Android支持库-从NavigationView获取标题TextView

Question

Is it possible to get a TextView for the title of a MenuItem for a NavigationView ? (I want to change the font)

drawer_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto">

    <group android:checkableBehavior="single">

        <item
        android:id="@+id/cards"
        android:icon="@drawable/ic_menu_cards"
        android:clickable="false"
        android:title="Cards"
        app:showAsAction="always"/>

        <item
        android:id="@+id/waiter"
        android:icon="@drawable/ic_menu_waiter"
        android:clickable="false"
        android:title="Timer Mode"
        app:showAsAction="always"/>

        <item
        android:id="@+id/settings"
        android:icon="@drawable/ic_menu_settings"
        android:title="Settings"
        app:showAsAction="always"/>


        <item
        android:id="@+id/purchase"
        android:icon="@drawable/ic_menu_purchase"
        android:clickable="false"
        android:title="Purchase"
        app:showAsAction="always"/>

        <item
        android:id="@+id/feedback"
        android:icon="@drawable/ic_menu_feedback"
        android:clickable="false"
        android:title="Feedback"
        app:showAsAction="always"/>
    </group>
</menu>

And my layout:

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <!-- Removed for simplicity -->

    </LinearLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/navigation_view"
        android:layout_height="match_parent"
        android:layout_width="wrap_content"
        android:layout_gravity="start"
        android:theme="@style/NavigationDrawer"
        app:headerLayout="@layout/navigation_view_header"
        app:itemTextColor="@color/white"
        app:menu="@menu/drawer_menu" />

</android.support.v4.widget.DrawerLayout>

I have seen some other example where casting the MenuItem to TextView should work but in my case it just returns null.

TextView title = (TextView) navigationView.getMenu().getItem(0) <-- TextView becomes null

How can I access the title so I can manipulate the font?

More Background info:

I am usually setting the font using DataBindings but for Android Support Library components this does not work so I have to access the TextView manually and set it like this:

textView.setTypeface(FontCache.getInstance(textView.getContext()).get("lato_regular"));

Answer 1

I finally found a way to do it. Its not very pretty but It works.

Pass MenuItems to a method:

setMenuItemFont(binding.navigationView.getMenu().getItem(0));

Method looks like this:

private void setMenuItemFont(MenuItem menuItem) {
    SpannableString span = new SpannableString(menuItem.getTitle());
    span.setSpan(new CustomTypefaceSpan(FontCache.getInstance(getApplicationContext()).get("lato_regular")), 0 , span.length(),  Spannable.SPAN_INCLUSIVE_INCLUSIVE);
    menuItem.setTitle(span);
}

Helper class that extends a TypefaceSpan:

package android.app.app;

import android.graphics.Typeface;
import android.text.TextPaint;
import android.text.style.TypefaceSpan;

public class CustomTypefaceSpan extends TypefaceSpan {

    private final Typeface newType;

    public CustomTypefaceSpan(Typeface type) {
        super("");
        newType = type;
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        ds.setTypeface(newType);
    }

    @Override
    public void updateMeasureState(TextPaint paint) {
        paint.setTypeface(newType);
    }
}