EmojiCompat.GlyphChecker

public interface EmojiCompat.GlyphChecker


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

Summary

Public methods

abstract boolean
hasGlyph(
    @NonNull CharSequence charSequence,
    @IntRange(from = 0) int start,
    @IntRange(from = 0) int end,
    @IntRange(from = 0) int sdkAdded
)

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

Added in 1.0.0
abstract boolean hasGlyph(
    @NonNull CharSequence charSequence,
    @IntRange(from = 0) int start,
    @IntRange(from = 0) int end,
    @IntRange(from = 0) int sdkAdded
)

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 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 hasGlyph 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 sdkAddedinformation, and some predefined OEMs, it is possible to write the following code snippet.
static class MyGlyphChecker implements EmojiCompat.GlyphChecker {
    private TextPaint mTextPaint = new TextPaint();

    @Override
    public boolean hasGlyph(@NonNull CharSequence charSequence, int start, int end,
            int sdkAdded) {
        if (isOnDeviceX()) {
            // if on this specific device we only rely on sdkAdded
            return sdkAdded < Build.VERSION.SDK_INT;
        } else {
            String string = createString(charSequence, start, end);
            return PaintCompat.hasGlyph(mTextPaint, string);
        }
    }

}
Parameters
@NonNull CharSequence charSequence

the CharSequence that is being processed

@IntRange(from = 0) int start

the inclusive starting offset for the emoji in the charSequence

@IntRange(from = 0) int end

the exclusive end offset for the emoji in the charSequence

@IntRange(from = 0) int sdkAdded

the API version that the emoji was added in AOSP

Returns
boolean

true if the given sequence can be rendered as a single glyph, otherwise false.