Merge branch '851-refresher-memory-leak' into 'master'

Fix memory leaks caused by periodic view refreshing tasks

This branch implements @goapunk's suggested solution to #851. Credit goes to @ernir for finding the bug and the initial solution, and @goapunk for the improved solution - I just did a quick implementation so we can get this fixed as quickly as possible.

Closes #851

See merge request !473

briar-android/src/main/java/org/briarproject/briar/android/blog/BasePostFragment.java

 package org.briarproject.briar.android.blog;
 
 import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
 import android.support.annotation.CallSuper;
 import android.support.annotation.UiThread;
 import android.view.LayoutInflater;
@@ -20,7 +22,7 @@ import javax.annotation.Nullable;
 
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
-import static org.briarproject.briar.android.util.UiUtils.MIN_RESOLUTION;
+import static org.briarproject.briar.android.util.UiUtils.MIN_DATE_RESOLUTION;
 
 @UiThread
 @MethodsNotNullByDefault
@@ -32,8 +34,9 @@ abstract class BasePostFragment extends BaseFragment {
 	private static final Logger LOG =
 			Logger.getLogger(BasePostFragment.class.getName());
 
+	private final Handler handler = new Handler(Looper.getMainLooper());
+
 	protected MessageId postId;
-	private View view;
 	private ProgressBar progressBar;
 	private BlogPostViewHolder ui;
 	private BlogPostItem post;
@@ -50,7 +53,7 @@ abstract class BasePostFragment extends BaseFragment {
 		if (p == null) throw new IllegalStateException("No post ID in args");
 		postId = new MessageId(p);
 
-		view = inflater.inflate(R.layout.fragment_blog_post, container,
+		View view = inflater.inflate(R.layout.fragment_blog_post, container,
 				false);
 		progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
 		progressBar.setVisibility(VISIBLE);
@@ -83,21 +86,19 @@ abstract class BasePostFragment extends BaseFragment {
 		refresher = new Runnable() {
 			@Override
 			public void run() {
-				if (ui == null) return;
 				LOG.info("Updating Content...");
-
 				ui.updateDate(post.getTimestamp());
-				view.postDelayed(refresher, MIN_RESOLUTION);
+				handler.postDelayed(refresher, MIN_DATE_RESOLUTION);
 			}
 		};
 		LOG.info("Adding Handler Callback");
-		view.postDelayed(refresher, MIN_RESOLUTION);
+		handler.postDelayed(refresher, MIN_DATE_RESOLUTION);
 	}
 
 	private void stopPeriodicUpdate() {
-		if (refresher != null && ui != null) {
+		if (refresher != null) {
 			LOG.info("Removing Handler Callback");
-			view.removeCallbacks(refresher);
+			handler.removeCallbacks(refresher);
 		}
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedFragment.java

@@ -105,6 +105,7 @@ public class FeedFragment extends BaseFragment implements
 	public void onStart() {
 		super.onStart();
 		feedController.onStart();
+		list.startPeriodicUpdate();
 		loadPersonalBlog();
 		loadBlogPosts(false);
 	}
@@ -157,7 +158,6 @@ public class FeedFragment extends BaseFragment implements
 						handleDbException(exception);
 					}
 				});
-		list.startPeriodicUpdate();
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/util/UiUtils.java

@@ -33,7 +33,7 @@ import static android.text.format.DateUtils.WEEK_IN_MILLIS;
 
 public class UiUtils {
 
-	public static final long MIN_RESOLUTION = MINUTE_IN_MILLIS;
+	public static final long MIN_DATE_RESOLUTION = MINUTE_IN_MILLIS;
 	public static final int TEASER_LENGTH = 320;
 	public static final float GREY_OUT = 0.5f;
 
@@ -51,15 +51,16 @@ public class UiUtils {
 				FORMAT_SHOW_DATE | FORMAT_ABBREV_TIME | FORMAT_ABBREV_MONTH;
 
 		long diff = System.currentTimeMillis() - time;
-		if (diff < MIN_RESOLUTION) return ctx.getString(R.string.now);
+		if (diff < MIN_DATE_RESOLUTION) return ctx.getString(R.string.now);
 		if (diff >= DAY_IN_MILLIS && diff < WEEK_IN_MILLIS) {
 			// also show time when older than a day, but newer than a week
 			return DateUtils.getRelativeDateTimeString(ctx, time,
-					MIN_RESOLUTION, WEEK_IN_MILLIS, flags).toString();
+					MIN_DATE_RESOLUTION, WEEK_IN_MILLIS, flags).toString();
 		}
 		// otherwise just show "...ago" or date string
 		return DateUtils.getRelativeTimeSpanString(time,
-				System.currentTimeMillis(), MIN_RESOLUTION, flags).toString();
+				System.currentTimeMillis(),
+				MIN_DATE_RESOLUTION, flags).toString();
 	}
 
 	public static SpannableStringBuilder getTeaser(Context ctx, Spanned body) {

briar-android/src/main/java/org/briarproject/briar/android/view/BriarRecyclerView.java

@@ -2,6 +2,8 @@ package org.briarproject.briar.android.view;
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.os.Handler;
+import android.os.Looper;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.Adapter;
 import android.util.AttributeSet;
@@ -17,14 +19,15 @@ import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
-import static org.briarproject.briar.android.util.UiUtils.MIN_RESOLUTION;
+import static org.briarproject.briar.android.util.UiUtils.MIN_DATE_RESOLUTION;
 
 public class BriarRecyclerView extends FrameLayout {
 
-	private static final long DEFAULT_REFRESH_INTERVAL = MIN_RESOLUTION;
 	private static final Logger LOG =
 			Logger.getLogger(BriarRecyclerView.class.getName());
 
+	private final Handler handler = new Handler(Looper.getMainLooper());
+
 	private RecyclerView recyclerView;
 	private TextView emptyView;
 	private ProgressBar progressBar;
@@ -192,18 +195,19 @@ public class BriarRecyclerView extends FrameLayout {
 			@Override
 			public void run() {
 				LOG.info("Updating Content...");
-				recyclerView.getAdapter().notifyDataSetChanged();
-				postDelayed(refresher, DEFAULT_REFRESH_INTERVAL);
+				Adapter adapter = recyclerView.getAdapter();
+				adapter.notifyItemRangeChanged(0, adapter.getItemCount());
+				handler.postDelayed(refresher, MIN_DATE_RESOLUTION);
 			}
 		};
 		LOG.info("Adding Handler Callback");
-		postDelayed(refresher, DEFAULT_REFRESH_INTERVAL);
+		handler.postDelayed(refresher, MIN_DATE_RESOLUTION);
 	}
 
 	public void stopPeriodicUpdate() {
 		if (refresher != null) {
 			LOG.info("Removing Handler Callback");
-			removeCallbacks(refresher);
+			handler.removeCallbacks(refresher);
 		}
 	}