Format credit card in edit text in android

Question

How to make EditText accept input in format:

4digit 4digit 4digit 4digit 

I tried Custom format edit text input android to acc

Answer 1

Here's a simple and easily customizable solution using the TextWatcher class. It may be assigned to your EditText using the addTextChangedListener() method.

new TextWatcher() {
    /** Formats the Field to display user-friendly separation of the input values. */
    @Override public final void afterTextChanged(final Editable pEditable) {
        // Declare the separator.
        final char lSeparator      = '-';
        // Declare the length of separated text. i.e. (XXXX-XXXX-XXXX)
        final int  lSeparationSize = 4;
        // Declare the count; tracks the number of allowed characters in a row.
              int lCount          = 0;
        // Iterate the Characters.
        for(int i = 0; i < pEditable.length(); i++) {
            // Fetch the current character.
            final char c              = pEditable.charAt(i);
            // Is it a usual character. Here, we permit alphanumerics only.
            final boolean lIsExpected = (Character.isDigit(c) || Character.isLetter(c)) && (c != lSeparator);
            // Is the character expected?
            if(lIsExpected) {
                // Increase the count.
                lCount++;
            }
            else {
                // Is it a separator?
                if(c == lSeparator) {
                    // Reset the count.
                    lCount = 0;
                    // Continue the iteration.
                    continue;
                }
            }
            // Has the count been exceeded? Is there more text coming?
            if(lCount >= (lSeparationSize + 1) && (i < pEditable.length())) {
                // Reset the count.
                lCount = 0;
                // Insert the separator.
                pEditable.insert(i, Character.toString(lSeparator));
                // Increase the iteration count.
                i++;
            }
        }
    }
    /** Unused overrides. */
    @Override public final void beforeTextChanged(final CharSequence pCharSequence, final int pStart, final int pCount, final int pAfter) { }
    @Override public final void onTextChanged(final CharSequence pCharSequence, final int pStart, final int pBefore, final int pCount) { }
}

Alternatively, here is a much cleaner implementation based on epool's implementation.

public final class TextGroupFormattingListener implements TextWatcher {

    /* Member Variables. */
    private final int    mGroupLength;
    private final String mSeparator;
    private       String mSource;

    /** Constructor. */
    public TextGroupFormattingListener(final String pSeparator, final int pGroupLength) {
        // Initialize Member Variables.
        this.mSeparator   = pSeparator;
        this.mGroupLength = pGroupLength;
        this.mSource      = "";
    }

    /** Formats the Field to display user-friendly separation of the input values. */
    @Override public final void afterTextChanged(final Editable pEditable) {
        // Fetch the Source.
        String lSource = pEditable.toString();
        // Has the text changed?
        if (!this.getSource().equals(lSource)) {
            // Remove all of the existing Separators.
            lSource = lSource.replace(this.getSeparator(), "");
            // Allocate a StringBuilder.
            StringBuilder lStringBuilder = new StringBuilder();
            // Iterate across the Source String, which contains the raw user input.
            for(int i = 0; i < lSource.length(); i++) {
                // Have we exceeded the GroupLength?
                if(i > 0 && i % this.getGroupLength() == 0) {
                    // Append the separator.
                    lStringBuilder.append(this.getSeparator());
                }
                // Append the user's character data.
                lStringBuilder.append(lSource.charAt(i));
            }
            // Track changes to the Source.
            this.setSource(lStringBuilder.toString());
            // Replace the contents of the Editable with this new String.
            pEditable.replace(0, pEditable.length(), this.getSource());
        }
    }

    /** Unused overrides. */
    @Override public final void beforeTextChanged(final CharSequence pCharSequence, final int pStart, final int pCount, final int pAfter) { }
    @Override public final void onTextChanged(final CharSequence pCharSequence, final int pStart, final int pBefore, final int pCount)    { }

    public final int getGroupLength() {
        return this.mGroupLength;
    }

    public final String getSeparator() {
        return this.mSeparator;
    }

    private final void setSource(final String pSource) {
        this.mSource = pSource;
    }

    private final String getSource() {
        return this.mSource;
    }

}