如何在手机通知中添加定时器

Question

我正在尝试在我的应用程序中获取带有计时器的通知。我尝试观看一些指南并从 GPT 获取帮助，但我的服务由于某种原因没有显示我的通知。

这是我的服务，由于某种原因通知不起作用。我做错了什么以及如何解决它？

package com.example.main_app;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.Build;
import android.os.CountDownTimer;
import android.os.IBinder;
import android.util.Log;

import androidx.core.app.NotificationCompat;

public class TimerService extends Service {

    private static final String TAG = "TimerService";
    public static final String TIMER_UPDATED_ACTION = "com.example.main_app.TIMER_UPDATED";
    public static final String TIMER_REMAINING_KEY = "timer_remaining";

    private static final String CHANNEL_ID = "TimerServiceChannel";
    private static final int NOTIFICATION_ID = 1;

    private final IBinder binder = new LocalBinder();
    private CountDownTimer countDownTimer;
    private long timeLeftInMillis;
    private boolean timerRunning = false;

    public class LocalBinder extends Binder {
        TimerService getService() {
            return TimerService.this;
        }
    }

    @Override
    public void onCreate() {
        super.onCreate();
        createNotificationChannel();
    }

    @Override
    public IBinder onBind(Intent intent) {
        Log.d(TAG, "Service onBind");
        return binder;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d(TAG, "Service onStartCommand");
        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (timerRunning) {
            countDownTimer.cancel();
        }
        Log.d(TAG, "Service onDestroy");
    }

    public void startTimer(long durationInMillis) {
        if (timerRunning) {
            return;
        }
        Log.d(TAG, "Timer started for: " + durationInMillis);
        timeLeftInMillis = durationInMillis;
        countDownTimer = new CountDownTimer(timeLeftInMillis, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                timeLeftInMillis = millisUntilFinished;
                Log.d(TAG, "Timer onTick: " + millisUntilFinished);
                sendTimerUpdate();
                updateNotification(millisUntilFinished);
            }

            @Override
            public void onFinish() {
                timerRunning = false;
                Log.d(TAG, "Timer finished");
                sendTimerUpdate();
                updateNotification(0);
                stopSelf(); // Stop the service when the timer finishes
            }
        };
        countDownTimer.start();
        timerRunning = true;
        startForeground(NOTIFICATION_ID, getNotification(timeLeftInMillis));
    }

    public void pauseTimer() {
        if (timerRunning) {
            countDownTimer.cancel();
            timerRunning = false;
            Log.d(TAG, "Timer paused");
            sendTimerUpdate();
            updateNotification(timeLeftInMillis);
        }
    }

    public void stopTimer() {
        if (countDownTimer != null) {
            countDownTimer.cancel();
        }
        timerRunning = false;
        timeLeftInMillis = 0;
        Log.d(TAG, "Timer stopped");
        sendTimerUpdate();
        stopForeground(true);
        stopSelf(); // Stop the service when the timer is manually stopped
    }

    private void sendTimerUpdate() {
        Intent intent = new Intent(TIMER_UPDATED_ACTION);
        intent.putExtra(TIMER_REMAINING_KEY, timeLeftInMillis);
        sendBroadcast(intent);
    }

    private void createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            CharSequence name = "Timer Service Channel";
            String description = "Channel for Timer Service";
            int importance = NotificationManager.IMPORTANCE_DEFAULT;
            NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
            channel.setDescription(description);

            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
    }

    private Notification getNotification(long millisUntilFinished) {
        return new NotificationCompat.Builder(this, CHANNEL_ID)
                .setContentTitle("Timer Running")
                .setContentText("Time remaining: " + millisUntilFinished / 1000 + " seconds")
                .setSmallIcon(R.drawable.ic_timer)
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setOngoing(true)
                .build();
    }

    private void updateNotification(long millisUntilFinished) {
        NotificationManager notificationManager = getSystemService(NotificationManager.class);
        notificationManager.notify(NOTIFICATION_ID, getNotification(millisUntilFinished));
    }
}

Answer 1

从这里开始以及以下所有章节：https://developer.android.com/develop/ui/views/notifications 在您的代码中，我看不到您的目标 Android 版本，这会影响您代码的所有架构。特别是为了获得发布通知的权限（https://developer.android.com/develop/ui/views/notifications/notification-permission） 其次，对于来自后台和前台服务的通知有非常严格的规则（https://developer.android.com/develop/background-work/services）。祝你好运，这是一条漫长而曲折的路