added file observer to get notified when files are deleted: fixes #396

src/eu/siacs/conversations/persistance/FileBackend.java

@@ -72,9 +72,7 @@ public class FileBackend {
 	public DownloadableFile getFile(Message message,
 			boolean decrypted) {
 		StringBuilder filename = new StringBuilder();
-		filename.append(Environment.getExternalStoragePublicDirectory(
+		filename.append(getConversationsDirectory());
-				Environment.DIRECTORY_PICTURES).getAbsolutePath());
-		filename.append("/Conversations/");
 		filename.append(message.getUuid());
 		if ((decrypted) || (message.getEncryption() == Message.ENCRYPTION_NONE)) {
 			filename.append(".webp");
@@ -87,6 +85,11 @@ public class FileBackend {
 		}
 		return new DownloadableFile(filename.toString());
 	}
+	
+	public static String getConversationsDirectory() {
+		return Environment.getExternalStoragePublicDirectory(
+				Environment.DIRECTORY_PICTURES).getAbsolutePath()+"/Conversations/";
+	}
 
 	public Bitmap resize(Bitmap originalBitmap, int size) {
 		int w = originalBitmap.getWidth();

src/eu/siacs/conversations/services/XmppConnectionService.java

@@ -76,6 +76,7 @@ import android.net.NetworkInfo;
 import android.net.Uri;
 import android.os.Binder;
 import android.os.Bundle;
+import android.os.FileObserver;
 import android.os.IBinder;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
@@ -143,6 +144,16 @@ public class XmppConnectionService extends Service {
 			startService(intent);
 		}
 	};
+	
+	private FileObserver fileObserver = new FileObserver(FileBackend.getConversationsDirectory()) {
+		
+		@Override
+		public void onEvent(int event, String path) {
+			if (event == FileObserver.DELETE) {
+				markFileDeleted(path.split("\\.")[0]);
+			}
+		}
+	};
 
 	private final IBinder mBinder = new XmppConnectionBinder();
 	private OnStatusChanged statusListener = new OnStatusChanged() {
@@ -424,6 +435,7 @@ public class XmppConnectionService extends Service {
 
 		getContentResolver().registerContentObserver(
 				ContactsContract.Contacts.CONTENT_URI, true, contactObserver);
+		this.fileObserver.startWatching();
 		this.pgpServiceConnection = new OpenPgpServiceConnection(
 				getApplicationContext(), "org.sufficientlysecure.keychain");
 		this.pgpServiceConnection.bindToService();
@@ -813,6 +825,20 @@ public class XmppConnectionService extends Service {
 			}
 		}
 	}
+	
+	private void markFileDeleted(String uuid) {
+		for(Conversation conversation : getConversations()) {
+			for(Message message : conversation.getMessages()) {
+				if (message.getType() == Message.TYPE_IMAGE && message.getEncryption() != Message.ENCRYPTION_PGP && message.getUuid().equals(uuid)) {
+					if (!getFileBackend().isFileAvailable(message)) {
+						message.setDownloadable(new DeletedDownloadable());
+						updateConversationUi();
+					}
+					return;
+				}
+			}
+		}
+	}
 
 	public void populateWithOrderedConversations(List<Conversation> list) {
 		populateWithOrderedConversations(list, true);