我正在寻找一种在 Settings 中创建 preference 的方法，以便在 Android 中的一天中的特定时间(由用户在设置中设置)发送通知应用程序。我看过不同的线程，例如 this ，但是这在 Android Oreo 中不起作用。

有人可以帮我解决这个问题或给我指点教程吗？

最佳答案

在查看不同的帖子和对 AlarmManager 的一些研究之后实现，这对我有用。

它的基础是 this发布和安排重复警报 Android Documentation .

这是我当前的实现:

我有一个 SwitchPreference和一个 TimePicker实现是 Settings

SwitchPreference 询问用户是否要启用重复每日通知。

TimePicker 用于设置通知时间。

在MainActivity的 OnCreate方法或您正在阅读 SharedPreferences 的任何地方这样做:

PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
Boolean dailyNotify = sharedPref.getBoolean(SettingsActivity.KEY_PREF_DAILY_NOTIFICATION, true);
PackageManager pm = this.getPackageManager();
ComponentName receiver = new ComponentName(this, DeviceBootReceiver.class);
Intent alarmIntent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

// if user enabled daily notifications
if (dailyNotify) {
    //region Enable Daily Notifications
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.set(Calendar.HOUR_OF_DAY, sharedPref.getInt("dailyNotificationHour", 7));
    calendar.set(Calendar.MINUTE, sharedPref.getInt("dailyNotificationMin", 15));
    calendar.set(Calendar.SECOND, 1);
    // if notification time is before selected time, send notification the next day
    if (calendar.before(Calendar.getInstance())) {
        calendar.add(Calendar.DATE, 1);
    }
    if (manager != null) {
        manager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
                AlarmManager.INTERVAL_DAY, pendingIntent);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            manager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
        }
    }
    //To enable Boot Receiver class
    pm.setComponentEnabledSetting(receiver,
            PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
            PackageManager.DONT_KILL_APP);
    //endregion
} else { //Disable Daily Notifications
    if (PendingIntent.getBroadcast(this, 0, alarmIntent, 0) != null && manager != null) {
        manager.cancel(pendingIntent);
        //Toast.makeText(this,"Notifications were disabled",Toast.LENGTH_SHORT).show();
    }
    pm.setComponentEnabledSetting(receiver,
            PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
            PackageManager.DONT_KILL_APP);
}

接下来添加AlarmReceiver实现 BroadcastReceiver 的类像这样:

public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {

    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(Objects.requireNonNull(context));
    SharedPreferences.Editor sharedPrefEditor = prefs.edit();

    NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    Intent notificationIntent = new Intent(context, MainActivity.class);

    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
            | Intent.FLAG_ACTIVITY_SINGLE_TOP);

    PendingIntent pendingI = PendingIntent.getActivity(context, 0,
            notificationIntent, 0);
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel("default",
                    "Daily Notification",
                    NotificationManager.IMPORTANCE_DEFAULT);
            channel.setDescription("Daily Notification");
            if (nm != null) {
                nm.createNotificationChannel(channel);
            }
        }
        NotificationCompat.Builder b = new NotificationCompat.Builder(context, "default");
        b.setAutoCancel(true)
                .setDefaults(NotificationCompat.DEFAULT_ALL)
                .setWhen(System.currentTimeMillis())
                .setSmallIcon(R.mipmap.ic_launcher_foreground)
                .setTicker("{Time to watch some cool stuff!}")
                .setContentTitle("My Cool App")
                .setContentText("Time to watch some cool stuff!")
                .setContentInfo("INFO")
                .setContentIntent(pendingI);

        if (nm != null) {
            nm.notify(1, b.build());
            Calendar nextNotifyTime = Calendar.getInstance();
            nextNotifyTime.add(Calendar.DATE, 1);
            sharedPrefEditor.putLong("nextNotifyTime", nextNotifyTime.getTimeInMillis());
            sharedPrefEditor.apply();
        }
    }
}

系统将关闭 AlarmManager如果设备关闭或重新启动，请在 BOOT COMPLETE 上重新启动它添加这个类:

public class DeviceBootReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    if (Objects.equals(intent.getAction(), "android.intent.action.BOOT_COMPLETED")) {
        // on device boot complete, reset the alarm
        Intent alarmIntent = new Intent(context, AlarmReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, alarmIntent, 0);

        AlarmManager manager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        final SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(Objects.requireNonNull(context));

        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.set(Calendar.HOUR_OF_DAY, sharedPref.getInt("dailyNotificationHour", 7));
        calendar.set(Calendar.MINUTE, sharedPref.getInt("dailyNotificationMin", 15));
        calendar.set(Calendar.SECOND, 1);

        Calendar newC = new GregorianCalendar();
        newC.setTimeInMillis(sharedPref.getLong("nextNotifyTime", Calendar.getInstance().getTimeInMillis()));

        if (calendar.after(newC)) {
            calendar.add(Calendar.HOUR, 1);
        }

        if (manager != null) {
            manager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
                    AlarmManager.INTERVAL_DAY, pendingIntent);
        }
    }
}
}

最后不要忘记将这些权限添加到 AndroidManidest :

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

并在 AndroidManifest 中注册您的接收器

<application
    <!--YOUR APPLICATION STUFF-->

    <receiver android:name=".DeviceBootReceiver"
        android:enabled="false">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
    </receiver>
    <receiver android:name=".AlarmReceiver" />

Notification应该在 TimePicker 指定的一天中的特定时间由此设置如果用户启用了 SwitchPreference .

更新(2022 年 8 月):适用于 Android 12 设备

要使其适用于 Android 12 设备，您需要修改 pendingIntent从 0 到 FLAG_IMMUTABLE 的标志像这样:

PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, FLAG_IMMUTABLE);

在 Build.VERSION_CODES.R 之前，PendingIntents 被假定为默认可变，除非设置了 FLAG_IMMUTABLE。从 Build.VERSION_CODES.S 开始，需要在创建时使用 FLAG_IMMUTABLE 或 FLAG_MUTABLE 明确指定 PendingIntents 的可变性。 您可以找到有关 PendingIntent 标志的更多信息 here

关于android - 如何在 Android Oreo 中的特定时间在 Android 上发出通知？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51343550/