custom fonts support The Android Way (#24595)

Summary:
In https://github.com/facebook/react-native/pull/23865, RN introduced support for custom fonts the Android Way. But it introduced performance regression because it'll lookup for a font using getIdentifier() every time fontFamily changed. This PR fixes regression by requiring custom fonts to be listed in **fonts** array, and populating **mTypeCache** at first use using the list.

[Android] [Changed] - Require custom fonts to list in **fonts** array. Fixes performance regression.
Pull Request resolved: https://github.com/facebook/react-native/pull/24595

Reviewed By: mdvacca

Differential Revision: D15184590

Pulled By: fkgozali

fbshipit-source-id: e3feb2396609583ebc95101130186a1f5af931da

ReactAndroid/src/main/java/com/facebook/react/views/text/CustomStyleSpan.java

@@ -7,14 +7,15 @@
 
 package com.facebook.react.views.text;
 
-import javax.annotation.Nullable;
-
 import android.content.res.AssetManager;
 import android.graphics.Paint;
 import android.graphics.Typeface;
 import android.text.TextPaint;
 import android.text.style.MetricAffectingSpan;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 public class CustomStyleSpan extends MetricAffectingSpan implements ReactSpan {
 
   /**
@@ -39,7 +40,7 @@ public class CustomStyleSpan extends MetricAffectingSpan implements ReactSpan {
       int fontStyle,
       int fontWeight,
       @Nullable String fontFamily,
-      AssetManager assetManager) {
+      @NonNull AssetManager assetManager) {
     mStyle = fontStyle;
     mWeight = fontWeight;
     mFontFamily = fontFamily;
@@ -52,7 +53,7 @@ public class CustomStyleSpan extends MetricAffectingSpan implements ReactSpan {
   }
 
   @Override
-  public void updateMeasureState(TextPaint paint) {
+  public void updateMeasureState(@NonNull TextPaint paint) {
     apply(paint, mStyle, mWeight, mFontFamily, mAssetManager);
   }
 
@@ -116,5 +117,4 @@ public class CustomStyleSpan extends MetricAffectingSpan implements ReactSpan {
     }
     paint.setSubpixelText(true);
   }
-
 }

ReactAndroid/src/main/java/com/facebook/react/views/text/ReactFontManager.java

@@ -7,15 +7,18 @@
 
 package com.facebook.react.views.text;
 
-import javax.annotation.Nullable;
-
 import java.util.HashMap;
 import java.util.Map;
 
+import android.content.Context;
 import android.content.res.AssetManager;
 import android.graphics.Typeface;
 import android.util.SparseArray;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.res.ResourcesCompat;
+
 /**
  * Class responsible to load and cache Typeface objects. It will first try to load typefaces inside
  * the assets/fonts folder and if it doesn't find the right Typeface in that folder will fall back
@@ -36,10 +39,12 @@ public class ReactFontManager {
 
   private static ReactFontManager sReactFontManagerInstance;
 
-  private Map<String, FontFamily> mFontCache;
+  final private Map<String, FontFamily> mFontCache;
+  final private Map<String, Typeface> mCustomTypefaceCache;
 
   private ReactFontManager() {
     mFontCache = new HashMap<>();
+    mCustomTypefaceCache = new HashMap<>();
   }
 
   public static ReactFontManager getInstance() {
@@ -49,8 +54,7 @@ public class ReactFontManager {
     return sReactFontManagerInstance;
   }
 
-  public
-  @Nullable Typeface getTypeface(
+  public @Nullable Typeface getTypeface(
       String fontFamilyName,
       int style,
       AssetManager assetManager) {
@@ -60,6 +64,13 @@ public class ReactFontManager {
       mFontCache.put(fontFamilyName, fontFamily);
     }
 
+    if(mCustomTypefaceCache.containsKey(fontFamilyName)) {
+      return Typeface.create(
+        mCustomTypefaceCache.get(fontFamilyName),
+        style
+      );
+    }
+
     Typeface typeface = fontFamily.getTypeface(style);
     if (typeface == null) {
       typeface = createTypeface(fontFamilyName, style, assetManager);
@@ -71,6 +82,20 @@ public class ReactFontManager {
     return typeface;
   }
 
+  /*
+   * This method allows you to load custom fonts from res/font folder as provided font family name.
+   * Fonts may be one of .ttf, .otf or XML (https://developer.android.com/guide/topics/ui/look-and-feel/fonts-in-xml).
+   * To support multiple font styles or weights, you must provide a font in XML format.
+   *
+   * ReactFontManager.getInstance().addCustomFont(this, "Srisakdi", R.font.srisakdi);
+   */
+  public void addCustomFont(@NonNull Context context, @NonNull String fontFamily, int fontId) {
+    Typeface font = ResourcesCompat.getFont(context, fontId);
+    if (font != null) {
+      mCustomTypefaceCache.put(fontFamily, font);
+    }
+  }
+
   /**
    * Add additional font family, or replace the exist one in the font memory cache.
    * @param style