Add option to always merge on conflict, closes https://github.com/PhilippC/keepass2android/issues/1218

src/Kp2aBusinessLogic/database/edit/SaveDB.cs

@@ -21,6 +21,7 @@ using System.Security.Cryptography;
 using Android.App;
 using Android.Content;
 using Android.OS;
+using Android.Preferences;
 using Java.Lang;
 using KeePassLib;
 using KeePassLib.Serialization;
@@ -37,7 +38,7 @@ namespace keepass2android
 	    private readonly Database _db;
 	    private readonly bool _dontSave;
 
-		/// <summary>
+        /// <summary>
 		/// stream for reading the data from the original file. If this is set to a non-null value, we know we need to sync
 		/// </summary>
 		private readonly Stream _streamForOrigFile;
@@ -51,7 +52,7 @@ namespace keepass2android
 			_ctx = ctx;
 			_app = app;
 			_dontSave = dontSave;
-		}
+        }
 		
 		/// <summary>
 		/// Constructor for sync
@@ -129,6 +130,17 @@ namespace keepass2android
 					{
 						Kp2aLog.Log("Conflict. " + hasStreamForOrigFile + " " + hasChangeFast + " " + hasHashChanged);
 
+						bool alwaysMerge = (PreferenceManager.GetDefaultSharedPreferences(Application.Context)
+                            .GetBoolean("AlwaysMergeOnConflict", false));
+
+						if (alwaysMerge)
+                        {
+                            MergeAndFinish(fileStorage, ioc);
+						}
+                        else
+                        {
+                            
+
 						//ask user...
 						_app.AskYesNoCancel(UiStringKey.TitleSyncQuestion, UiStringKey.MessageSyncQuestion, 
 							UiStringKey.YesSynchronize,
@@ -136,16 +148,7 @@ namespace keepass2android
 							//yes = sync
 							(sender, args) =>
 							{
-								Action runHandler = () =>
-									{
-										//note: when synced, the file might be downloaded once again from the server. Caching the data
-										//in the hashing function would solve this but increases complexity. I currently assume the files are 
-										//small.
-										MergeIn(fileStorage, ioc);
-										PerformSaveWithoutCheck(fileStorage, ioc);
-                                        _db.UpdateGlobals();
-										Finish(true);
-									};
+								Action runHandler = () => { MergeAndFinish(fileStorage, ioc); };
 								RunInWorkerThread(runHandler);
 							},
 							//no = overwrite
@@ -164,6 +167,8 @@ namespace keepass2android
 							},
 							_ctx
 							);
+                        }
+						
 					}
 					else
 					{
@@ -193,7 +198,18 @@ namespace keepass2android
 			
 		}
 
-		private void RunInWorkerThread(Action runHandler)
+        private void MergeAndFinish(IFileStorage fileStorage, IOConnectionInfo ioc)
+        {
+            //note: when synced, the file might be downloaded once again from the server. Caching the data
+            //in the hashing function would solve this but increases complexity. I currently assume the files are 
+            //small.
+            MergeIn(fileStorage, ioc);
+            PerformSaveWithoutCheck(fileStorage, ioc);
+            _db.UpdateGlobals();
+            Finish(true);
+        }
+
+        private void RunInWorkerThread(Action runHandler)
 		{
 			try
 			{

src/keepass2android/Resources/values/config.xml

@@ -50,6 +50,7 @@
 
   <!--  Preference settings -->
   <string name="AutoReturnFromQuery_key">AutoReturnFromQuery_key</string>
+  <string name="AlwaysMergeOnConflict_key">AlwaysMergeOnConflict</string>
   <string name="NoDalVerification_key">NoDalVerification_key</string>
   <string name="InlineSuggestions_key">InlineSuggestions_key</string>
   <string name="algorithm_key">algorithm</string>

src/keepass2android/Resources/values/strings.xml

@@ -311,6 +311,8 @@
 	<string name="please_note">Please note</string>
 	<string name="contributors">Contributors</string>
   <string name="regular_expression">Regular expression</string>
+  <string name="AlwaysMergeOnConflict_title">Always merge on conflict</string>
+  <string name="AlwaysMergeOnConflict_summary">When Keepass2Android detects that the remote file was modified, always merge the local changes with the remote changes.</string>
   <string name="TanExpiresOnUse_title">TAN expires on use</string>
   <string name="TanExpiresOnUse_summary">Mark TAN entries expired when using them</string>
   <string name="ShowUsernameInList_title">Display username in list</string>

src/keepass2android/Resources/xml/preferences.xml

@@ -576,6 +576,14 @@
   android:key="@string/SyncAfterQuickUnlock_key" />
 
       <CheckBoxPreference
+        android:enabled="true"
+        android:persistent="true"
+        android:summary="@string/AlwaysMergeOnConflict_summary"
+        android:defaultValue="false"
+        android:title="@string/AlwaysMergeOnConflict_title"
+        android:key="@string/AlwaysMergeOnConflict_key" />
+
+      <CheckBoxPreference
   android:key="@string/TanExpiresOnUse_key"
   android:title="@string/TanExpiresOnUse_title"
   android:summary="@string/TanExpiresOnUse_summary"