Fixed green button color for API<21.

Fixed #60

app/src/main/java/org/secuso/privacyfriendlysudoku/ui/MainActivity.java

@@ -23,6 +23,7 @@ import android.app.DialogFragment;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
 import android.net.Uri;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
@@ -198,6 +199,11 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
             difficultyBar.setRating(GameDifficulty.getValidDifficultyList().indexOf(lastChosenDifficulty) + 1);
         }
 
+        if(Configuration.SCREENLAYOUT_SIZE_SMALL == (getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK)) {
+            difficultyBar.setScaleX(0.75f);
+            difficultyBar.setScaleY(0.75f);
+        }
+
         // on first create always check for loadable levels!
         SharedPreferences.Editor editor = settings.edit();
         editor.putBoolean("savesChanged", true);

app/src/main/java/org/secuso/privacyfriendlysudoku/ui/view/CreateSudokuSpecialButtonLayout.java

@@ -23,6 +23,7 @@ import android.app.DialogFragment;
 import android.app.FragmentManager;
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.drawable.Drawable;
@@ -58,6 +59,7 @@ public class CreateSudokuSpecialButtonLayout extends LinearLayout implements IHi
     Canvas canvas;
     FragmentManager fragmentManager;
     Context context;
+    float buttonMargin;
 
     OnClickListener listener = new OnClickListener() {
         @Override
@@ -95,6 +97,11 @@ public class CreateSudokuSpecialButtonLayout extends LinearLayout implements IHi
 
     public CreateSudokuSpecialButtonLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
+
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CreateSudokuSpecialButtonLayout);
+        buttonMargin = a.getDimension(R.styleable.CreateSudokuSpecialButtonLayout_createSudokuSpecialKeyboardMargin, 5f);
+        a.recycle();
+
         setWeightSum(fixedButtonsCount);
         this.context = context;
     }
@@ -117,7 +124,7 @@ public class CreateSudokuSpecialButtonLayout extends LinearLayout implements IHi
         if(gameController != null) {
             gameController.registerHighlightChangedListener(this);
         }
-         fixedButtons = new CreateSudokuSpecialButton[fixedButtonsCount];
+        fixedButtons = new CreateSudokuSpecialButton[fixedButtonsCount];
         LayoutParams p;
         int i = 0;
         //ArrayList<SudokuButtonType> type = (ArrayList<SudokuButtonType>) SudokuButtonType.getSpecialButtons();
@@ -127,9 +134,9 @@ public class CreateSudokuSpecialButtonLayout extends LinearLayout implements IHi
                 p = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, 1);
             } else {
                 p = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, 1);
-                fixedButtons[i].setPadding(25, 0, 25, 0);
+                fixedButtons[i].setPadding((int)buttonMargin*5, 0, (int)buttonMargin*5, 0);
             }
-            p.setMargins(5, 5, 5, 5);
+            p.setMargins((int)buttonMargin, (int)buttonMargin, (int)buttonMargin, (int)buttonMargin);
 
             //int width2 =width/(fixedButtonsCount);
             //p.width= width2-15;

app/src/main/java/org/secuso/privacyfriendlysudoku/ui/view/SudokuKeyboardLayout.java

@@ -17,7 +17,9 @@
 package org.secuso.privacyfriendlysudoku.ui.view;
 
 import android.content.Context;
+import android.content.res.TypedArray;
 import android.graphics.Canvas;
+import android.graphics.Color;
 import android.util.AttributeSet;
 import android.util.TypedValue;
 import android.view.Gravity;
@@ -42,6 +44,7 @@ public class SudokuKeyboardLayout extends LinearLayout implements IHighlightChan
     Symbol symbolsToUse = Symbol.Default;
     float normalTextSize = 20; // in sp
     LinearLayout [] layouts = new LinearLayout[2];
+    float buttonMargin;
 
     OnClickListener listener = new OnClickListener() {
         @Override
@@ -58,6 +61,11 @@ public class SudokuKeyboardLayout extends LinearLayout implements IHighlightChan
     public SudokuKeyboardLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
         this.attrs = attrs;
+
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SudokuKeyboardLayout);
+        buttonMargin = a.getDimension(R.styleable.SudokuKeyboardLayout_sudokuKeyboardMargin, 5f);
+        normalTextSize = a.getDimension(R.styleable.SudokuKeyboardLayout_sudokuKeyboardTextSize, 20f);
+        a.recycle();
     }
 
     public void setSymbols(Symbol s) {
@@ -85,7 +93,7 @@ public class SudokuKeyboardLayout extends LinearLayout implements IHighlightChan
                 p = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT, 1);
             }
             //if (i == 0) p.bottomMargin=10; else p.topMargin=10;
-            p.setMargins(0, 5, 0, 5);
+            p.setMargins(0, (int) buttonMargin, 0, (int) buttonMargin);
             layouts[i] = new LinearLayout(getContext(),null);
             layouts[i].setLayoutParams(p);
             layouts[i].setWeightSum(numberOfButtonsPerRow);
@@ -106,7 +114,7 @@ public class SudokuKeyboardLayout extends LinearLayout implements IHighlightChan
                 } else {
                     p = new LayoutParams(LayoutParams.MATCH_PARENT, 0, 1);
                 }
-                p.setMargins(5,5,5,5);
+                p.setMargins((int) buttonMargin, (int) buttonMargin, (int) buttonMargin, (int) buttonMargin);
                 buttons[buttonIndex].setLayoutParams(p);
                 /* removed GridLayout because of bad scaling will use now a Linearlayout
                 Spec rowSpec = spec(k,1);

app/src/main/java/org/secuso/privacyfriendlysudoku/ui/view/SudokuSpecialButtonLayout.java

@@ -23,6 +23,7 @@ import android.app.DialogFragment;
 import android.app.FragmentManager;
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.drawable.Drawable;
@@ -59,6 +60,7 @@ public class SudokuSpecialButtonLayout extends LinearLayout implements IHighligh
     Canvas canvas;
     FragmentManager fragmentManager;
     Context context;
+    float buttonMargin;
 
     OnClickListener listener = new OnClickListener() {
         @Override
@@ -111,6 +113,11 @@ public class SudokuSpecialButtonLayout extends LinearLayout implements IHighligh
 
     public SudokuSpecialButtonLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
+
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SudokuSpecialButtonLayout);
+        buttonMargin = a.getDimension(R.styleable.SudokuSpecialButtonLayout_sudokuSpecialKeyboardMargin, 5f);
+        a.recycle();
+
         setWeightSum(fixedButtonsCount);
         this.context = context;
     }
@@ -140,8 +147,8 @@ public class SudokuSpecialButtonLayout extends LinearLayout implements IHighligh
             } else {
                 p = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, 0, 1);
             }
-            fixedButtons[i].setPadding(25, 0, 25, 0);
+            fixedButtons[i].setPadding((int)buttonMargin*5, 0, (int)buttonMargin*5, 0);
-            p.setMargins(5, 5, 5, 5);
+            p.setMargins((int)buttonMargin, (int)buttonMargin, (int)buttonMargin, (int)buttonMargin);
 
             //int width2 =width/(fixedButtonsCount);
             //p.width= width2-15;

app/src/main/res/drawable-hdpi/numpad_highlighted.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <gradient
+        android:endColor="@color/lightblue"
+        android:startColor="@color/lightblue" />
+    <corners android:radius="6dp" />
+    <stroke
+        android:width="10px"
+        android:color="@color/colorPrimaryDark" />
+</shape>

app/src/main/res/drawable-hdpi/numpad_highlighted_four.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <gradient
+        android:endColor="@color/lightblue"
+        android:startColor="@color/lightblue" />
+    <corners android:radius="6dp" />
+    <stroke
+        android:width="10px"
+        android:color="@color/black" />
+</shape>

app/src/main/res/drawable-hdpi/numpad_highlighted_three.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <gradient
+        android:endColor="@color/lightblue"
+        android:startColor="@color/lightblue" />
+    <corners android:radius="6dp" />
+    <stroke
+        android:width="10px"
+        android:color="@color/yellow" />
+</shape>

app/src/main/res/drawable-hdpi/numpad_selected_complete.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <gradient
+        android:endColor="@color/green"
+        android:startColor="@color/green" />
+    <corners android:radius="6dp" />
+    <stroke
+        android:width="10px"
+        android:color="@color/yellow" />
+</shape>

app/src/main/res/drawable-night-hdpi/numpad_highlighted_four.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <gradient
+        android:endColor="@color/lightblue"
+        android:startColor="@color/lightblue" />
+    <corners android:radius="6dp" />
+    <stroke
+        android:width="10px"
+        android:color="@color/white" />
+</shape>

app/src/main/res/drawable-night-v21/numpad_highlighted_four.xml

@@ -6,6 +6,6 @@
         android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="?attr/sudokuButtonBorderWidth"
         android:color="?attr/standardVectorGraphic" />
 </shape>

app/src/main/res/drawable-v21/numpad_highlighted.xml

@@ -6,6 +6,6 @@
         android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="?attr/sudokuButtonBorderWidth"
         android:color="?attr/colorPrimaryDark" />
 </shape>

app/src/main/res/drawable-v21/numpad_highlighted_four.xml

@@ -6,6 +6,6 @@
         android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="?attr/sudokuButtonBorderWidth"
         android:color="?attr/standardVectorGraphic" />
 </shape>

app/src/main/res/drawable-v21/numpad_highlighted_three.xml

@@ -6,6 +6,6 @@
         android:startColor="?attr/activeButtonColor" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="?attr/sudokuButtonBorderWidth"
         android:color="?attr/highlightedButtonBorder" />
 </shape>

app/src/main/res/drawable-v21/numpad_selected_complete.xml

@@ -6,6 +6,6 @@
         android:startColor="?attr/completedButtonColor" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="?attr/sudokuButtonBorderWidth"
         android:color="?attr/completedButtonBorder" />
 </shape>

app/src/main/res/drawable/numpad_highlighted.xml

@@ -6,6 +6,6 @@
         android:startColor="@color/lightblue" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="2px"
         android:color="@color/colorPrimaryDark" />
 </shape>

app/src/main/res/drawable/numpad_highlighted_four.xml

@@ -6,6 +6,6 @@
         android:startColor="@color/lightblue" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="2px"
         android:color="@color/black" />
 </shape>

app/src/main/res/drawable/numpad_highlighted_three.xml

@@ -6,6 +6,6 @@
         android:startColor="@color/lightblue" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="2px"
         android:color="@color/yellow" />
 </shape>

app/src/main/res/drawable/numpad_selected_complete.xml

@@ -6,6 +6,6 @@
         android:startColor="@color/green" />
     <corners android:radius="6dp" />
     <stroke
-        android:width="10px"
+        android:width="2px"
         android:color="@color/yellow" />
 </shape>

app/src/main/res/drawable/numpad_unselected_complete.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
-    <gradient android:endColor="@color/darkyellow" android:startColor="@color/darkyellow" />
+    <gradient android:endColor="@color/green" android:startColor="@color/green" />
     <corners android:radius="6dp" />
 </shape>

app/src/main/res/layout-hdpi/content_game_view.xml

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:id="@+id/main_content"
+    android:layout_marginTop="?android:actionBarSize"
+    android:paddingLeft="@dimen/activity_horizontal_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
+    android:paddingTop="@dimen/activity_vertical_margin"
+    android:paddingBottom="@dimen/activity_vertical_margin"
+    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity">
+
+    <org.secuso.privacyfriendlysudoku.ui.view.SudokuFieldLayout
+        android:id="@+id/sudokuLayout"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:layout_marginBottom="8dp"
+        android:clickable="true"
+        android:focusable="true"
+        android:gravity="center"
+        app:layout_constraintBottom_toTopOf="@+id/sudokuButtonLayout"
+        app:layout_constraintDimensionRatio="1:1"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <LinearLayout
+        android:id="@+id/sudokuButtonLayout"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:minHeight="200dp"
+        android:orientation="vertical"
+        android:weightSum="3"
+        app:layout_constraintTop_toBottomOf="@id/sudokuLayout"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent">
+
+        <org.secuso.privacyfriendlysudoku.ui.view.SudokuKeyboardLayout
+            android:id="@+id/sudokuKeyboardLayout"
+            android:layout_width="fill_parent"
+            android:layout_height="0px"
+            android:layout_weight="2"
+            android:orientation="vertical"
+            android:weightSum="2" />
+
+        <org.secuso.privacyfriendlysudoku.ui.view.SudokuSpecialButtonLayout
+            android:id="@+id/sudokuSpecialLayout"
+            android:layout_width="fill_parent"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            android:weightSum="1" />
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout-hdpi/content_game_view_create_sudoku.xml

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:id="@+id/main_content"
+    android:layout_marginTop="?android:actionBarSize"
+    android:paddingLeft="@dimen/activity_horizontal_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
+    android:paddingTop="@dimen/activity_vertical_margin"
+    android:paddingBottom="@dimen/activity_vertical_margin"
+    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity">
+
+    <org.secuso.privacyfriendlysudoku.ui.view.SudokuFieldLayout
+        android:id="@+id/sudokuLayout"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:layout_marginBottom="8dp"
+        android:clickable="true"
+        android:focusable="true"
+        android:gravity="center"
+        app:layout_constraintBottom_toTopOf="@+id/sudokuButtonLayout"
+        app:layout_constraintDimensionRatio="1:1"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <LinearLayout
+        android:id="@+id/sudokuButtonLayout"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:minHeight="200dp"
+        android:orientation="vertical"
+        android:weightSum="3"
+        app:layout_constraintTop_toBottomOf="@id/sudokuLayout"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent">
+
+        <org.secuso.privacyfriendlysudoku.ui.view.SudokuKeyboardLayout
+            android:id="@+id/sudokuKeyboardLayout"
+            android:layout_width="fill_parent"
+            android:layout_height="0px"
+            android:layout_weight="2"
+            android:orientation="vertical"
+            android:weightSum="2" />
+
+        <org.secuso.privacyfriendlysudoku.ui.view.CreateSudokuSpecialButtonLayout
+            android:id="@+id/createSudokuLayout"
+            android:layout_width="fill_parent"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            android:weightSum="1" />
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/content_game_view.xml

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/main_content"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:id="@+id/main_content"
+    android:layout_marginTop="?actionBarSize"
-    android:layout_marginTop="?android:actionBarSize"
     android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingBottom="@dimen/activity_vertical_margin"
-    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity">
+    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity"
+    tools:layout_editor_absoluteY="56dp">
 
     <org.secuso.privacyfriendlysudoku.ui.view.SudokuFieldLayout
         android:id="@+id/sudokuLayout"
@@ -21,6 +21,7 @@
         android:clickable="true"
         android:focusable="true"
         android:gravity="center"
+        app:layout_constraintVertical_weight="2"
         app:layout_constraintBottom_toTopOf="@+id/sudokuButtonLayout"
         app:layout_constraintDimensionRatio="1:1"
         app:layout_constraintEnd_toEndOf="parent"
@@ -30,14 +31,14 @@
     <LinearLayout
         android:id="@+id/sudokuButtonLayout"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="0dp"
-        android:minHeight="200dp"
         android:orientation="vertical"
         android:weightSum="3"
-        app:layout_constraintTop_toBottomOf="@id/sudokuLayout"
+        app:layout_constraintVertical_weight="1"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent">
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/sudokuLayout">
 
         <org.secuso.privacyfriendlysudoku.ui.view.SudokuKeyboardLayout
             android:id="@+id/sudokuKeyboardLayout"

app/src/main/res/layout/content_game_view_create_sudoku.xml

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/main_content"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:id="@+id/main_content"
+    android:layout_marginTop="?actionBarSize"
-    android:layout_marginTop="?android:actionBarSize"
     android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingBottom="@dimen/activity_vertical_margin"
-    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity">
+    tools:context="org.secuso.privacyfriendlysudoku.ui.GameActivity"
+    tools:layout_editor_absoluteY="56dp">
 
     <org.secuso.privacyfriendlysudoku.ui.view.SudokuFieldLayout
         android:id="@+id/sudokuLayout"
@@ -21,6 +21,7 @@
         android:clickable="true"
         android:focusable="true"
         android:gravity="center"
+        app:layout_constraintVertical_weight="2"
         app:layout_constraintBottom_toTopOf="@+id/sudokuButtonLayout"
         app:layout_constraintDimensionRatio="1:1"
         app:layout_constraintEnd_toEndOf="parent"
@@ -30,14 +31,14 @@
     <LinearLayout
         android:id="@+id/sudokuButtonLayout"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="0dp"
-        android:minHeight="200dp"
         android:orientation="vertical"
         android:weightSum="3"
-        app:layout_constraintTop_toBottomOf="@id/sudokuLayout"
+        app:layout_constraintVertical_weight="1"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent">
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/sudokuLayout">
 
         <org.secuso.privacyfriendlysudoku.ui.view.SudokuKeyboardLayout
             android:id="@+id/sudokuKeyboardLayout"

app/src/main/res/values-hdpi/styles.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+
+    <style name="AppTheme" parent="BaseAppTheme">
+        <item name="sudokuKeyboardMargin">2dp</item>
+        <item name="sudokuKeyboardTextSize">20sp</item>
+        <item name="sudokuSpecialKeyboardMargin">2dp</item>
+        <item name="createSudokuSpecialKeyboardMargin">2dp</item>
+        <item name="sudokuButtonBorderWidth">10px</item>
+    </style>
+
+</resources>
+
+
+

app/src/main/res/values-night/styles.xml

@@ -1,7 +1,7 @@
 <resources>
 
     <!-- Base application theme. -->
-    <style name="AppTheme" parent="Theme.AppCompat.DayNight">
+    <style name="BaseAppTheme" parent="Theme.AppCompat.DayNight">
         <!-- Customize your theme here. -->
         <item name="colorPrimary">@color/colorPrimaryDark</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
@@ -43,6 +43,10 @@
         <item name="sudokuCellTextColor">@color/white</item>
     </style>
 
+    <style name="AppTheme" parent="BaseAppTheme">
+
+    </style>
+
     <style name="ToolbarStyle" parent="Widget.AppCompat.ActionBar">
         <item name="android:textColorPrimary">@color/white</item>
         <item name="colorControlNormal">@color/white</item>

app/src/main/res/values/attrs.xml

@@ -20,6 +20,7 @@
         <attr name="backgroundTutorialSlide" format="color"/>
         <attr name="backgroundTutorialStars" format="color"/>
         <attr name="blueHighlight" format="color"/>
+        <attr name="sudokuButtonBorderWidth" format="dimension"/>
     </declare-styleable>
 
     <declare-styleable name="SudokuCellView">
@@ -38,4 +39,17 @@
         <attr name="sudokuFieldSectionLineColor" format="color" />
         <attr name="sudokuFieldErrorColor" format="color" />
     </declare-styleable>
+
+    <declare-styleable name="SudokuKeyboardLayout">
+        <attr name="sudokuKeyboardMargin" format="dimension" />
+        <attr name="sudokuKeyboardTextSize" format="dimension" />
+    </declare-styleable>
+
+    <declare-styleable name="SudokuSpecialButtonLayout">
+        <attr name="sudokuSpecialKeyboardMargin" format="dimension" />
+    </declare-styleable>
+
+    <declare-styleable name="CreateSudokuSpecialButtonLayout">
+        <attr name="createSudokuSpecialKeyboardMargin" format="dimension" />
+    </declare-styleable>
 </resources>

app/src/main/res/values/styles.xml

@@ -1,7 +1,7 @@
 <resources>
 
     <!-- Base application theme. -->
-    <style name="AppTheme" parent="Theme.AppCompat.DayNight">
+    <style name="BaseAppTheme" parent="Theme.AppCompat.DayNight">
         <!-- Customize your theme here. -->
         <item name="colorPrimary">@color/colorPrimaryDark</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
@@ -43,6 +43,14 @@
         <item name="sudokuCellTextColor">@color/black</item>
     </style>
 
+    <style name="AppTheme" parent="BaseAppTheme">
+        <item name="sudokuKeyboardMargin">1dp</item>
+        <item name="sudokuKeyboardTextSize">10sp</item>
+        <item name="sudokuSpecialKeyboardMargin">1dp</item>
+        <item name="createSudokuSpecialKeyboardMargin">1dp</item>
+        <item name="sudokuButtonBorderWidth">2px</item>
+    </style>
+
     <style name="ToolbarStyle" parent="Widget.AppCompat.ActionBar">
         <item name="android:textColorPrimary">@color/white</item>
         <item name="colorControlNormal">@color/white</item>