can now view entry history and remove/restore previous versions. closes #298

.gitignore

@@ -172,3 +172,4 @@ src/java/Keepass2AndroidPluginSDK2/build/generated/mockable-Google-Inc.-Google-A
 /src/java/KP2AKdbLibrary/app/.cxx
 /src/ActionViewFilterTest
 /docs/gdrive-verification
+/src/MegaTest

src/keepass2android/EntryActivity.cs

@@ -93,6 +93,7 @@ namespace keepass2android
 	{
 		public const String KeyEntry = "entry";
         public const String KeyRefreshPos = "refresh_pos";
+        public const String KeyEntryHistoryIndex = "entry_history_index";
 		public const String KeyActivateKeyboard = "activate_keyboard";
 		public const String KeyGroupFullPath = "groupfullpath_key";
 
@@ -101,13 +102,14 @@ namespace keepass2android
 	    
 
 
-        public static void Launch(Activity act, PwEntry pw, int pos, AppTask appTask, ActivityFlags? flags = null)
+        public static void Launch(Activity act, PwEntry pw, int pos, AppTask appTask, ActivityFlags? flags = null, int historyIndex=-1)
 		{
 			Intent i = new Intent(act, typeof(EntryActivity));
 
             var db = App.Kp2a.FindDatabaseForElement(pw);
 			i.PutExtra(KeyEntry, new ElementAndDatabaseId(db, pw).FullId);
 			i.PutExtra(KeyRefreshPos, pos);
+            i.PutExtra(KeyEntryHistoryIndex, historyIndex);
 
 		    if (App.Kp2a.CurrentDb != db)
 		    {
@@ -135,7 +137,10 @@ namespace keepass2android
 			_activityDesign = new ActivityDesign(this);
 		}
 
+		//this is the entry we display. Note that it might be an element from a History list in case _historyIndex >= 0
 	    public PwEntry Entry;
+		//if _historyIndex >=0, _historyParentEntry stores the PwEntry which contains the history entry "Entry"
+        private PwEntry _historyParentEntry;
 
 		private PasswordFont _passwordFont = new PasswordFont();
 
@@ -183,7 +188,7 @@ namespace keepass2android
 
 		protected void SetupEditButtons() {
 			View edit =  FindViewById(Resource.Id.entry_edit);
-			if (App.Kp2a.CurrentDb.CanWrite)
+			if (App.Kp2a.CurrentDb.CanWrite && _historyIndex < 0)
 			{
 				edit.Visibility = ViewStates.Visible;
 				edit.Click += (sender, e) =>
@@ -421,16 +426,41 @@ namespace keepass2android
             ElementAndDatabaseId dbAndElementId = new ElementAndDatabaseId(i.GetStringExtra(KeyEntry));
 			PwUuid uuid = new PwUuid(MemUtil.HexStringToByteArray(dbAndElementId.ElementIdString));
 			_pos = i.GetIntExtra(KeyRefreshPos, -1);
+            _historyIndex = i.GetIntExtra(KeyEntryHistoryIndex, -1);
 
 			AppTask = AppTask.GetTaskInOnCreate(savedInstanceState, Intent);
 
 			Entry = db.EntriesById[uuid];
-			
-			// Refresh Menu contents in case onCreateMenuOptions was called before Entry was set
+
+            if (_historyIndex >= 0 && _historyIndex < Entry.History.UCount)
+            {
+                _historyParentEntry = Entry;
+                Entry = Entry.History.Skip(_historyIndex).First();
+                FindViewById<Button>(Resource.Id.btn_restore_history).Click += (sender, args) =>
+                {
+                    RestoreFromHistory();
+                    SaveHistoryChangeAndFinish();
+                };
+                FindViewById<Button>(Resource.Id.btn_remove_history).Click += (sender, args) =>
+                {
+                    RemoveFromHistory();
+                    SaveHistoryChangeAndFinish();
+				};
+
+
+            }
+            else
+            {
+                // Update last access time.
+                Entry.Touch(false);
+                FindViewById<Button>(Resource.Id.btn_restore_history).Visibility = ViewStates.Gone;
+                FindViewById<Button>(Resource.Id.btn_remove_history).Visibility = ViewStates.Gone;
+			}
+
+            // Refresh Menu contents in case onCreateMenuOptions was called before Entry was set
 			ActivityCompat.InvalidateOptionsMenu(this);
 
-			// Update last access time.
-			Entry.Touch(false);
+			
 
 			if (PwDefs.IsTanEntry(Entry) 
                 && prefs.GetBoolean(GetString(Resource.String.TanExpiresOnUse_key), Resources.GetBoolean(Resource.Boolean.TanExpiresOnUse_default)) 
@@ -462,7 +492,39 @@ namespace keepass2android
 			AppTask.CompleteOnCreateEntryActivity(this);
 		}
 
-		private void NotifyPluginsOnOpen()
+        private void RemoveFromHistory()
+        {
+            _historyParentEntry.History.RemoveAt((uint)_historyIndex);
+            _historyParentEntry.Touch(true, false);
+		}
+
+        private void RestoreFromHistory()
+        {
+            var db = App.Kp2a.FindDatabaseForElement(_historyParentEntry);
+			_historyParentEntry.RestoreFromBackup((uint)_historyIndex, db.KpDatabase);
+            _historyParentEntry.Touch(true, false);
+		}
+
+        private void SaveHistoryChangeAndFinish()
+        {
+            PwGroup parent = _historyParentEntry.ParentGroup;
+            if (parent != null)
+            {
+                // Mark parent group dirty (title might have changed etc.)
+                App.Kp2a.DirtyGroups.Add(parent);
+            }
+
+			var saveTask = new SaveDb(this, App.Kp2a, App.Kp2a.FindDatabaseForElement(Entry), new ActionOnFinish(this, (success, message, activity) =>
+            {
+                activity.SetResult(KeePass.ExitRefresh);
+                activity.Finish();
+            }));
+
+            ProgressTask pt = new ProgressTask(App.Kp2a, this, saveTask);
+            pt.Run();
+		}
+
+        private void NotifyPluginsOnOpen()
 		{
 			Intent i = new Intent(Strings.ActionOpenEntry);
 			i.PutExtra(Strings.ExtraSender, PackageName);
@@ -854,12 +916,41 @@ namespace keepass2android
 
 			PopulateBinaries();
 
+            PopulatePreviousVersions();
+
 			SetPasswordStyle();
 		}
 
-		
+        private void PopulatePreviousVersions()
+        {
+			ViewGroup historyGroup = (ViewGroup)FindViewById(Resource.Id.previous_versions);
+            int index = 0;
+			foreach (var previousVersion in Entry.History)
+			{
+				
 
-		protected override void OnDestroy()
+
+                Button btn = new Button(this);
+                btn.Text = getDateTime(previousVersion.LastModificationTime);
+
+				//copy variable from outer scope for capturing it below.
+                var index1 = index;
+                btn.Click += (sender, args) =>
+                {
+                    EntryActivity.Launch(this, this.Entry, this._pos, this.AppTask, null, index1);
+                };
+
+				historyGroup.AddView(btn);
+
+                index++;
+
+
+            }
+			FindViewById(Resource.Id.entry_history_container).Visibility = Entry.History.Any() ? ViewStates.Visible : ViewStates.Gone;
+		}
+
+
+        protected override void OnDestroy()
 		{
 			NotifyPluginsOnClose();
 			if (_pluginActionReceiver != null)
@@ -1083,6 +1174,7 @@ namespace keepass2android
 	    private ExportBinaryProcessManager _exportBinaryProcessManager;
         private bool _showPasswordDefault;
         private bool _showTotpDefault;
+        private int _historyIndex;
 
         protected override void OnSaveInstanceState(Bundle outState)
 	    {

src/keepass2android/EntryEditActivity.cs

@@ -797,7 +797,7 @@ namespace keepass2android
 			}
 
 		}
-
+		
 		public void Reload() {
 			//this reload ìs necessary to overcome a strange problem with the extra string fields which get lost
 			//somehow after re-creating the activity. Maybe a Mono for Android bug?

src/keepass2android/Resources/layout/entry_view_contents.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/entry_table"
     android:layout_height="wrap_content"
     android:layout_width="fill_parent"
@@ -348,32 +349,7 @@
           style="@style/EntryItem" />
     </LinearLayout>
   </LinearLayout>
-  <LinearLayout
-    android:id="@+id/entryfield_container_modified"
-            style="@style/EntryEditSingleLine_container">
-    <ImageView
-        style="@style/EntryEditSingleLine_ImageView"
-        android:src="@drawable/ic_entry_modified" />
-
-    <LinearLayout
-        
-        android:layout_height="wrap_content"
-        android:layout_width="fill_parent"
-        android:orientation="vertical">
-      <!-- Modified -->
-      <TextView
-          android:id="@+id/entry_modified_label"
-          android:layout_width="fill_parent"
-          android:layout_height="wrap_content"
-          android:text="@string/entry_modified"
-          style="@style/EntryFieldHeader" />
-      <TextView
-          android:id="@+id/entry_modified"
-          android:layout_width="fill_parent"
-          android:layout_height="wrap_content"
-          style="@style/EntryItem" />
-    </LinearLayout>
-  </LinearLayout>
+  
   <LinearLayout
     android:id="@+id/entryfield_container_expires"
             style="@style/EntryEditSingleLine_container">
@@ -400,4 +376,77 @@
           style="@style/EntryItem" />
     </LinearLayout>
   </LinearLayout>
+  
+  
+  <LinearLayout
+    android:id="@+id/entryfield_container_modified"
+            style="@style/EntryEditSingleLine_container">
+    <ImageView
+        style="@style/EntryEditSingleLine_ImageView"
+        android:src="@drawable/ic_entry_modified" />
+
+    <LinearLayout
+        
+        android:layout_height="wrap_content"
+        android:layout_width="fill_parent"
+        android:orientation="vertical">
+      <!-- Modified -->
+      <TextView
+          android:id="@+id/entry_modified_label"
+          android:layout_width="fill_parent"
+          android:layout_height="wrap_content"
+          android:text="@string/entry_modified"
+          style="@style/EntryFieldHeader" />
+      <TextView
+          android:id="@+id/entry_modified"
+          android:layout_width="fill_parent"
+          android:layout_height="wrap_content"
+          style="@style/EntryItem" />
+		  
+		<Button android:id="@+id/btn_restore_history" 
+			android:layout_width="fill_parent"
+			android:layout_height="wrap_content"
+			android:drawableLeft="@drawable/ic_entry_history"
+			android:text="@string/restore_history"
+			
+			/>
+			
+			<Button android:id="@+id/btn_remove_history" 
+			android:layout_width="fill_parent"
+			android:layout_height="wrap_content"
+			android:drawableLeft="@android:drawable/ic_menu_delete"
+			android:text="@string/remove_history"
+			
+			/>
+    </LinearLayout>
+  </LinearLayout>
+  
+  <LinearLayout
+    android:id="@+id/entry_history_container"
+            style="@style/EntryEditSingleLine_container">
+    <ImageView
+        style="@style/EntryEditSingleLine_ImageView"
+        android:src="@drawable/ic_entry_history" />
+
+    <LinearLayout
+        android:layout_height="wrap_content"
+        android:layout_width="fill_parent"
+        android:orientation="vertical">
+
+      <!-- previous versions-->
+      <TextView
+        
+          android:layout_width="fill_parent"
+          android:layout_height="wrap_content"
+          android:text="@string/entry_history"
+          style="@style/EntryFieldHeader" />
+      <LinearLayout
+          android:id="@+id/previous_versions"
+          android:layout_width="fill_parent"
+          android:layout_height="wrap_content"
+          android:orientation="vertical" />
+    </LinearLayout>
+  </LinearLayout>
+  
+		
 </LinearLayout>

src/keepass2android/Resources/values/strings.xml

@@ -136,6 +136,7 @@
   <string name="entry_user_name">User Name</string>
   <string name="entry_extra_strings">Extra string fields</string>
   <string name="entry_binaries">File attachments</string>
+  <string name="entry_history">Previous versions</string>
   <string name="error_can_not_handle_uri">Keepass2Android cannot handle this URI.</string>
   <string name="error_could_not_create_group">Error creating group.</string>
   <string name="error_could_not_create_parent">Could not create parent directory.</string>
@@ -828,8 +829,9 @@
   <string name="child_db_Enabled_title">Open automatically</string>
   <string name="database_file_heading">Database file</string>
   <string name="if_device_text">Enable for %1$s</string>
-  
 
+  <string name="restore_history">Restore this version</string>
+  <string name="remove_history">Remove this version</string>
   
   <string name="DbUnlockedChannel_name">Database unlocked</string>
   <string name="DbUnlockedChannel_desc">Notification about the database being unlocked</string>

src/keepass2android/app/App.cs

@@ -1138,7 +1138,8 @@ namespace keepass2android
 	    {
             foreach (var db in OpenDatabases)
             {
-                if (db.Elements.Contains(element))
+				//we compare UUIDs and not by reference. this is more robust and works with history items as well
+                if (db.Elements.Any(e => e.Uuid?.Equals(element.Uuid) == true))
                     return db;
             }
 	        return null;

src/keepass2android/keepass2android-app.csproj

@@ -399,6 +399,7 @@
     <AndroidResource Include="Resources\drawable-mdpi\ic_arrow_back_white_24dp.png" />
     <AndroidResource Include="Resources\drawable-mdpi\ic_cross.png" />
     <AndroidResource Include="Resources\drawable-mdpi\ic_entry_attachments.png" />
+	<AndroidResource Include="Resources\drawable-mdpi\ic_entry_history.png" />
     <AndroidResource Include="Resources\drawable-mdpi\ic_entry_comments.png" />
     <AndroidResource Include="Resources\drawable-mdpi\ic_entry_created.png" />
     <AndroidResource Include="Resources\drawable-mdpi\ic_entry_expires.png" />
@@ -987,6 +988,9 @@
   <ItemGroup>
     <AndroidResource Include="Resources\drawable-xhdpi\ic_entry_attachments.png" />
   </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\drawable-xhdpi\ic_entry_history.png" />
+  </ItemGroup>
   <ItemGroup>
     <AndroidResource Include="Resources\drawable-xhdpi\ic_entry_comments.png" />
   </ItemGroup>