android notification （通知的实现）

private NotificationManager manager;
private Notification notification;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.base) {
        //对版本进行判断
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            //id在notification中会用到，name可以随意设置，最后一个为优先级
            NotificationChannel channel = new NotificationChannel("myfirst", "ceshi", NotificationManager.importANCE_HIGH);
            manager.createNotificationChannel(channel);
        }

    }

    Intent intent= new Intent(this,目标activity)；
            //将创建的intent转化为pendingintent
            PendingIntent pendingIntent= PendingIntent.getActivity(this,0,intent,0);


    notification = new NotificationCompat.Builder(this, "myfirst")
            .setContentTitle("1")
            .setContentText("wolaile")
            .setSmallIcon(R.drawable.ic_launcher_foreground)
            .setContentIntent(pendingIntent)
            .build();
}

//通知发出函数
public void send(View view){
manager.notify(1,notification);
}
//通知取消函数
public void cancel(View view){manager.cancel(1);}