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