安卓学习笔记【二】AlertDialog(对话框)使用

使用对话框的时候有些点击了并不会自己消失需要自己添加.heid（）来隐藏，这样用户体验会更好。

下面来看看效果：

1.基本使用流程

• Step 1：创建AlertDialog.Builder对象；
• Step 2：调用setIcon()设置图标，setTitle()或setCustomTitle()设置标题；
• Step 3：设置对话框的内容：setMessage()还有其他方法来指定显示的内容；
• Step 4：调用setPositive/Negative/NeutralButton()设置：确定，取消，中立按钮；
• Step 5：调用create()方法创建这个对象，再调用show()方法将对话框显示出来；

附上代码：
MainActivity.java

package nguhyw.alertdialog;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button btn_normal;
    private Button btn_List1;
    private Button btn_List2;
    private Button btn_List3;

    private Context mContext;
    private boolean[] checkItems;

    private AlertDialog alert = null;
    private AlertDialog.Builder builder = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mContext = MainActivity.this;
        binView();
    }

    public void binView(){
        btn_normal = (Button)findViewById(R.id.btn_normal);
        btn_List1 = (Button)findViewById(R.id.btn_List1);
        btn_List2 = (Button)findViewById(R.id.btn_List2);
        btn_List3 = (Button)findViewById(R.id.btn_List3);

        btn_normal.setOnClickListener(this);
        btn_List1.setOnClickListener(this);
        btn_List2.setOnClickListener(this);
        btn_List3.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {

        switch (v.getId()){
            case R.id.btn_normal:
                show_normal_dialog();
                break;

            case R.id.btn_List1:
                show_List1_dialog();
                break;

            case R.id.btn_List2:
                show_List2_dialog();
                break;

            case R.id.btn_List3:
                show_List3_dialog();
                break;

            default:
                break;
        }

    }

    public void show_normal_dialog(){

        alert = null;
        builder = new AlertDialog.Builder(mContext);
        alert = builder.setIcon(R.drawable.nguhyw)
                .setTitle("系统提示")
                .setMessage("这是一个很普通的对话框，你想打我也没用！")
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(mContext,"你点击了取消按钮",Toast.LENGTH_SHORT).show();
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(mContext,"你点击了确定按钮",Toast.LENGTH_SHORT).show();
                    }
                })
                .setNeutralButton("中立", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(mContext, "你点击了中立按钮", Toast.LENGTH_SHORT).show();
                    }
                })
                .create();
        alert.show();
    }

    public void show_List1_dialog(){
        final String[] lesson = new String[]{"语文","数学","英语","物理","化学","生物","历史",};
        alert = null;
        builder = new AlertDialog.Builder(mContext);
        alert = builder.setIcon(R.drawable.nguhyw)
                .setTitle("选择你喜欢的课程")
                .setItems(lesson, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(getApplicationContext(),"你选择了"+lesson[which],Toast.LENGTH_SHORT).show();
                        alert.hide();
                    }
                })
                .create();
        alert.show();
    }

    public void show_List2_dialog(){
        final String[] fruits = new String[]{"苹果", "雪梨", "香蕉", "葡萄", "西瓜"};
        alert = null;
        builder = new AlertDialog.Builder(mContext);
        alert = builder.setIcon(R.drawable.nguhyw)
                .setTitle("选择你喜欢的水果")
                .setSingleChoiceItems(fruits, 0, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(getApplicationContext(),"你选择了"+fruits[which],Toast.LENGTH_SHORT).show();
                        alert.hide();
                    }
                }).create();
        alert.show();
    }

    public void show_List3_dialog(){
        final String[] menu = new String[]{"水煮豆腐", "萝卜牛腩", "酱油鸡", "胡椒猪肚鸡"};
        checkItems = new boolean[]{false, false, false, false};

        alert = null;
        builder = new AlertDialog.Builder(mContext);
        alert = builder.setIcon(R.drawable.nguhyw)
                .setMultiChoiceItems(menu, checkItems, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        checkItems[which] = isChecked;
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        String result = "";
                        for(int i=0; i<checkItems.length;i++){
                            if(checkItems[i])
                                result += menu[i] + " ";
                        }
                        Toast.makeText(getApplicationContext(), "客官你点了:" + result, Toast.LENGTH_SHORT).show();
                    }
                }).create();
        alert.show();
    }
}

XML文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
    xmlns:tools="" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1、显示一个普通的对话框"
            android:id="@+id/btn_normal" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2、显示一个列表对话框"
            android:id="@+id/btn_List1" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3、显示一个单选的列表"
            android:id="@+id/btn_List2" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3、显示一个复选框的列表"
            android:id="@+id/btn_List3" />
    </LinearLayout>
</RelativeLayout>

本次介绍的对话框用法非常简单~无非就是创建一个Builder对象后， 进行相关设置，然后create()生成一个AlertDialog对象，最后调用show()方法将AlertDialog 显示出来而已！另外，细心的你可能发现我们点击对话框的外部区域，对话框就会消失，我们 可以为builder设置setCancelable(false)即可解决这个问题！