android:id="@+id/btn_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="简单对话框" /> <Button
android:id="@+id/btn_2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="简单item对话框" /> <Button
android:id="@+id/btn_3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="单选对话框" /> <Button
android:id="@+id/btn_4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="多选对话框" /> <Button
android:id="@+id/btn_5"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="自定义对话框" />
</LinearLayout>
dialog_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"> <ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:src="@mipmap/ic_launcher" />
</LinearLayout>
arrays.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="citys">
<item>南昌</item>
<item>北京</item>
<item>上海</item>
</string-array>
</resources>
将代码导入直接运行即可