Added Java native code

Author: kubaflo

src/Controls/src/Core/Platform/Android/Extensions/FormattedStringExtensions.cs

@@ -64,12 +64,8 @@ internal static SpannableString ToSpannableStringNewWay(
 
 			var builder = new StringBuilder();
 
-			var fontMetrics = context?.Resources?.DisplayMetrics != null ? new Paint()
-			{
-				TextSize = TypedValue.ApplyDimension(ComplexUnitType.Sp, (float)defaultFontSize, context.Resources.DisplayMetrics)
-			}.GetFontMetrics()
-			: null;
-			
+			var fontMetrics = PlatformInterop.GetFontMetrics(context, defaultFontSize);
+
 			for (int i = 0; i < formattedString.Spans.Count; i++)
 			{
 				Span span = formattedString.Spans[i];

src/Core/AndroidNative/maui/src/main/java/com/microsoft/maui/PlatformInterop.java

@@ -591,6 +591,26 @@ public static Rect getCurrentWindowMetrics(Activity activity) {
             .getBounds();
     }
 
+    /**
+     * Gets font metrics based on the given context and default font size
+     * @param context
+     * @param defaultFontSize
+     * @return FontMetrics object or null if context or display metrics is null
+     */
+    public static Paint.FontMetrics getFontMetrics(Context context, double defaultFontSize) {
+        if (context != null && context.getResources().getDisplayMetrics() != null) {
+            return new Paint() {{
+                setTextSize(TypedValue.applyDimension(
+                        TypedValue.COMPLEX_UNIT_SP,
+                        (float) defaultFontSize,
+                        context.getResources().getDisplayMetrics()
+                ));
+            }}.getFontMetrics();
+        } else {
+            return null;
+        }
+    }
+
     private static class ColorStates
     {
         static final int[] EMPTY = new int[] { };