BetterAsyncTaskLoader from Bote

app/src/main/java/net/i2p/android/router/util/BetterAsyncTaskLoader.java

+package net.i2p.android.router.util;
+
+import android.content.Context;
+import android.support.v4.content.AsyncTaskLoader;
+
+public abstract class BetterAsyncTaskLoader<T> extends AsyncTaskLoader<T> {
+    protected T mData;
+
+    public BetterAsyncTaskLoader(Context context) {
+        super(context);
+    }
+
+    /**
+     * Called when there is new data to deliver to the client.  The
+     * super class will take care of delivering it; the implementation
+     * here just adds a little more logic.
+     */
+    @Override
+    public void deliverResult(T data) {
+        if (isReset()) {
+            // An async query came in while the loader is stopped.  We
+            // don't need the result.
+            if (data != null) {
+                releaseResources(data);
+            }
+        }
+
+        // Hold a reference to the old data so it doesn't get garbage collected.
+        // We must protect it until the new data has been delivered.
+        T oldData = mData;
+        mData = data;
+
+        if (isStarted()) {
+            // If the Loader is currently started, we can immediately
+            // deliver its results.
+            super.deliverResult(data);
+        }
+
+        // Invalidate the old data as we don't need it any more.
+        if (oldData != null && oldData != data) {
+            releaseResources(oldData);
+        }
+    }
+
+    /**
+     * Handles a request to start the Loader.
+     */
+    @Override
+    protected void onStartLoading() {
+        if (mData != null) {
+            // Deliver any previously loaded data immediately.
+            deliverResult(mData);
+        }
+
+        // Start watching for changes
+        onStartMonitoring();
+
+        if (takeContentChanged() || mData == null) {
+            // When the observer detects a change, it should call onContentChanged()
+            // on the Loader, which will cause the next call to takeContentChanged()
+            // to return true. If this is ever the case (or if the current data is
+            // null), we force a new load.
+            forceLoad();
+        }
+    }
+
+    /**
+     * Handles a request to stop the Loader.
+     */
+    @Override
+    protected void onStopLoading() {
+        // The Loader is in a stopped state, so we should attempt to cancel the 
+        // current load (if there is one).
+        cancelLoad();
+
+        // Note that we leave the observer as is. Loaders in a stopped state
+        // should still monitor the data source for changes so that the Loader
+        // will know to force a new load if it is ever started again.
+    }
+
+    /**
+     * Handles a request to completely reset the Loader.
+     */
+    @Override
+    protected void onReset() {
+        super.onReset();
+
+        // Ensure the loader has been stopped.
+        onStopLoading();
+
+        // At this point we can release the resources associated with 'mData'.
+        if (mData != null) {
+            releaseResources(mData);
+            mData = null;
+        }
+
+        // Stop monitoring for changes.
+        onStopMonitoring();
+    }
+
+    /**
+     * Handles a request to cancel a load.
+     */
+    @Override
+    public void onCanceled(T data) {
+        // Attempt to cancel the current asynchronous load.
+        super.onCanceled(data);
+
+        // The load has been canceled, so we should release the resources
+        // associated with 'data'.
+        releaseResources(data);
+    }
+
+    protected abstract void onStartMonitoring();
+    protected abstract void onStopMonitoring();
+
+    /**
+     * Helper function to take care of releasing resources associated
+     * with an actively loaded data set.
+     * For a simple List, there is nothing to do. For something like a Cursor, we 
+     * would close it in this method. All resources associated with the Loader
+     * should be released here.
+     */
+    protected abstract void releaseResources(T data);
+}