Fix for issues with drag/drop

1 files changed, 112 insertions, 0 deletions

diff --git a/app/src/main/java/github/daneren2005/dsub/util/DownloadFileItemHelperCallback.java b/app/src/main/java/github/daneren2005/dsub/util/DownloadFileItemHelperCallback.java
new file mode 100644
index 00000000..4074fece
--- /dev/null
+++ b/app/src/main/java/github/daneren2005/dsub/util/DownloadFileItemHelperCallback.java
@@ -0,0 +1,112 @@
+package github.daneren2005.dsub.util;
+
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.helper.ItemTouchHelper;
+
+import org.eclipse.jetty.util.ArrayQueue;
+
+import java.util.Queue;
+
+import github.daneren2005.dsub.adapter.SectionAdapter;
+import github.daneren2005.dsub.fragments.SubsonicFragment;
+import github.daneren2005.dsub.service.DownloadFile;
+import github.daneren2005.dsub.service.DownloadService;
+import github.daneren2005.dsub.view.SongView;
+import github.daneren2005.dsub.view.UpdateView;
+
+public class DownloadFileItemHelperCallback extends ItemTouchHelper.SimpleCallback {
+	private SubsonicFragment fragment;
+	private boolean mainList;
+
+	private BackgroundTask pendingTask = null;
+	private Queue pendingOperations = new ArrayQueue();
+
+	public DownloadFileItemHelperCallback(SubsonicFragment fragment, boolean mainList) {
+		super(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT);
+		this.fragment = fragment;
+		this.mainList = mainList;
+	}
+
+	@Override
+	public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder fromHolder, RecyclerView.ViewHolder toHolder) {
+		int from = fromHolder.getAdapterPosition();
+		int to = toHolder.getAdapterPosition();
+		getSectionAdapter().notifyItemMoved(from, to);
+
+		synchronized (pendingOperations) {
+			pendingOperations.add(new Pair<>(from, to));
+			updateDownloadService();
+		}
+		return true;
+	}
+
+	@Override
+	public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
+		SongView songView = (SongView) ((UpdateView.UpdateViewHolder) viewHolder).getUpdateView();
+		DownloadFile downloadFile = songView.getDownloadFile();
+
+		getSectionAdapter().removeItem(downloadFile);
+		synchronized (pendingOperations) {
+			pendingOperations.add(downloadFile);
+			updateDownloadService();
+		}
+	}
+
+	public DownloadService getDownloadService() {
+		return fragment.getDownloadService();
+	}
+	public SectionAdapter getSectionAdapter() {
+		return fragment.getCurrentAdapter();
+	}
+
+	private void updateDownloadService() {
+		if(pendingTask == null) {
+			final DownloadService downloadService = getDownloadService();
+			if(downloadService == null) {
+				return;
+			}
+
+			pendingTask = new SilentBackgroundTask<Void>(downloadService) {
+				@Override
+				protected Void doInBackground() throws Throwable {
+					boolean running = true;
+					while(running) {
+						Object nextOperation = null;
+						synchronized (pendingOperations) {
+							if(!pendingOperations.isEmpty()) {
+								nextOperation = pendingOperations.remove();
+							}
+						}
+
+						if(nextOperation != null) {
+							if(nextOperation instanceof Pair) {
+								Pair<Integer, Integer> swap = (Pair) nextOperation;
+								downloadService.swap(mainList, swap.getFirst(), swap.getSecond());
+							} else if(nextOperation instanceof DownloadFile) {
+								DownloadFile downloadFile = (DownloadFile) nextOperation;
+								if(mainList) {
+									downloadService.remove(downloadFile);
+								} else {
+									downloadService.removeBackground(downloadFile);
+								}
+							}
+						} else {
+							running = false;
+						}
+					}
+
+					synchronized (pendingOperations) {
+						pendingTask = null;
+
+						// Start a task if this is non-empty.  Means someone added while we were running operations
+						if(!pendingOperations.isEmpty()) {
+							updateDownloadService();
+						}
+					}
+					return null;
+				}
+			};
+			pendingTask.execute();
+		}
+	}
+}