Prevent custom system fonts overriding app fonts

Question

Devices like Samsung allows users to set custom system fonts. Issue is that those fonts can be overriding my app fonts. I mean if I set Arial font in my app and I've set Calibri font as system font on my mobile then Arial will be overridden by the Calibri font.

How to prevent this situation?

Answer 1

• "If you need to set one font for all TextView's in your Android application you can use this solution.

• It will override ALL TextView's typefaces, including the Action Bar, custom system fonts and other standard components, but EditText's password font won't be overridden." (For obvious reasons).

• Using reflection to override default typeface and the Application class.

• NOTE: DO NOT FORGET TO SET TYPEFACE FOR APP THEME AS DEFAULT TYPEFACE WHICH WILL BE OVERRIDDEN

MyApp.java:

public class MyApp extends Application {

  @Override
  public void onCreate() {
    TypefaceUtil.overrideFont(getApplicationContext(), "SERIF", "fonts/Roboto-Regular.ttf"); // font from assets: "assets/fonts/Roboto-Regular.ttf
  }
}

res/themes.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <style name="MyAppTheme" parent="@android:style/Theme.Holo.Light">
    <!-- you should set typeface which you want to override with TypefaceUtil -->
    <item name="android:typeface">serif</item>
  </style>
</resources>

TypefaceUtil.java:

import android.content.Context;
import android.graphics.Typeface;
import android.util.Log;

import java.lang.reflect.Field;

public class TypefaceUtil {

    /**
     * Using reflection to override default typeface
     * NOTICE: DO NOT FORGET TO SET TYPEFACE FOR APP THEME AS DEFAULT TYPEFACE WHICH WILL BE OVERRIDDEN
     * @param context to work with assets
     * @param defaultFontNameToOverride for example "monospace"
     * @param customFontFileNameInAssets file name of the font from assets
     */
    public static void overrideFont(Context context, String defaultFontNameToOverride, String customFontFileNameInAssets) {
        try {
            final Typeface customFontTypeface = Typeface.createFromAsset(context.getAssets(), customFontFileNameInAssets);

            final Field defaultFontTypefaceField = Typeface.class.getDeclaredField(defaultFontNameToOverride);
            defaultFontTypefaceField.setAccessible(true);
            defaultFontTypefaceField.set(null, customFontTypeface);
        } catch (Exception e) {
            Log.e("Can not set custom font " + customFontFileNameInAssets + " instead of " + defaultFontNameToOverride);
        }
    }
}

assets/fonts/Roboto-Regular.ttf:

Put your font here e.g. Arial.

ref1

Author Artem Zinnatullin