Added in API level 29

CustomFallbackBuilder

class CustomFallbackBuilder
kotlin.Any
   ↳ android.graphics.Typeface.CustomFallbackBuilder

A builder class for creating new Typeface instance. There are two font fallback mechanisms, custom font fallback and system font fallback. The custom font fallback is a simple ordered list. The text renderer tries to see if it can render a character with the first font and if that font does not support the character, try next one and so on. It will keep trying until end of the custom fallback chain. The maximum length of the custom fallback chain is 64. The system font fallback is a system pre-defined fallback chain. The system fallback is processed only when no matching font is found in the custom font fallback.

Examples, 1) Create Typeface from single ttf file. 

<code>
  Font font = new Font.Builder("your_font_file.ttf").build();
  FontFamily family = new FontFamily.Builder(font).build();
  Typeface typeface = new Typeface.CustomFallbackBuilder(family).build();
  </code>
 2) Create Typeface from multiple font files and select bold style by default. 
<code>
  Font regularFont = new Font.Builder("regular.ttf").build();
  Font boldFont = new Font.Builder("bold.ttf").build();
  FontFamily family = new FontFamily.Builder(regularFont)
      .addFont(boldFont).build();
  Typeface typeface = new Typeface.CustomFallbackBuilder(family)
      .setWeight(Font.FONT_WEIGHT_BOLD)  // Set bold style as the default style.
                                         // If the font family doesn't have bold style font,
                                         // system will select the closest font.
      .build();
  </code>
 3) Create Typeface from single ttf file and if that font does not have glyph for the characters, use "serif" font family instead. 
<code>
  Font font = new Font.Builder("your_font_file.ttf").build();
  FontFamily family = new FontFamily.Builder(font).build();
  Typeface typeface = new Typeface.CustomFallbackBuilder(family)
      .setSystemFallback("serif")  // Set serif font family as the fallback.
      .build();
  </code>
 4) Create Typeface from single ttf file and set another ttf file for the fallback. 
<code>
  Font font = new Font.Builder("English.ttf").build();
  FontFamily family = new FontFamily.Builder(font).build();
 
  Font fallbackFont = new Font.Builder("Arabic.ttf").build();
  FontFamily fallbackFamily = new FontFamily.Builder(fallbackFont).build();
  Typeface typeface = new Typeface.CustomFallbackBuilder(family)
      .addCustomFallback(fallbackFamily)  // Specify fallback family.
      .setSystemFallback("serif")  // Set serif font family as the fallback.
      .build();
  </code>

Summary

Public constructors

Constructs a builder with a font family.
Public methods
Typeface.CustomFallbackBuilder

Append a font family to the end of the custom font fallback.
Typeface

Create the Typeface based on the configured values.
static Int

Returns the maximum capacity of custom fallback families.
Typeface.CustomFallbackBuilder

Sets a font style of the Typeface.
Typeface.CustomFallbackBuilder

Sets a system fallback by name.

Public constructors

CustomFallbackBuilder

Added in API level 29
CustomFallbackBuilder(family: FontFamily)

Constructs a builder with a font family.

Parameters
family FontFamily: a family object This value cannot be null.

Public methods

addCustomFallback

Added in API level 29
fun addCustomFallback(family: FontFamily): Typeface.CustomFallbackBuilder

Append a font family to the end of the custom font fallback. You can set up to 64 custom fallback families including the first font family you passed to the constructor. For more information about fallback, see class description.

Parameters
family FontFamily: a fallback family This value cannot be null.
Return
Typeface.CustomFallbackBuilder This value cannot be null.
Exceptions
java.lang.IllegalArgumentException if you give more than 64 custom fallback families

build

Added in API level 29
fun build(): Typeface

Create the Typeface based on the configured values.

Return
Typeface the Typeface object This value cannot be null.

getMaxCustomFallbackCount

Added in API level 29
static fun getMaxCustomFallbackCount(): Int

Returns the maximum capacity of custom fallback families. This includes the first font family passed to the constructor. It is guaranteed that the value will be greater than or equal to 64.

Return
Int the maximum number of font families for the custom fallback Value is 64 or greater

setStyle

Added in API level 29
fun setStyle(style: FontStyle): Typeface.CustomFallbackBuilder

Sets a font style of the Typeface. If the font family doesn't have a font of given style, system will select the closest font from font family. For example, if a font family has fonts of 300 weight and 700 weight then setWeight(400) is called, system will select the font of 300 weight.

Parameters
style FontStyle: a font style This value cannot be null.
Return
Typeface.CustomFallbackBuilder This value cannot be null.

setSystemFallback

Added in API level 29
fun setSystemFallback(familyName: String): Typeface.CustomFallbackBuilder

Sets a system fallback by name. You can specify generic font family names or OEM specific family names. If the system don't have a specified fallback, the default fallback is used instead. For more information about generic font families, see CSS specification For more information about fallback, see class description.

Parameters
familyName String: a family name to be used for fallback if the provided fonts can not be used This value cannot be null.
Return
Typeface.CustomFallbackBuilder This value cannot be null.