我有一些代码可以下载“当前”对象的JSON。但是这个代码需要被一个IntentService调用,每当闹钟响起时(当应用程序没有运行任何UI时),也需要被AsyncTask调用,而当应用程序正在运行时。
然而,我遇到了一个错误,Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.
。然而,我不明白为什么这个堆栈跟踪出现在不同的线程上。
我通过将所有共享代码复制并直接粘贴到DownloadDealService的onHandleIntent
方法中来消除了错误,但这非常混乱,而且我正在寻找一种更好的解决方案,不需要复制代码。
有什么方法可以消除这个错误,而不需要复制代码吗?谢谢。
public class DownloadDealService extends IntentService
{
...
@Override
protected void onHandleIntent(Intent intent)
{
Current todaysCurrent = Utils.downloadTodaysCurrent(); //<--- included for background info
String dateString = Utils.getMehHeadquartersDate(); //(omitted)
Utils.onDownloadCurrentCompleteWithAlarm(todaysCurrent, dateString); //<------ calling this...
}
}
public class Utils
{
// ...other methods ommitted...
//This method is not in the stack trace, but I included it for background information.
public static Current downloadTodaysCurrent()
{
//Set up Gson object... (omitted)
//Set up RestAdapter object... (omitted)
//Set up MehService class... (omitted)
//Download "Current" object from the internet.
Current current = mehService.current(MehService.API_KEY);
return current;
}
//Included for background info- this method is not in the stack trace.
public static void onDownloadCurrentComplete(Current result, String dateString)
{
if(result.getVideo() == null)
{
Log.e("HomePage", "Current was not added on TaskComplete");
return;
}
remainder(result, dateString);
}
public static void onDownloadCurrentCompleteWithAlarm(Current result, String dateString)
{
//Set alarm if download failed and exit this function... (omitted)
remainder(result, dateString);//<------ calling this...
Utils.sendMehNewDealNotification(App.getContext());
}
public static void remainder(Current result, String dateString)
{
Realm realm = RealmDatabase.getInstance();
//Add "Current" to Realm
Current current = Utils.addCurrentToRealm(result, realm); //<------ calling this...
}
public static Current addCurrentToRealm(Current current, Realm realm)
{
realm.beginTransaction(); //<---- Error is here
Current result = realm.copyToRealmOrUpdate(current);
realm.commitTransaction();
return result;
}
}
堆栈跟踪:
E/AndroidRuntime: FATAL EXCEPTION: IntentService[DownloadDealService]
Process: com.example.lexi.meh, PID: 13738
java.lang.IllegalStateException: Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.
at io.realm.Realm.checkIfValid(Realm.java:191)
at io.realm.Realm.beginTransaction(Realm.java:1449)
at com.example.lexi.meh.Utils.Utils.addCurrentToRealm(Utils.java:324)
at com.example.lexi.meh.Utils.Utils.remainder(Utils.java:644)
at com.example.lexi.meh.Utils.Utils.onDownloadCurrentCompleteWithAlarm(Utils.java:635)
at com.example.lexi.meh.Home.DownloadDealService.onHandleIntent(DownloadDealService.java:42)
at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.os.HandlerThread.run(HandlerThread.java:61)
我有一个AsyncTask,它也调用了一些Utils方法:
public class DownloadAsyncTask extends AsyncTask<Void, Integer, Current>
{
// ... (more methods ommitted)...
protected Current doInBackground(Void... voids)
{
return Utils.downloadTodaysCurrent(); //<---- shared Utils method
}
}
//Async class's callback in main activity:
public class HomePage extends AppCompatActivity implements DownloadAsyncTaskCallback, DownloadAsyncTaskGistCallback<Current, String>
{
// ... (more methods ommitted)...
public void onTaskComplete(Current result, String dateString)
{
Utils.onDownloadCurrentComplete(result, dateString);
}
}
onPostExecute()
回调将Realm对象传递到UI线程,然后从那里调用Util.java类的静态方法也是如此。 - Rock LeeIntentService
中使用Realm.getInstance(this)
并将其传递给Util方法来解决了这个问题(因为这些方法无法访问线程上下文)。现在,Util方法可以被多个线程使用,并且每个线程都有一个正确的Realm实例。 - Rock Lee