package com.example.sixnotification;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.NotificationCompat;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    NotificationManager manager;
    Notification notification;
    private String channelId = "musichhhh";

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

        //获得通知管理器这个对象
        manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        //Android8.0以上的适配
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            //创建通知渠道 这三个参数是必须的  现在我们设置这个通知级别是高的
            NotificationChannel channel = new NotificationChannel(channelId,"音乐消息",NotificationManager.IMPORTANCE_HIGH);
            //创建通知渠道的通知管理器
            NotificationManager manager1 = getSystemService(NotificationManager.class);
            //将通知渠道交给管理器
            manager1.createNotificationChannel(channel);

        }

        //为了setContentIntent这个功能做的activity
        //PendingIntent是对Intent的封装，但它不是立刻执行某个行为，而是满足某些条件或触发某些事件后才执行指定的行为
        Intent intent = new Intent(this, MessageActivity.class);
        PendingIntent activity = PendingIntent.getActivity(this, 250, intent, 0);

        //通知管理
     notification = new NotificationCompat.Builder(this,channelId)
                .setContentTitle("官方通知")
                .setContentText("你的绿钻已到期")
                .setSmallIcon(R.drawable.ic_audiotrack_black_24dp)
                .setContentIntent(activity)
                .build();

    }

    public void sentMessage(View view) {
        manager.notify(250,notification);
    }

    public void cancelSentButton(View view) {
        manager.cancel(250);  //注意昂，这个id要和sentMessage的id一致
    }
}

<?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:id="@+id/sentButton"
        android:text="发送通知"
        android:onClick="sentMessage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/cancelSentButton"
        android:text="取消发送"
        android:onClick="cancelSentButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>