如何在 font_family.xml 中使用属性 android:fontStyle="bold" 设置自定义字体

Question

I want to add custom bold font in my font_family.xml . I did not find bold fontStyle="bold" in font family developer doc . It only have normal or italic attribute. Here is font_family.xml

<?xml version="1.0" encoding="utf-8"?>
<font-family xmlns:android="http://schemas.android.com/apk/res/android">
    <font
        android:fontStyle="normal"
        android:fontWeight="400"
        android:font="@font/lobster_regular" />
    <font
        android:fontStyle="italic"
        android:fontWeight="400"
        android:font="@font/lobster_italic" />
</font-family>

So i have to use style like

<style name="fontBoldStyle" parent="@android:style/TextAppearance.Small">
    <item name="android:fontFamily">@font/montserrat_semi_bold</item>
</style>

or like this

<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="@font/montserrat_semi_bold"/>

My question

1. What does fontStyle attribute do? Even i did not provide italic font to font_family.xml , and set textStyle="italic" then my font is italic.
2. how to add custom bold font in font family and set android:fontStyle="bold" in font_family.xml so i dont have to create different styles and i just have to set textStyle="bold"

So what is a solution that i can set 3 of my fonts - normal, bold, italic to font_family.xml, and set android:fontFamily="@font/font_family" on TextView and then i can use android:textStyle="bold" or italic, or normal?

Answer 1

For your 2nd question :

You can add a custom bold font in a font-family , by defining a font with fontWeight="700" :

<font-family xmlns:android="http://schemas.android.com/apk/res/android">
    <font
        android:fontStyle="normal"
        android:fontWeight="400"
        android:font="@font/lobster_regular" />
    <font
        android:fontStyle="italic"
        android:fontWeight="400"
        android:font="@font/lobster_italic" />
    <font
        android:fontStyle="normal"
        android:fontWeight="700"
        android:font="@font/montserrat_semi_bold" />
</font-family>

If a TextView uses this font-family with textStyle="bold" , it will show up in montserrat_semi_bold

Answer 2

There is a way you can do this by applying property called android:textStyle in your layout.xml you can do this:

<TextView 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textStyle="bold" />

Answer 3

Setting font bold programatically this way

mTextView.setTypeface(Typeface.ttf, Typeface.BOLD);

Or

mTextView.setTypeface(mTextView.getTypeface(), Typeface.BOLD);

or You can use paint object and set it to text