Load forum post text lazily.

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumActivity.java

@@ -54,7 +54,7 @@ public class ForumActivity extends
 
 	@Override
 	protected ThreadItemAdapter<ForumPostItem> createAdapter() {
-		return new ThreadItemAdapter<>(this);
+		return new ThreadItemAdapter<>(this, this);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumPostItem.java

@@ -6,10 +6,10 @@ import org.briarproject.briar.api.forum.ForumPostHeader;
 import javax.annotation.concurrent.NotThreadSafe;
 
 @NotThreadSafe
-class ForumPostItem extends ThreadItem {
+public class ForumPostItem extends ThreadItem {
 
-	ForumPostItem(ForumPostHeader h, String text) {
+	ForumPostItem(ForumPostHeader h) {
-		super(h.getId(), h.getParentId(), text, h.getTimestamp(), h.getAuthor(),
+		super(h.getId(), h.getParentId(), null, h.getTimestamp(), h.getAuthor(),
 				h.getAuthorInfo(), h.isRead());
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumViewModel.java

@@ -91,9 +91,7 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			ForumPostReceivedEvent f = (ForumPostReceivedEvent) e;
 			if (f.getGroupId().equals(groupId)) {
 				LOG.info("Forum post received, adding...");
-				ForumPostItem item =
+				addItem(new ForumPostItem(f.getHeader()), false);
-						new ForumPostItem(f.getHeader(), f.getText());
-				addItem(item, false);
 			}
 		} else if (e instanceof ForumInvitationResponseReceivedEvent) {
 			ForumInvitationResponseReceivedEvent f =
@@ -139,22 +137,14 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			List<ForumPostHeader> headers =
 					forumManager.getPostHeaders(txn, groupId);
 			logDuration(LOG, "Loading headers", start);
-			start = now();
 			List<ForumPostItem> items = new ArrayList<>();
 			for (ForumPostHeader header : headers) {
-				items.add(loadItem(txn, header));
+				items.add(new ForumPostItem(header));
 			}
-			logDuration(LOG, "Loading bodies and creating items", start);
 			return items;
 		}, this::setItems);
 	}
 
-	private ForumPostItem loadItem(Transaction txn, ForumPostHeader header)
-			throws DbException {
-		String text = forumManager.getPostText(txn, header.getId());
-		return new ForumPostItem(header, text);
-	}
-
 	@Override
 	public void createAndStoreMessage(String text,
 			@Nullable MessageId parentId) {
@@ -175,21 +165,17 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			@Nullable MessageId parentId, LocalAuthor author) {
 		cryptoExecutor.execute(() -> {
 			LOG.info("Creating forum post...");
-			ForumPost msg = forumManager.createLocalPost(groupId, text,
+			storePost(forumManager.createLocalPost(groupId, text,
-					timestamp, parentId, author);
+					timestamp, parentId, author));
-			storePost(msg, text);
 		});
 	}
 
-	private void storePost(ForumPost msg, String text) {
+	private void storePost(ForumPost msg) {
 		runOnDbThread(false, txn -> {
 			long start = now();
 			ForumPostHeader header = forumManager.addLocalPost(txn, msg);
 			logDuration(LOG, "Storing forum post", start);
-			txn.attach(() -> {
+			txn.attach(() -> addItem(new ForumPostItem(header), true));
-				ForumPostItem item = new ForumPostItem(header, text);
-				addItem(item, true);
-			});
 		}, this::handleException);
 	}
 
@@ -229,4 +215,9 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 		});
 	}
 
+	@Override
+	protected String getMessageText(Transaction txn, MessageId m)
+			throws DbException {
+		return forumManager.getPostText(txn, m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupActivity.java

@@ -15,7 +15,6 @@ import org.briarproject.briar.android.privategroup.memberlist.GroupMemberListAct
 import org.briarproject.briar.android.privategroup.reveal.RevealContactsActivity;
 import org.briarproject.briar.android.threaded.ThreadListActivity;
 import org.briarproject.briar.android.threaded.ThreadListViewModel;
-import org.briarproject.briar.android.widget.LinkDialogFragment;
 import org.briarproject.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.nullsafety.ParametersNotNullByDefault;
 
@@ -56,7 +55,7 @@ public class GroupActivity extends
 
 	@Override
 	protected GroupMessageAdapter createAdapter() {
-		return new GroupMessageAdapter(this);
+		return new GroupMessageAdapter(this, this);
 	}
 
 	@Override
@@ -160,12 +159,6 @@ public class GroupActivity extends
 		if (isDissolved != null && !isDissolved) super.onReplyClick(item);
 	}
 
-	@Override
-	public void onLinkClick(String url){
-		LinkDialogFragment f = LinkDialogFragment.newInstance(url);
-		f.show(getSupportFragmentManager(), f.getUniqueTag());
-	}
-
 	private void setGroupEnabled(boolean enabled) {
 		sendController.setReady(enabled);
 		list.getRecyclerView().setAlpha(enabled ? 1f : 0.5f);

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupMessageAdapter.java

@@ -11,16 +11,19 @@ import org.briarproject.briar.android.threaded.ThreadPostViewHolder;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import androidx.annotation.LayoutRes;
+import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 @UiThread
 @NotNullByDefault
-class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
+public class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 
 	private boolean isCreator = false;
 
-	GroupMessageAdapter(ThreadItemListener<GroupMessageItem> listener) {
+	GroupMessageAdapter(LifecycleOwner lifecycleOwner,
-		super(listener);
+			ThreadItemListener<GroupMessageItem> listener) {
+		super(lifecycleOwner, listener);
 	}
 
 	@LayoutRes
@@ -30,6 +33,7 @@ class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 		return item.getLayout();
 	}
 
+	@NonNull
 	@Override
 	public BaseThreadItemViewHolder<GroupMessageItem> onCreateViewHolder(
 			ViewGroup parent, int type) {

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupMessageItem.java

@@ -1,11 +1,11 @@
 package org.briarproject.briar.android.privategroup.conversation;
 
 import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.threaded.ThreadItem;
+import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.briar.api.privategroup.GroupMessageHeader;
 
 import javax.annotation.Nullable;
@@ -16,7 +16,7 @@ import androidx.annotation.UiThread;
 
 @UiThread
 @NotThreadSafe
-class GroupMessageItem extends ThreadItem {
+public class GroupMessageItem extends ThreadItem {
 
 	private final GroupId groupId;
 

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupViewModel.java

@@ -284,4 +284,9 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		return isDissolved;
 	}
 
+	@Override
+	protected String getMessageText(Transaction txn, MessageId m)
+			throws DbException {
+		return privateGroupManager.getMessageText(txn, m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/JoinMessageItemViewHolder.java

@@ -9,6 +9,7 @@ import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListe
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 import static org.briarproject.briar.api.identity.AuthorInfo.Status.OURSELVES;
 
@@ -25,9 +26,9 @@ class JoinMessageItemViewHolder
 	}
 
 	@Override
-	public void bind(GroupMessageItem item,
+	public void bind(GroupMessageItem item, LifecycleOwner lifecycleOwner,
 			ThreadItemListener<GroupMessageItem> listener) {
-		super.bind(item, listener);
+		super.bind(item, lifecycleOwner, listener);
 
 		if (isCreator) bindForCreator((JoinMessageItem) item);
 		else bind((JoinMessageItem) item);

briar-android/src/main/java/org/briarproject/briar/android/threaded/BaseThreadItemViewHolder.java

@@ -10,17 +10,22 @@ import android.view.ViewGroup;
 import android.view.animation.AccelerateInterpolator;
 import android.widget.TextView;
 
-import org.briarproject.bramble.util.StringUtils;
+import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListener;
 import org.briarproject.briar.android.view.AuthorView;
 import org.briarproject.nullsafety.NotNullByDefault;
 
+import javax.annotation.Nullable;
+
 import androidx.annotation.CallSuper;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
 import androidx.recyclerview.widget.RecyclerView;
 
 import static androidx.core.content.ContextCompat.getColor;
+import static org.briarproject.bramble.util.StringUtils.trim;
 import static org.briarproject.briar.android.util.UiUtils.makeLinksClickable;
 
 @UiThread
@@ -33,6 +38,8 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 	protected final TextView textView;
 	private final ViewGroup layout;
 	private final AuthorView author;
+	@Nullable
+	private MessageId boundMessageId = null;
 
 	public BaseThreadItemViewHolder(View v) {
 		super(v);
@@ -43,8 +50,22 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 	}
 
 	@CallSuper
-	public void bind(I item, ThreadItemListener<I> listener) {
+	public void bind(I item, LifecycleOwner lifecycleOwner,
-		textView.setText(StringUtils.trim(item.getText()));
+			ThreadItemListener<I> listener) {
+		boundMessageId = item.getId();
+		String text = item.getText();
+		if (text == null) {
+			textView.setText(null);
+			LiveData<String> textLiveData = listener.loadItemText(item.getId());
+			textLiveData.observe(lifecycleOwner, t -> {
+				// Check that the ViewHolder hasn't been re-bound while loading
+				if (item.getId().equals(boundMessageId)) {
+					textView.setText(t);
+				}
+			});
+		} else {
+			textView.setText(trim(text));
+		}
 		Linkify.addLinks(textView, Linkify.WEB_URLS);
 		makeLinksClickable(textView, listener::onLinkClick);
 

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadItem.java

@@ -19,6 +19,7 @@ public abstract class ThreadItem implements MessageNode {
 	private final MessageId messageId;
 	@Nullable
 	private final MessageId parentId;
+	@Nullable
 	private final String text;
 	private final long timestamp;
 	private final Author author;
@@ -27,8 +28,8 @@ public abstract class ThreadItem implements MessageNode {
 	private boolean isRead, highlighted;
 
 	public ThreadItem(MessageId messageId, @Nullable MessageId parentId,
-			String text, long timestamp, Author author, AuthorInfo authorInfo,
+			@Nullable String text, long timestamp, Author author,
-			boolean isRead) {
+			AuthorInfo authorInfo, boolean isRead) {
 		this.messageId = messageId;
 		this.parentId = parentId;
 		this.text = text;
@@ -39,6 +40,7 @@ public abstract class ThreadItem implements MessageNode {
 		this.highlighted = false;
 	}
 
+	@Nullable
 	public String getText() {
 		return text;
 	}

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadItemAdapter.java

@@ -13,6 +13,8 @@ import javax.annotation.Nullable;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
 import androidx.recyclerview.widget.DiffUtil;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.ListAdapter;
@@ -27,9 +29,11 @@ public class ThreadItemAdapter<I extends ThreadItem>
 
 	static final int UNDEFINED = -1;
 
+	private final LifecycleOwner lifecycleOwner;
 	private final ThreadItemListener<I> listener;
 
-	public ThreadItemAdapter(ThreadItemListener<I> listener) {
+	public ThreadItemAdapter(LifecycleOwner lifecycleOwner,
+			ThreadItemListener<I> listener) {
 		super(new DiffUtil.ItemCallback<I>() {
 			@Override
 			public boolean areItemsTheSame(I a, I b) {
@@ -42,6 +46,7 @@ public class ThreadItemAdapter<I extends ThreadItem>
 						a.isRead() == b.isRead();
 			}
 		});
+		this.lifecycleOwner = lifecycleOwner;
 		this.listener = listener;
 	}
 
@@ -58,7 +63,7 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	public void onBindViewHolder(@NonNull BaseThreadItemViewHolder<I> ui,
 			int position) {
 		I item = getItem(position);
-		ui.bind(item, listener);
+		ui.bind(item, lifecycleOwner, listener);
 	}
 
 	int findItemPosition(MessageId id) {
@@ -136,8 +141,12 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	}
 
 	public interface ThreadItemListener<I> {
+
 		void onReplyClick(I item);
+
 		void onLinkClick(String url);
+
+		LiveData<String> loadItemText(MessageId m);
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadListActivity.java

@@ -257,4 +257,8 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 
 	protected abstract int getMaxTextLength();
 
+	@Override
+	public LiveData<String> loadItemText(MessageId m) {
+		return getViewModel().loadMessageText(m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadListViewModel.java

@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.crypto.CryptoExecutor;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
@@ -260,4 +261,14 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 		return scrollToItem.getAndSet(null);
 	}
 
+	public LiveData<String> loadMessageText(MessageId m) {
+		MutableLiveData<String> textLiveData = new MutableLiveData<>();
+		runOnDbThread(true, txn ->
+						textLiveData.postValue(getMessageText(txn, m)),
+				this::handleException);
+		return textLiveData;
+	}
+
+	protected abstract String getMessageText(Transaction txn, MessageId m)
+			throws DbException;
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadPostViewHolder.java

@@ -10,6 +10,7 @@ import org.briarproject.nullsafety.NotNullByDefault;
 import java.util.Locale;
 
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
@@ -40,8 +41,9 @@ public class ThreadPostViewHolder<I extends ThreadItem>
 	}
 
 	@Override
-	public void bind(I item, ThreadItemListener<I> listener) {
+	public void bind(I item, LifecycleOwner lifecycleOwner,
-		super.bind(item, listener);
+			ThreadItemListener<I> listener) {
+		super.bind(item, lifecycleOwner, listener);
 
 		for (int i = 0; i < lvls.length; i++) {
 			lvls[i].setVisibility(i < item.getLevel() ? VISIBLE : GONE);

briar-api/src/main/java/org/briarproject/briar/api/forum/event/ForumPostReceivedEvent.java

@@ -16,13 +16,10 @@ public class ForumPostReceivedEvent extends Event {
 
 	private final GroupId groupId;
 	private final ForumPostHeader header;
-	private final String text;
 
-	public ForumPostReceivedEvent(GroupId groupId, ForumPostHeader header,
+	public ForumPostReceivedEvent(GroupId groupId, ForumPostHeader header) {
-			String text) {
 		this.groupId = groupId;
 		this.header = header;
-		this.text = text;
 	}
 
 	public GroupId getGroupId() {
@@ -32,8 +29,4 @@ public class ForumPostReceivedEvent extends Event {
 	public ForumPostHeader getHeader() {
 		return header;
 	}
-
-	public String getText() {
-		return text;
-	}
 }

briar-core/src/main/java/org/briarproject/briar/forum/ForumManagerImpl.java

@@ -83,10 +83,7 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 		messageTracker.trackIncomingMessage(txn, m);
 
 		ForumPostHeader header = getForumPostHeader(txn, m.getId(), meta);
-		String text = getPostText(body);
+		txn.attach(new ForumPostReceivedEvent(m.getGroupId(), header));
-		ForumPostReceivedEvent event =
-				new ForumPostReceivedEvent(m.getGroupId(), header, text);
-		txn.attach(event);
 
 		return ACCEPT_SHARE;
 	}