9.AlertDialog对话框的实现

一、AlertDialog的实现方式

1.AlertDialog.Builder builder=new AlertDialog.Builder(context); 构建Dialog的各种参数<br />    2.Builder.setIcon(int iconId); 添加ICON<br />    3.Builder.setTitle(CharSequence title); 添加标题<br />    4.Builder.setMessage(CharSequence message); 添加信息<br />    5.Builder.setView(View view); 设置自定义布局<br />    6.Builder.create(); 创建Dialog<br />    7.Builder.show(); 显示对话框<br />    8.setPositiveButton 确定按钮<br />    9.setNegativeButton 取消按钮<br />    10.setNeutralButton 中间按钮

二、对话框的实现

1.布局activity_main.xml代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="显示对话框"
        android:onClick="dialog"
        />
</LinearLayout>

2.自定义对话框布局dialog_view.xml代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="horizontal"
    android:background="#9344A8">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="哈哈，今天天气真好"
        android:textSize="30dp"
        />
</LinearLayout>

3.MainActivity文件代码

package com.example.myalertdialog;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
  //1.创建按钮点击出现的对话框方法
    public void dialog(View view) {
        //5.创建自定义对话框布局
        View view1 = getLayoutInflater().inflate(R.layout.dialog_view, null);
        //2.创建对话框的构建器
        AlertDialog.Builder builder=new AlertDialog.Builder(this);
        builder.setIcon(R.mipmap.ic_launcher)
                .setTitle("我是对话框")
                .setMessage("今天天气怎么样啊")
                //4.创建自定义布局
                .setView(view1)
                //3.创建对话框的确定按钮、取消按钮和中间按钮
                .setPositiveButton("确定按钮", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                     Toast.makeText(MainActivity.this, "确定按钮", Toast.LENGTH_SHORT).show();
                    }
                })
                .setNegativeButton("取消按钮", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                    Toast.makeText(MainActivity.this, "取消按钮", Toast.LENGTH_SHORT).show();
                    }
                })
                .setNeutralButton("中间按钮", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                    Toast.makeText(MainActivity.this, "中间按钮", Toast.LENGTH_SHORT).show();
                    }
                })
                .create()
                .show();
    }
}

4.效果图：<br />![image.png](https://cdn.nlark.com/yuque/0/2021/png/1574587/1621954886980-ef60068c-4582-4210-80ba-9d2213da0138.png#clientId=u91c9e385-00c5-4&from=paste&height=409&id=ucc9ae46e&margin=%5Bobject%20Object%5D&name=image.png&originHeight=409&originWidth=866&originalType=binary&size=89127&status=done&style=none&taskId=u0030d5d7-53a0-45f1-8350-d85b816531f&width=866)