How to detect text from a particular character in editText?

Question

I'm a complete beginner in android so please do excuse me if my question is foolish.Basically what I want to do is I want to detect text from occurance of # means for example if user is entering abc #hello then only #hello will be toasted in text change . So I tried to take reference from a github code and able to print all the # tags but I want to toast only current tag means if user is typing abc #hello #hi #bye //here current tag is #bye so I want to toast only the current tag upto the occurance of space on fly . I wonder how to modify my code to get the desired result.

Code:

editTxt.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            if(s.length()>0)
            showTags(s);
        }

        @Override
        public void afterTextChanged(Editable s) {

        }
    });


   //Methods
    private void showTags(CharSequence text) {

    int startIndexOfNextHashSign;

    int index = 0;
    while (index < text.length()-  1){
        sign = text.charAt(index);
        int nextNotLetterDigitCharIndex = index + 1; // we assume it is next. if if was not changed by findNextValidHashTagChar then index will be incremented by 1
        if(sign=='#'){
            startIndexOfNextHashSign = index;

            nextNotLetterDigitCharIndex = findNextValidHashTagChar(text, startIndexOfNextHashSign);
            Toast.makeText(this,text.subSequence(startIndexOfNextHashSign,nextNotLetterDigitCharIndex),Toast.LENGTH_LONG).show();
            //setColorForHashTagToTheEnd(startIndexOfNextHashSign, nextNotLetterDigitCharIndex);
        }

        index = nextNotLetterDigitCharIndex;
    }
}


private int findNextValidHashTagChar(CharSequence text, int start) {

    int nonLetterDigitCharIndex = -1; // skip first sign '#"
    for (int index = start + 1; index < text.length(); index++) {

        char sign = text.charAt(index);

        boolean isValidSign = Character.isLetterOrDigit(sign) || mAdditionalHashTagChars.contains(sign);
        if (!isValidSign) {
            nonLetterDigitCharIndex = index;
            break;
        }
    }
    if (nonLetterDigitCharIndex == -1) {
        // we didn't find non-letter. We are at the end of text
        nonLetterDigitCharIndex = text.length();
    }

    return nonLetterDigitCharIndex;
}

Github Project

Answer 1

As a reference to above answer although it's a great answer but it'll always toast the last hashtag means let's take an example if the entered text is abc #hi #hello even if we'll move the cursor to #hi and change it to #bye it would toast the las tag i.e #hello so for solving this we can use current cursor position

So the final code is :

editTxt.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s)
        {
            String sampleText = s.toString().substring(0,editTxt.getSelectionStart());
            String[] wordSplit = sampleText.split(" ");
            String sign=null;
            for (int i = wordSplit.length-1; i >= 0; i--){
             if(wordSplit[i].contains("#")){
       Toast.makeText(getApplicationContext(), wordSplit[i].substring(wordSplit[i].lastIndexOf("#")), Toast.LENGTH_SHORT).show();
                     break;
                }
            }

        }
    });

Answer 2

Try this one

String sampleText = "abc #hello #hi #bye";
String[] wordSplit = sampleText.split(" ");

for (int i = wordSplit.length-1; i >= 0; i--){
   if(wordSplit[i].contains("#")){
        Toast.makeText(getContext(), wordSplit[i].substring(wordSplit[i].indexOf("#")), Toast.LENGTH_SHORT).show();
        break;
   }
}

Edit: try using this instead of indexOf

lastIndexOf("#")

Answer 3

try this : may help you

    String sampleText = "abc#hello#hi#bye";
    String[] wordSplit = sampleText.split("#");

        for (int i = wordSplit.length - 1; i >= 0; i--) {
            Toast.makeText(this, wordSplit[wordSplit.length - 1], Toast.LENGTH_SHORT).show();
            break;
        }

Answer 4

So your TextWatcher will look like this

editTxt.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s)
        {
            String[] wordSplit = s.toString().split(" ");

            for (int i = wordSplit.length-1; i >= 0; i--){
                if(wordSplit[i].contains("#")){
                    Toast.makeText(getApplicationContext(), wordSplit[i], Toast.LENGTH_SHORT).show();
                    break;
                }
            }
        }
    });