Realm对象只能在创建它们的线程上访问

Realm对象只能在创建它们的线程上访问_ Volley和AsyncTask(Realm objects can only be accessed on the thread they were created _ Volley and AsyncTask)

我已经解决了这个问题的类似问题，但找不到答案

所以问题1 ，问题2和问题3

我的应用程序流程是按钮点击，使用Volley按如下方式请求网络。只包括相关的代码。在以下行中访问ActivityCustomer时出错

Object obj = realmObj.where(ExplorerFolderData.class) .equalTo(Constants.DBPARENTID,"0") .or() .equalTo(Constants.DBPARENTID,"-1") .findAllAsync();

错误：

由：java.lang.IllegalStateException引起：Realm从不正确的线程访问。领域对象只能在创建它们的线程上访问。

1） MyApplication

public class MyApplication extends Application { private static Context appContext; @Override public void onCreate() { super.onCreate(); RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(this) .name(Realm.DEFAULT_REALM_NAME) .schemaVersion(0) .deleteRealmIfMigrationNeeded() .build(); Realm.setDefaultConfiguration(realmConfiguration); appContext = getApplicationContext(); } public static Context getAppContext(){ return appContext; } }

2）接口OnAsyncTaskComplition

//This interface will get back the status to Activity/Fragment public interface OnAsyncTaskComplition { public void networkResponse(ResultObject responseObject); }

3） 网络处理器

public class NetworkProcessor{ private OnAsyncTaskComplition mCaller; public NetworkProcessor(Activity activity){ //setting caller Activity/Fragment to get back data mCaller=(OnAsyncTaskComplition)activity; processNetworkData(); } //Method for Volley Network Procesing public void processNetworkData(){ JsonObjectRequest jsonObjReq = new JsonObjectRequest(methodReq,urlBuffer.toString(),null, new Response.Listener<JSONObject>(){ @Override public void onResponse(JSONObject response) { JsonProcessor jsonProcessor=new JsonProcessor(); mCaller.networkResponse(jsonProcessor.getThingList(response)); } }, new Response.ErrorListener(){ @Override public void onErrorResponse(VolleyError error) { //Handle error also back to caller } }); } }

4） JsonProcessor

public class JsonProcessor { public status void getThingList(JSONObject response){ boolean status=false; try{ RealmProcessor realmProcessor=RealmProcessor.with(MyApplication.getAppContext()); Realm realmObj = realmProcessor.getRealm(); //Code for setting values to RealmObject class ExplorerFolderData realmObj.beginTransaction(); realmObj.copyToRealm(ExplorerFolderData RealmObject which has values populated); realmObj.commitTransaction(); status=true; }catch(Exception e){ } } }

5） RealmProcessor

public class RealmProcessor { private static RealmProcessor instance; private Realm realm; private RealmProcessor(Context context) { realm = Realm.getDefaultInstance(); } public static RealmProcessor with(Context context) { if (instance == null) { instance = new RealmProcessor(context); } return instance; } public Realm getRealm() { return realm; } }

6）Activity类ActivityCustomer

public class ActivityCustomer extends AppBaseActivity implements OnAsyncTaskComplition { //Method called on Button click private void callNetwork(){ new NetworkProcessor(this); } @Override public void networkResponse(ResultObject responseObject) { new ExplorerDBOperation().execute(); } class ExplorerDBOperation extends AsyncTask<Void,Boolean,Boolean> { ProgressDialog dialog; @Override protected Boolean doInBackground(Void... params) { RealmProcessor realmProcessor=RealmProcessor.with(MyApplication.getAppContext()); Realm realmObj = realmProcessor.getRealm(); //ERROR OVER HERE Object obj = realmObj.where(ExplorerFolderData.class) .equalTo(Constants.DBPARENTID,"0") .or() .equalTo(Constants.DBPARENTID,"-1") .findAllAsync(); return true; } }

我在Activity和JsonProcessor类中使用相同的行获取领域对象。我在这里犯了什么错误。

I already gone through these similar questions for the issue, but could not find the answer

SO question1 , SO question2 and SO question3

My application flow is on button click, network is requested as follows using Volley. Included only relevant code . Error getting in ActivityCustomer in the following line

Object obj = realmObj.where(ExplorerFolderData.class) .equalTo(Constants.DBPARENTID,"0") .or() .equalTo(Constants.DBPARENTID,"-1") .findAllAsync();

Error:

Caused by: java.lang.IllegalStateException: Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.

1) MyApplication

2) Interface OnAsyncTaskComplition

//This interface will get back the status to Activity/Fragment public interface OnAsyncTaskComplition { public void networkResponse(ResultObject responseObject); }

3) NetworkProcessor

4) JsonProcessor

5) RealmProcessor

6) Activity class ActivityCustomer

I am getting realm object using the same line in Activity as well as JsonProcessor class. What is the mistake I am making over here.

最满意答案

你使用单例设置的方式只有1个Realm实例。

如果你调用realmProcessor.getRealm(); 在线程A中，然后在线程B中再次调用它们，它们返回相同的实例。 Realm不允许在线程之间共享实例。由于AsyncTask的doInBackground在单独的线程上运行，因此这不起作用。

更改为此将消除错误。但是你有一些重新设计要做。

@Override protected Boolean doInBackground(Void... params) { Realm realmObj = Realm.getDefaultInstance(); try { Object obj = realmObj.where(ExplorerFolderData.class) .equalTo(Constants.DBPARENTID,"0") .or() .equalTo(Constants.DBPARENTID,"-1") .findAll(); } catch (Exception ex) { // handle error } finally { realmObj.close(); } return true; }

请注意，您负责每个领域实例。这意味着您必须手动确保您完成每个实例后关闭它。 AsyncTasks的一个常见做法是将doInBackground操作包装在try / catch / finally中，并关闭finally块中的realm实例以确保它被关闭。

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The way you are set up with the singleton you have only 1 Realm instance.

If you call realmProcessor.getRealm(); in thread A, and then call it again in thread B, they get back the same instance. Realm does not allow sharing instances between threads. Since the AsyncTask's doInBackground runs on a separate thread, this is not working.

Changing to this will rid you of the error. However you have some redesigning to do.

Note that you are responsible for each and every realm instance. This means that you must manually ensure that you close every instance once you're done with it. A common practice for AsyncTasks is that you wrap your doInBackground operations in a try/catch/finally and close the realm instance in the finally block to ensure it gets closed.

See more in the docs

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