How to set the font in application level for entire application

SetFontAtApplicationLevel

Yes with reflection. This works ([based on this answer](http://stackoverflow.com/a/16275257/360211)):

    import java.lang.reflect.Field;
    import android.content.Context;
    import android.graphics.Typeface;

    public final class FontsOverride {

    	public static void setDefaultFont(Context context,
    			String staticTypefaceFieldName, String fontAssetName) {
    		final Typeface regular = Typeface.createFromAsset(context.getAssets(),
    				fontAssetName);
    		replaceFont(staticTypefaceFieldName, regular);
    	}
    
    	protected static void replaceFont(String staticTypefaceFieldName,
    			final Typeface newTypeface) {
    		try {
    			final Field staticField = Typeface.class
    					.getDeclaredField(staticTypefaceFieldName);
    			staticField.setAccessible(true);
    			staticField.set(null, newTypeface);
    		} catch (NoSuchFieldException e) {
    			e.printStackTrace();
    		} catch (IllegalAccessException e) {
    			e.printStackTrace();
    		}
    	}
    }

You then need to overload the few default fonts, for example in an [application](http://developer.android.com/reference/android/app/Application.html) class:

    public final class Application extends android.app.Application {
    	@Override
    	public void onCreate() {
    		super.onCreate();
            FontsOverride.setDefaultFont(this, "DEFAULT", "MyFontAsset.ttf");
            FontsOverride.setDefaultFont(this, "MONOSPACE", "MyFontAsset2.ttf");
            FontsOverride.setDefaultFont(this, "SERIF", "MyFontAsset3.ttf");
            FontsOverride.setDefaultFont(this, "SANS_SERIF", "MyFontAsset4.ttf");
        }
    }

Or course if you are using the same font file, you can improve on this to load it just once.

However I tend to just override one, say `"MONOSPACE"`, then set up a style to force that font typeface application wide:

    <resources>
        <style name="AppBaseTheme" parent="android:Theme.Light">
        </style>
    
        <!-- Application theme. -->
        <style name="AppTheme" parent="AppBaseTheme">
            <item name="android:typeface">monospace</item>
        </style>
    </resources>

API 21 Android 5.0
==

I've investigated the reports in the comments that it doesn't work and it appears to be incompatible with the theme `android:Theme.Material.Light`.

If that theme is not important to you, use an older theme, e.g.:

    <style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar">
        <item name="android:typeface">monospace</item>
    </style>

Resource: http://stackoverflow.com/a/16883281/1083093