diff --git a/app/src/main/java/org/traccar/client/DatabaseHelper.java b/app/src/main/java/org/traccar/client/DatabaseHelper.java
index 4390fac..f549c20 100644
--- a/app/src/main/java/org/traccar/client/DatabaseHelper.java
+++ b/app/src/main/java/org/traccar/client/DatabaseHelper.java
@@ -31,8 +31,7 @@ public class DatabaseHelper extends SQLiteOpenHelper {
     public static final String DATABASE_NAME = "traccar.db";
 
     public interface DatabaseHandler<T> {
-        void onSuccess(T result);
-        void onFailure(RuntimeException error);
+        void onComplete(boolean success, T result);
     }
 
     private static abstract class DatabaseAsyncTask<T> extends AsyncTask<Void, Void, T> {
@@ -58,11 +57,7 @@ public class DatabaseHelper extends SQLiteOpenHelper {
 
         @Override
         protected void onPostExecute(T result) {
-            if (error == null) {
-                handler.onSuccess(result);
-            } else {
-                handler.onFailure(error);
-            }
+            handler.onComplete(error == null, result);
         }
     }
 
diff --git a/app/src/main/java/org/traccar/client/RequestManager.java b/app/src/main/java/org/traccar/client/RequestManager.java
index 3842b0f..0de7c2f 100644
--- a/app/src/main/java/org/traccar/client/RequestManager.java
+++ b/app/src/main/java/org/traccar/client/RequestManager.java
@@ -27,8 +27,7 @@ public class RequestManager {
     private static final int TIMEOUT = 15 * 1000;
 
     public interface RequestHandler {
-        void onSuccess();
-        void onFailure();
+        void onComplete(boolean success);
     }
 
     private static class RequestAsyncTask extends AsyncTask<String, Void, Boolean> {
@@ -46,11 +45,7 @@ public class RequestManager {
 
         @Override
         protected void onPostExecute(Boolean result) {
-            if (result) {
-                handler.onSuccess();
-            } else {
-                handler.onFailure();
-            }
+            handler.onComplete(result);
         }
     }
 
diff --git a/app/src/main/java/org/traccar/client/TrackingController.java b/app/src/main/java/org/traccar/client/TrackingController.java
index d9a8eb3..a27ed1e 100644
--- a/app/src/main/java/org/traccar/client/TrackingController.java
+++ b/app/src/main/java/org/traccar/client/TrackingController.java
@@ -122,18 +122,15 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
         lock();
         databaseHelper.insertPositionAsync(position, new DatabaseHelper.DatabaseHandler<Void>() {
             @Override
-            public void onSuccess(Void result) {
-                if (isOnline && isWaiting) {
-                    read();
-                    isWaiting = false;
+            public void onComplete(boolean success, Void result) {
+                if (success) {
+                    if (isOnline && isWaiting) {
+                        read();
+                        isWaiting = false;
+                    }
                 }
                 unlock();
             }
-
-            @Override
-            public void onFailure(RuntimeException error) {
-                unlock();
-            }
         });
     }
 
@@ -142,20 +139,18 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
         lock();
         databaseHelper.selectPositionAsync(new DatabaseHelper.DatabaseHandler<Position>() {
             @Override
-            public void onSuccess(Position result) {
-                if (result != null) {
-                    send(result);
+            public void onComplete(boolean success, Position result) {
+                if (success) {
+                    if (result != null) {
+                        send(result);
+                    } else {
+                        isWaiting = true;
+                    }
                 } else {
-                    isWaiting = true;
+                    retry();
                 }
                 unlock();
             }
-
-            @Override
-            public void onFailure(RuntimeException error) {
-                retry();
-                unlock();
-            }
         });
     }
 
@@ -164,14 +159,12 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
         lock();
         databaseHelper.deletePositionAsync(position.getId(), new DatabaseHelper.DatabaseHandler<Void>() {
             @Override
-            public void onSuccess(Void result) {
-                read();
-                unlock();
-            }
-
-            @Override
-            public void onFailure(RuntimeException error) {
-                retry();
+            public void onComplete(boolean success, Void result) {
+                if (success) {
+                    read();
+                } else {
+                    retry();
+                }
                 unlock();
             }
         });
@@ -187,15 +180,12 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
 
         RequestManager.sendRequestAsync(request, new RequestManager.RequestHandler() {
             @Override
-            public void onSuccess() {
-                delete(position);
-                unlock();
-            }
-
-            @Override
-            public void onFailure() {
-                StatusActivity.addMessage(context.getString(R.string.status_send_fail));
-                retry();
+            public void onComplete(boolean success) {
+                if (success) {
+                    delete(position);
+                } else {
+                    retry();
+                }
                 unlock();
             }
         });