How to check whether given text is english or chinese in android?

Question

I am designing one android application in English and Chinese both. I want to know whether the user type English text or Chinese text?. Is there any way to check this in android?

Answer 1

If you want to detect whether the input string contains Chinese-like character(s) (CJK), the following may help you:

public static boolean isCJK(String str){
        int length = str.length();
        for (int i = 0; i < length; i++){
            char ch = str.charAt(i);
            Character.UnicodeBlock block = Character.UnicodeBlock.of(ch);
            if (Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS.equals(block)|| 
                Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS.equals(block)|| 
                Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A.equals(block)){
                return true;
            }
        }
        return false;
    }

Answer 2

The accepted answer is either incomplete or outdated. Here are a few methods you can use to test if a character is a CJK Ideograph. My fuller answer is here.

It is better to use the codepoint rather than charAt (as in the accepted answer) because many Chinese characters are in a higher code plane. Using charAt will just give you one of the surrogate pairs rather than the actual Chinese character. So a better way to loop through a String is like this:

final int length = myString.length();
for (int offset = 0; offset < length; ) {
    final int codepoint = Character.codePointAt(myString, offset);

    // use codepoint here

    offset += Character.charCount(codepoint);
}

And testing the codepoints can be done in one of the following ways.

private boolean isCJK(int codepoint) {
    Character.UnicodeBlock block = Character.UnicodeBlock.of(codepoint);
    return (Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS.equals(block)||
            Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A.equals(block) ||
            Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B.equals(block) ||
            Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_C.equals(block) || // api 19, remove these if supporting lower versions
            Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_D.equals(block) || // api 19
            Character.UnicodeBlock.CJK_COMPATIBILITY.equals(block) ||
            Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS.equals(block) ||
            Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS.equals(block) ||
            Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS_SUPPLEMENT.equals(block) ||
            Character.UnicodeBlock.CJK_RADICALS_SUPPLEMENT.equals(block) ||
            Character.UnicodeBlock.CJK_STROKES.equals(block) ||                        // api 19
            Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION.equals(block) ||
            Character.UnicodeBlock.ENCLOSED_CJK_LETTERS_AND_MONTHS.equals(block) ||
            Character.UnicodeBlock.ENCLOSED_IDEOGRAPHIC_SUPPLEMENT.equals(block) ||    // api 19
            Character.UnicodeBlock.KANGXI_RADICALS.equals(block) ||
            Character.UnicodeBlock.IDEOGRAPHIC_DESCRIPTION_CHARACTERS.equals(block));
}

Or for API 19

private boolean isCJK(int codepoint) {
    return Character.isIdeographic(codepoint);
}

Or for API 24

private boolean isCJK(int codepoint) {
    return (Character.UnicodeScript.of(codepoint) == Character.UnicodeScript.HAN);
}