pin lock page modifications

src/App/App.cs

@@ -76,6 +76,12 @@ namespace Bit.App
             {
                 CheckLockAsync(false);
             }
+
+            var lockPage = Current.MainPage.Navigation.ModalStack.LastOrDefault() as LockPinPage;
+            if(lockPage != null)
+            {
+                lockPage.PinControl.Entry.Focus();
+            }
         }
 
         private async Task CheckLockAsync(bool forceLock)

src/App/Controls/PinControl.cs

@@ -24,8 +24,8 @@ namespace Bit.App.Controls
             Entry = new ExtendedEntry
             {
                 Keyboard = Keyboard.Numeric,
-                IsVisible = false,
+                MaxLength = 4,
-                MaxLength = 4
+                Margin = new Thickness(0, int.MaxValue, 0, 0)
             };
             Entry.SetBinding<PinPageModel>(Xamarin.Forms.Entry.TextProperty, s => s.PIN);
             Entry.TextChanged += PinEntry_TextChanged;

src/App/Pages/LockFingerprintPage.cs

@@ -55,6 +55,11 @@ namespace Bit.App.Pages
             Content = stackLayout;
         }
 
+        protected override bool OnBackButtonPressed()
+        {
+            return false;
+        }
+
         protected override void OnAppearing()
         {
             base.OnAppearing();

src/App/Pages/LockPinPage.cs

@@ -46,7 +46,7 @@ namespace Bit.App.Pages
             {
                 Padding = new Thickness(30, 40),
                 Spacing = 10,
-                Children = { PinControl.Label, PinControl.Entry, logoutButton }
+                Children = { PinControl.Label, logoutButton, PinControl.Entry }
             };
 
             Title = "Verify PIN";
@@ -54,6 +54,12 @@ namespace Bit.App.Pages
             BindingContext = Model;
         }
 
+
+        protected override bool OnBackButtonPressed()
+        {
+            return false;
+        }
+
         protected override void OnAppearing()
         {
             base.OnAppearing();