绑定不会更新TabLayout自定义标题视图

<android.support.design.widget.TabLayout
    android:id="@+id/tabLayout"
    ... />

<android.support.v4.view.ViewPager
    android:id="@+id/viewPager"
    ... />

TabLayout tabLayout = findViewById(R.id.tabLayout);
ViewPager viewPager = findViewById(R.id.viewPager);

viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);

private class CustomTabView extends TabLayout.TabView {
    private TextView titleTextView;

    public CustomTabView(Context context) {
        super(context);
        // 初始化自定义的标题视图
        View view = LayoutInflater.from(context).inflate(R.layout.custom_tab_view, this, true);
        titleTextView = view.findViewById(R.id.titleTextView);
    }

    @Override
    public void update() {
        super.update();
        // 更新标题视图
        titleTextView.setText(getText());
    }
}

TabLayout.Tab tab1 = tabLayout.newTab();
tab1.setCustomView(new CustomTabView(this));
tab1.setText("Tab 1");

TabLayout.Tab tab2 = tabLayout.newTab();
tab2.setCustomView(new CustomTabView(this));
tab2.setText("Tab 2");

tabLayout.addTab(tab1);
tabLayout.addTab(tab2);