最近开发的一款产品，不同的内容、模块使用了很多种字体。我在application里面设置了一种全局的字体，在普通的textView都已生效，但是在tabLayout里面却未生效，以下方法可以修改tabLayout 里面的字体：

//更改字体
public void changeTabsFont(XTabLayout tabLayout) {
    ViewGroup vg = (ViewGroup) tabLayout.getChildAt(0);
    int tabsCount = vg.getChildCount();
    for (int j = 0; j < tabsCount; j++) {
        ViewGroup vgTab = (ViewGroup) vg.getChildAt(j);
        int tabChildsCount = vgTab.getChildCount();
        for (int i = 0; i < tabChildsCount; i++) {
            View tabViewChild = vgTab.getChildAt(i);
            if (tabViewChild instanceof TextView) {
                ((TextView) tabViewChild).setTypeface(TypefaceCache.getInstance(mContext).get("HarmonyOS_Sans_SC_Regular.ttf"));
            }
        }
    }
}

以下是我自己的TypefaceCache类，可直接使用：

public class TypefaceCache {
    private static TypefaceCache sInstance;

    private final Hashtable<String, Typeface> mCache = new Hashtable<String, Typeface>();

    private final Application mApplication;

    private TypefaceCache(Application application) {
        mApplication = application;
    }

    /**
     * If the cache has an instance for the typeface name, this will return the instance immediately.
     * Otherwise this method will create typeface instance and put it into the cache and return the instance.
     *
     * @param name the typeface name.
     * @return {@link Typeface} instance.
     */
    public synchronized Typeface get(String name) {
        Typeface typeface = mCache.get(name);
        if (typeface == null) {
            try {
                typeface = Typeface.createFromAsset(mApplication.getAssets(), name);
            } catch (Exception exp) {
                return null;
            }
            mCache.put(name, typeface);
        }
        return typeface;
    }

    /**
     * Retrieve this cache.
     *
     * @param context the context.
     * @return the cache instance.
     */
    public static synchronized TypefaceCache getInstance(Context context) {
        if (sInstance == null) {
            sInstance = new TypefaceCache((Application) context.getApplicationContext());
        }
        return sInstance;
    }
}

PS：使用此方法，在初始化的时候的确可以达到修改字体的目的，但是在切换viewPager的时候又恢复到了默认的字体，所以我又在在viewPager的addOnPageChangeListener()里面又调用了一次，每次切换的时候重新设置，就解决了此问题