How to detect emoji support on Android by code

问题

By code, I can make a button that inserts these 3 emojis into the text: ⚽️😈🐺

On many phones when the user clicks the button, though, the problem is that ⚽️😈🐺 displays as [X][X][X]. Or even worse, it displays only three empty spaces.

I would like to disable and hide my own built-in emoji-keypad on Android devices that do not display emojis correctly. Does anyone knows or have a tip on how to detect in code if a device has emoji support?

I have read that emoji is supported from android 4.1, but that is not my experience....

回答1:

I just implemented a solution for this problem myself. The nice thing with Android is that it is open source so that when you come around problems like these, there's a good chance you can find an approach to help you.

In the Android Open Source Project, you can find a method where they use Paint.hasGlyph to detect whether a font exists for a given emoji. However, as this method is not available before API 23, they also do test renders and compare the result against the width of 'tofu' (the [x] character you mention in your post.)

There are some other failings with this approach, but it should be enough to get you started.

Google source:

https://android.googlesource.com/platform/packages/inputmethods/LatinIME/+/master/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategory.java#441
https://android.googlesource.com/platform/packages/inputmethods/LatinIME/+/master/java/src/com/android/inputmethod/keyboard/KeyboardLayoutSet.java

回答2:

Based on Jason Gore answer:

For example create boolean canShowFlagEmoji:

 private static boolean canShowFlagEmoji() {
        Paint paint = new Paint();
        String switzerland = "\uD83C\uDDE8\uD83C\uDDED"; //  Here enter Surrogates of Emoji
        try {
            return paint.hasGlyph(switzerland);
        } catch (NoSuchMethodError e) {
            // Compare display width of single-codepoint emoji to width of flag emoji to determine
            // whether flag is rendered as single glyph or two adjacent regional indicator symbols.
            float flagWidth = paint.measureText(switzerland);
            float standardWidth = paint.measureText("\uD83D\uDC27"); //  U+1F427 Penguin
            return flagWidth < standardWidth * 1.25;
            // This assumes that a valid glyph for the flag emoji must be less than 1.25 times
            // the width of the penguin.
        }
    }

And then in code whenever when you need to check if emoji is available:

if (canShowFlagEmoji()){
    // Code when FlagEmoji is available
} else {
    // And when not
}

Surrogates of emoji you can get here, when you click on detail.

回答3:

An alternative option might be to include the Android "Emoji Compatibility" library, which would detect and add any required Emoji characters to apps running on Android 4.4 (API 19) and later: https://developer.android.com/topic/libraries/support-library/preview/emoji-compat.html

来源：https://stackoverflow.com/questions/39194616/how-to-detect-emoji-support-on-android-by-code

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android

emoji

android-api-levels