Android 中自定义通知的确切时间

Question

我正在开发 Android 咨询服务应用程序。客户可以在应用程序中查看他们的预定约会。例如，

下一次约会： 2016 年 12 月 31 日 10:00AM

现在我需要做的是让用户收到 2 条通知——约会提醒。一个在 7 天前，另一个在 3 天前。我将这个日期（2016 年 12 月 31 日 10:00AM）保存为 String，这样我就可以提取年、月等。我发现我需要编写某种服务来发送这些通知。这是我试过的（未完成）：

public class NotificationService extends Service {
    @Override
    public void onCreate() {
        Intent resultIntent=new Intent(this, MainActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, resultIntent, 0);
        Notification nBuilder = new Notification.Builder(this)
                .setContentTitle("Don't miss! ")
                .setTicker("Notification!")
                .setContentIntent(pIntent)
                .setDefaults(Notification.DEFAULT_SOUND)
                .setAutoCancel(true)
                .setSmallIcon(R.drawable.my_logo)
                .setContentText("7 days left till your appointment...")
                //.setWhen(System.currentTimeMillis())
                .build();
        NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        nBuilder.flags |=Notification.FLAG_AUTO_CANCEL;
        notificationManager.notify(1,nBuilder);
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

以及我不知道从哪里调用的方法：

public void reminder() {
    Intent intent  = new Intent(getActivity(), MainActivity.class);

    AlarmManager manager =(AlarmManager) getActivity().getSystemService(Activity.ALARM_SERVICE);
    PendingIntent pendingIntent = PendingIntent.getService(getActivity().getApplicationContext(),
            0,intent, 0);
    Calendar cal=Calendar.getInstance();
    cal.set(Calendar.HOUR_OF_DAY, 8); 
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    manager.setRepeating(AlarmManager.RTC_WAKEUP,cal.getTimeInMillis(),24*60*60*1000,pendingIntent);
}

出于测试目的，我手动设置了 hour/minute/second，但显然我需要从日期 String 中提取它。

Answer 1

你需要先写一个IntentService。这是一个示例，您可以编写用于在 processNotification 函数中显示通知的代码。

public class NotificationIntentService extends IntentService {

    private static final String ACTION_START = "ACTION_START";

    public NotificationIntentService() {
        super(NotificationIntentService.class.getSimpleName());
    }

    public static Intent createIntentStartNotificationService(Context context) {
        Intent intent = new Intent(context, NotificationIntentService.class);
        intent.setAction(ACTION_START);
        return intent;
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        try {
            String action = intent.getAction();
            if (ACTION_START.equals(action))
                processNotification();

        } finally {
            WakefulBroadcastReceiver.completeWakefulIntent(intent);
        }
    }

    private void processNotification() {
        Intent resultIntent=new Intent(this, MainActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, resultIntent, 0);
        Notification nBuilder = new Notification.Builder(this)
                .setContentTitle("Don't miss! ")
                .setTicker("Notification!")
                .setContentIntent(pIntent)
                .setDefaults(Notification.DEFAULT_SOUND)
                .setAutoCancel(true)
                .setSmallIcon(R.drawable.my_logo)
                .setContentText("7 days left till your appointment...")
                .build();
        NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        nBuilder.flags |=Notification.FLAG_AUTO_CANCEL;
        notificationManager.notify(1, nBuilder);
    }
}

然后创建一个NotificationEventReceiver

public class NotificationEventReceiver extends WakefulBroadcastReceiver {

    private static final String ACTION_START_NOTIFICATION_SERVICE = "ACTION_START_NOTIFICATION_SERVICE";

    public static void setupAlarm(Context context, long interval) {
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        PendingIntent alarmIntent = getStartPendingIntent(context);

        alarmManager.setRepeating(AlarmManager.RTC, System.currentTimeMillis(), interval, alarmIntent);
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Intent serviceIntent = null;
        if (ACTION_START_NOTIFICATION_SERVICE.equals(action)) {
            serviceIntent = NotificationIntentService.createIntentStartNotificationService(context);
        }

        if (serviceIntent != null) {
            startWakefulService(context, serviceIntent);
        }
    }

    private static PendingIntent getStartPendingIntent(Context context) {
        Intent intent = new Intent(context, NotificationEventReceiver.class);
        intent.setAction(ACTION_START_NOTIFICATION_SERVICE);
        return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    }
}

还有 NotificationServiceStarterReceiver

public final class NotificationServiceStarterReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        long interval = getIntent().getLongExtra("alarm_interval", 0);
        NotificationEventReceiver.setupAlarm(context, interval);
    }
}

将这些添加到 AndroidManifest.xml 内的 <application> 标签中

<service
    android:name="YourPackage.NotificationIntentService"
    android:enabled="true"
    android:exported="false" />

<receiver android:name="YourPackage.BroadcastReceiver.NotificationEventReceiver" />
<receiver android:name="YourPackage.BroadcastReceiver.NotificationServiceStarterReceiver">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
        <action android:name="android.intent.action.TIMEZONE_CHANGED" />
        <action android:name="android.intent.action.TIME_SET" />
    </intent-filter>
</receiver>

现在，您可以从 Activity 中调用 onCreate 函数中的 setupAlarm()。

NotificationEventReceiver.setupAlarm(getApplicationContext(), interval);

您需要在清单中添加 WAKE_LOCK 权限。

<uses-permission android:name="android.permission.WAKE_LOCK" />

这里你看你可以通过interval下一个要显示的通知。明智地使用 interval。您可以考虑将约会的当前状态保存在数据库中，然后在必要时通过传递下一个警报的适当间隔来触发警报。就是这个主意。

更新

所以在您的情况下，您不想在用户注销时显示通知。所以在这种情况下，您可以考虑保留一个 SharedPreference 来存储登录状态。您可以根据存储的值调用 processNotification 函数。

所以伪代码可能是这样的。

if(pref.getBoolean("login_status", false)) {
    // If the login status is true, process the notification
    processNotification();
} else {
    // Do nothing
}

Android 中自定义通知的确切时间

Exact time for custom notifications in Android

android

alarmmanager

android-service

android-notifications