Is it possible to set a custom font for entire of application?

Question

I need to use certain font for my entire application. I have .ttf file for the same. Is it possible to set this as default font, at application start up and then use it else

Answer 1

A brilliant solution can be found here: https://coderwall.com/p/qxxmaa/android-use-a-custom-font-everywhere.

Simply extend activities from BaseActivity and write those methods. Also you should better cache fonts as described here: https://stackoverflow.com/a/16902532/2914140.

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After some research I wrote code that works at Samsung Galaxy Tab A (Android 5.0). Used code of weston and Roger Huang as well as https://stackoverflow.com/a/33236102/2914140. Also tested on Lenovo TAB 2 A10-70L, where it doesn't work. I inserted a font 'Comic Sans' here in order to see a difference.

import android.content.Context;
import android.graphics.Typeface;
import android.os.Build;
import android.util.Log;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

public class FontsOverride {
    private static final int BOLD = 1;
    private static final int BOLD_ITALIC = 2;
    private static final int ITALIC = 3;
    private static final int LIGHT = 4;
    private static final int CONDENSED = 5;
    private static final int THIN = 6;
    private static final int MEDIUM = 7;
    private static final int REGULAR = 8;

    private Context context;

    public FontsOverride(Context context) {
        this.context = context;
    }

    public void loadFonts() {
        Map fontsMap = new HashMap<>();
        fontsMap.put("sans-serif", getTypeface("comic.ttf", REGULAR));
        fontsMap.put("sans-serif-bold", getTypeface("comic.ttf", BOLD));
        fontsMap.put("sans-serif-italic", getTypeface("comic.ttf", ITALIC));
        fontsMap.put("sans-serif-light", getTypeface("comic.ttf", LIGHT));
        fontsMap.put("sans-serif-condensed", getTypeface("comic.ttf", CONDENSED));
        fontsMap.put("sans-serif-thin", getTypeface("comic.ttf", THIN));
        fontsMap.put("sans-serif-medium", getTypeface("comic.ttf", MEDIUM));
        overrideFonts(fontsMap);
    }

    private void overrideFonts(Map typefaces) {
        if (Build.VERSION.SDK_INT == 21) {
            try {
                final Field field = Typeface.class.getDeclaredField("sSystemFontMap");
                field.setAccessible(true);
                Map oldFonts = (Map) field.get(null);
                if (oldFonts != null) {
                    oldFonts.putAll(typefaces);
                } else {
                    oldFonts = typefaces;
                }
                field.set(null, oldFonts);
                field.setAccessible(false);
            } catch (Exception e) {
                Log.e("TypefaceUtil", "Cannot set custom fonts");
            }
        } else {
            try {
                for (Map.Entry entry : typefaces.entrySet()) {
                    final Field staticField = Typeface.class.getDeclaredField(entry.getKey());
                    staticField.setAccessible(true);
                    staticField.set(null, entry.getValue());
                }
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
    }

    private Typeface getTypeface(String fontFileName, int fontType) {
        final Typeface tf = Typeface.createFromAsset(context.getAssets(), "fonts/" + fontFileName);
        return Typeface.create(tf, fontType);
    }
}

To run the code in entire application you should write in some class like Application the following:

    new FontsOverride(this).loadFonts();

Create a folder 'fonts' inside 'assets' and put needed fonts there. A simple instruction may be found here: https://stackoverflow.com/a/31697103/2914140.

The Lenovo device also incorrectly gets a value of a typeface. In most times it returns Typeface.NORMAL, sometimes null. Even if a TextView is bold (in xml-file layout). See here: TextView isBold always returns NORMAL. This way a text on a screen is always in a regural font, not bold or italic. So I think it's a bug of a producer.