应用程序被终止后，无法使用WorkManager定期发送本地通知

Question

我正面临一个浪费时间的问题
我正在用本地SQLite数据库构建一个应用程序。例如，我希望此应用程序每隔15分钟向用户发送一次通知，其中包含来自SQLite数据库的一些数据。我已经成功地实现了这一点，只要应用程序正在运行或未被终止，但当应用程序被终止时，用户将不再看到通知。我正在两台真正的设备上测试这个应用程序

public Result doWork() {
    try {

      SqliteAssetHelper dbHelper = new SqliteAssetHelper(MainActivity.mcontext);
        mdatabase = dbHelper.getWritableDatabase();


        Cursor mCursor = mdatabase.query(BDH.BDHEntry.TABLE_NAME,
                new String[]{BDH.BDHEntry.COLUMN_HADITH_ID,BDH.BDHEntry.COLUMN_BOOK_NAME,
                        BDH.BDHEntry.COLUMN_DOOR_NAME, BDH.BDHEntry.COLUMN_NARRATORS, BDH.BDHEntry.COLUMN_CONTEXT},
                BDH.BDHEntry.COLUMN_BOOK_ID+"=?",new String[]{"1"},null,null, "RANDOM() LIMIT 1");

        if (mCursor != null) {
            mCursor.moveToFirst();
            if (mCursor.getCount() > 0) {
                while (mCursor.isAfterLast() == false) { //You need to check if cursor doesnot contain last row
                    hadithID = mCursor.getString(mCursor.getColumnIndex("HadithID"));
                    book = mCursor.getString(mCursor.getColumnIndex("BookName"));
                    door = mCursor.getString(mCursor.getColumnIndex("DoorName"));
                    mCursor.moveToNext();
                }
            }
        }

        Intent intentActivity = new Intent(MainActivity.mcontext, HadithActivity.class)
                .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
        intentActivity.putExtra("id", hadithID );
        PendingIntent contentIntent = PendingIntent.getActivity(MainActivity.mcontext, 0, intentActivity, PendingIntent.FLAG_UPDATE_CURRENT);

        notificationManager = NotificationManagerCompat.from(MainActivity.mcontext);
        Notification notification = new NotificationCompat.Builder(MainActivity.mcontext,CHANNEL_ID)
                .setSmallIcon(R.drawable.book)
                .setContentTitle(book)
                .setContentText(door)
                .setPriority(NotificationCompat.PRIORITY_HIGH)
                .setAutoCancel(true)
                .setCategory(NotificationCompat.CATEGORY_CALL)
                .setContentIntent(contentIntent)
                .build();

        notificationManager.notify(notificationID, notification);
        return Result.success();

    }
    catch (Throwable throwable)
    {
        return Result.retry();
    }
}

在主要活动中，我使用上一个通知程序每15分钟显示一次：-

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mcontext = this;


    //creating constraints
    Constraints constraints = new Constraints.Builder()
            .setTriggerContentMaxDelay(1, TimeUnit.MINUTES)
            .build();


    PeriodicWorkRequest showHadithEveryHour = new PeriodicWorkRequest.Builder(HadithNotifier.class, 15, TimeUnit.MINUTES)
            .setConstraints(constraints)
            .build();
    WorkManager.getInstance(this).enqueue(showHadithEveryHour);
    }

当我更改通知程序类代码以显示不带任何值的日志消息时，logcat中的worker的结果是Success

Log.d(TAG,"Work Manager is working");

Answer 1

至少，从这个类中删除所有对Main Activity.mcontext的引用。更好的做法是完全从应用程序中删除mbackground，因为这是内存泄漏。

您的Worker构造函数被传递一个Context。在字段中保留它，并使用doWork（）方法中的Context。