how to encode and decode emoji in android?

Question

I used https://github.com/rockerhieu/emojicon library in my application. When I pass a static unicode string in my code the emoji is visible but if I send the emoji to php server using regular get webservice and retrive the string then it just showing unicode string into my application. both static and server retrieved strings are same if I compare.

Can anybody tell me what wrong I have done into my application. the same application is developed in IOS and what they did is they first encoding the string into ASCII>UTF-8 while sending to server. then they are decoding the string in same way as they send. Can anybody suggest me IF this would be compatible with android also, If yes then how can I do this.

Answer 1

We can use commons-lang(commons-lang-2.5.jar) library for encoding and decoding of the unicode characters. Download jar file here or use gradle: compile 'org.apache.commons:commons-lang3:3.4'.

For Encoding use - StringEscapeUtils.escapeJava(String text) This can be used in android EditText when call getText method, where it will encode the unicode characters properly before sending to web server.

For Decoding use - StringEscapeUtils.unescapeJava(String text) This can be used in android TextView to setText, where it will decode the unicode characters properly after receiving the response from web server.

Ex:

EditText etEmojiEditText = new EditText(this);
etEmojiEditText.setText("TYPE SOMETHING IN EMOJI");

String toServer = etEmojiEditText.getText();
String toServerUnicodeEncoded = StringEscapeUtils.escapeJava(toServer);

String serverResponse = "SOME RESPONSE FROM SERVER WITH UNICODE CHARACTERS";
String fromServerUnicodeDecoded = StringEscapeUtils.unescapeJava(serverResponse);

FYI Use the encoding and decoding for web service side as well. Unicode encoded string should be decoded from web service and response from web service should be encoded before sending to clients. Server tables should contain utf8mb4 instead of utf8, because unicode character needs 4bytes per character. Therefore unicode will not be represented in 3bytes.

Answer 2

I have used the same library as you for emoji. I have used URLEncoder.encode(commentString, "UTF-8") for encoding and similarly, URLDecoder.decode(encodedComment, "UTF-8") for decoding.

Works perfectly for me. Hopefully for you too.

Answer 3

Emojis needs to be encoded and decoded . You should send the text to server by encoding and show again in the app by decoding the same. The code is below for the encryption and decryption.

public static String encodeEmoji (String message) {
try {
return URLEncoder.encode(message,
"UTF-8");
} catch (UnsupportedEncodingException e) {
return message;
}
}


public static String decodeEmoji (String message) {
String myString= null;
try {
return URLDecoder.decode(
message, "UTF-8");
} catch (UnsupportedEncodingException e) {
return message;
}
} 

Answer 4

I am using the same library ... You don't need to encode or escape the emoji ... simply getText().toString() will work.

Follow the steps

In mysql change the field collation to utf8mb4_unicode_ci (my database and table collation is utf8_unicode_ci)

Used PHP Codigniter on server so the database configuration

'char_set' => 'utf8mb4',
'dbcollat' => 'utf8mb4_unicode_ci'

Then in Android use textView.getText().toString(); then send the text without using any encode or escape

Answer 5

In my case all text in message disappears after symbols & and +, so I decided to replace them before sending and after receiving and it works well for me.

private String encodeMessage(String message) {
    message = message.replaceAll("&", ":and:");
    message = message.replaceAll("\\+", ":plus:");
    return StringEscapeUtils.escapeJava(message);
}

private String decodeMessage(String message) {
    message = message.replaceAll(":and:", "&");
    message = message.replaceAll(":plus:", "+");
    return StringEscapeUtils.unescapeJava(message);
}

Answer 6

You can encode and decode emoticons without using any libraries in android if you are receiving unicode from your server .

Example :

U+1F601 is 16 bit unicode.

Replace U+ with 0x.

  int originalUnicode=0x1F601;
  textView.setText(getEmoticon(originalUnicode));


  public String getEmoticon(int originalUnicode) {
    return new String(Character.toChars(originalUnicode));
}

Answer 7

Convert unicode to emoji in whole content without using any library.

private String convertEmoji(String content) {
    content = content.replaceAll("U\\+", "0x");
    String keyword = "0x";

    int index = content.indexOf(keyword);
    int spaceIndex;

    while (index >=0){
        spaceIndex = content.indexOf(" ", index);

        if(spaceIndex > index) {
            String emoji = content.substring(index, spaceIndex);
            content = content.replaceAll(emoji, getEmoticon(Integer.decode(emoji)));
        }
        index = content.indexOf(keyword, index+keyword.length());
    }

    return content;
}