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GlyphChecker

interface GlyphChecker
androidx.emoji.text.EmojiCompat.GlyphChecker

Interface to check if a given emoji exists on the system.

Summary

Public methods
abstract Boolean
hasGlyph(@NonNull charSequence: CharSequence, @IntRange(0) start: Int, @IntRange(0) end: Int, @IntRange(0) sdkAdded: Int)

Return true if the emoji that is in charSequence between start(inclusive) and end(exclusive) can be rendered on the system using the default Typeface.

Public methods

hasGlyph

abstract fun hasGlyph(
    @NonNull charSequence: CharSequence,
    @IntRange(0) start: Int,
    @IntRange(0) end: Int,
    @IntRange(0) sdkAdded: Int
): Boolean

Return true if the emoji that is in charSequence between start(inclusive) and end(exclusive) can be rendered on the system using the default Typeface.

This function is called after an emoji is identified in the given charSequence and EmojiCompat wants to know if that emoji can be rendered on the system. The result of this call will be cached and the same emoji sequence won't be asked for the same EmojiCompat instance.

When the function returns true, it will mean that the system can render the emoji. In that case if Config#setReplaceAll is set to false, then no EmojiSpan will be added in the final emoji processing result.

When the function returns false, it will mean that the system cannot render the given emoji, therefore an EmojiSpan will be added to the final emoji processing result.

The default implementation of this class uses androidx.core.graphics.PaintCompat#hasGlyph(Paint, String) function to check if the emoji can be rendered on the system. This is required even if EmojiCompat knows about the SDK Version that the emoji was added on AOSP. Just the sdkAdded information is not enough to reliably decide if emoji can be rendered since this information may not be consistent across all the OEMs and all the Android versions.

With this interface you can apply your own heuristics to check if the emoji can be rendered on the system. For example, if you'd like to rely on the sdkAdded information, and some predefined OEMs, it is possible to write the following code snippet.

Parameters
charSequence CharSequence: the CharSequence that is being processed
start Int: the inclusive starting offset for the emoji in the charSequence
end Int: the exclusive end offset for the emoji in the charSequence
sdkAdded Int: the API version that the emoji was added in AOSP
Return
Boolean true if the given sequence can be rendered as a single glyph, otherwise false.