Merge pull request #20943 from wordpress-mobile/hackweek/database-anr

Fix a potential issue related to lifecycle

Author: jarvislin

WordPress/src/main/java/org/wordpress/android/datasets/AsyncTaskExecutor.kt

@@ -0,0 +1,51 @@
+package org.wordpress.android.datasets
+
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+/**
+ * Helper class to handle asynchronous I/O tasks using coroutines
+ * @see <a href="https://github.com/wordpress-mobile/WordPress-Android/pull/20937">Introduction</a>
+ */
+object AsyncTaskExecutor {
+    /**
+     * Execute a data loading task in the IO thread and handle the result on the main thread
+     */
+    @JvmStatic
+    fun <T> executeIo(scope: CoroutineScope, backgroundTask: () -> T, callback: AsyncTaskCallback<T>) {
+        execute(scope, Dispatchers.IO, backgroundTask, callback)
+    }
+
+    /**
+     * Execute a data loading task in the default thread and handle the result on the main thread
+     */
+    @JvmStatic
+    fun <T> executeDefault(scope: CoroutineScope, backgroundTask: () -> T, callback: AsyncTaskCallback<T>) {
+        execute(scope, Dispatchers.Default, backgroundTask, callback)
+    }
+
+    private fun <T> execute(
+        scope: CoroutineScope,
+        dispatcher: CoroutineDispatcher,
+        backgroundTask: () -> T,
+        callback: AsyncTaskCallback<T>
+    ) {
+        scope.launch(dispatcher) {
+            // handle the background task
+            val result = backgroundTask()
+
+            withContext(Dispatchers.Main) {
+                // handle the result on the main thread
+                callback.onTaskFinished(result)
+            }
+        }
+    }
+
+    interface AsyncTaskCallback<T> {
+        fun onTaskFinished(result: T)
+    }
+}
+

WordPress/src/main/java/org/wordpress/android/datasets/AsyncTaskHandler.kt

@@ -153,6 +153,7 @@
 
 import javax.inject.Inject;
 
+import static androidx.lifecycle.LifecycleOwnerKt.getLifecycleScope;
 import static org.wordpress.android.fluxc.generated.AccountActionBuilder.newUpdateSubscriptionNotificationPostAction;
 import static org.wordpress.android.ui.reader.ReaderActivityLauncher.OpenUrlType.INTERNAL;
 
@@ -1923,7 +1924,8 @@ private ReaderPostAdapter getPostAdapter() {
                     mImageManager,
                     mUiHelpers,
                     mNetworkUtilsWrapper,
-                    mIsTopLevel
+                    mIsTopLevel,
+                    getLifecycleScope(this)
             );
             mPostAdapter.setOnFollowListener(this);
             mPostAdapter.setOnPostSelectedListener(this);

WordPress/src/main/java/org/wordpress/android/ui/reader/ReaderPostListFragment.java

@@ -15,12 +15,13 @@
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
+import androidx.lifecycle.LifecycleCoroutineScope;
 import androidx.recyclerview.widget.RecyclerView;
 
 import org.wordpress.android.R;
 import org.wordpress.android.WordPress;
 import org.wordpress.android.analytics.AnalyticsTracker;
-import org.wordpress.android.datasets.AsyncTaskHandler;
+import org.wordpress.android.datasets.AsyncTaskExecutor;
 import org.wordpress.android.datasets.ReaderPostTable;
 import org.wordpress.android.datasets.ReaderTagTable;
 import org.wordpress.android.fluxc.store.AccountStore;
@@ -82,11 +83,13 @@
 import kotlin.jvm.functions.Function1;
 import kotlin.jvm.functions.Function2;
 import kotlin.jvm.functions.Function3;
+import kotlinx.coroutines.CoroutineScope;
 
 public class ReaderPostAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
     private final ImageManager mImageManager;
     private final UiHelpers mUiHelpers;
     private final NetworkUtilsWrapper mNetworkUtilsWrapper;
+    private final CoroutineScope mScope;
     private ReaderTag mCurrentTag;
     private long mCurrentBlogId;
     private long mCurrentFeedId;
@@ -372,7 +375,8 @@ private void toggleFollowButton(
             return;
         }
 
-        AsyncTaskHandler.load(
+        AsyncTaskExecutor.executeIo(
+                mScope,
                 () -> !ReaderTagTable.isFollowedTagName(currentTag.getTagSlug()),
                 isAskingToFollow -> {
                     final String slugForTracking = currentTag.getTagSlug();
@@ -688,7 +692,8 @@ public ReaderPostAdapter(
             ImageManager imageManager,
             UiHelpers uiHelpers,
             @NonNull final NetworkUtilsWrapper networkUtilsWrapper,
-            boolean isMainReader
+            boolean isMainReader,
+            LifecycleCoroutineScope scope
     ) {
         super();
         ((WordPress) context.getApplicationContext()).component().inject(this);
@@ -699,6 +704,7 @@ public ReaderPostAdapter(
         mNetworkUtilsWrapper = networkUtilsWrapper;
         mAvatarSzSmall = context.getResources().getDimensionPixelSize(R.dimen.avatar_sz_small);
         mIsMainReader = isMainReader;
+        mScope = scope;
 
         int displayWidth = DisplayUtils.getWindowPixelWidth(context);
         int cardMargin = context.getResources().getDimensionPixelSize(R.dimen.reader_card_margin);