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JavaFX TextField validation for integer input and also allow either K or k(for Thousand) or M or m(for Million) in last

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鱼传尺愫
鱼传尺愫 2021-01-21 11:40

I want to add validation in javafx TextField such that user should only be able to insert integer values ([0-9] and Dot ). Also user should be able to insert either B or b(for B

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  • 北恋
    北恋 (楼主)
    2021-01-21 12:11

    I created the following class to filter input on TextField, which also uses the TextFormatter introduced in JavaFX 8. 

    public class TextFieldValidator {

    private static final String CURRENCY_SYMBOL   = DecimalFormatSymbols.getInstance().getCurrencySymbol();
    private static final char   DECIMAL_SEPARATOR = DecimalFormatSymbols.getInstance().getDecimalSeparator();

    private final Pattern       INPUT_PATTERN;

    public TextFieldValidator(@NamedArg("modus") ValidationModus modus, @NamedArg("maxCountOf") int maxCountOf) {
        this(modus.createPattern(maxCountOf));
    }

    public TextFieldValidator(@NamedArg("regex") String regex){
        this(Pattern.compile(regex));
    }

    public TextFieldValidator(Pattern pattern){ 
        INPUT_PATTERN = pattern;
    }

    public static TextFieldValidator maxFractionDigits(int maxCountOf) {
        return new TextFieldValidator(maxFractionPattern(maxCountOf));
    }

    public static TextFieldValidator maxIntegers(int maxCountOf) {
        return new TextFieldValidator(maxIntegerPattern(maxCountOf));
    }

    public static TextFieldValidator integersOnly() {
        return new TextFieldValidator(integersOnlyPattern());
    }

    public TextFormatter getFormatter() {
        return new TextFormatter<>(this::validateChange);
    }

    private Change validateChange(Change c) {
        if (validate(c.getControlNewText())) {
            return c;
        }
        return null;
    }

    public boolean validate(String input) {
        return INPUT_PATTERN.matcher(input).matches();
    }

    private static Pattern maxFractionPattern(int maxCountOf) {
        return Pattern.compile("\\d*(\\" + DECIMAL_SEPARATOR + "\\d{0," + maxCountOf+ "})?");
    }

    private static Pattern maxCurrencyFractionPattern(int maxCountOf) {
        return Pattern.compile("^\\" + CURRENCY_SYMBOL + "?\\s?\\d*(\\" + DECIMAL_SEPARATOR + "\\d{0," + maxCountOf+ "})?\\s?\\" +
                CURRENCY_SYMBOL + "?");
    }

    private static Pattern maxIntegerPattern(int maxCountOf) {
        return Pattern.compile("\\d{0," + maxCountOf+ "}");
    }

    private static Pattern integersOnlyPattern() {
        return Pattern.compile("\\d*");
    }

    public enum ValidationModus {

        MAX_CURRENCY_FRACTION_DIGITS {
            @Override
            public Pattern createPattern(int maxCountOf) {
                return maxCurrencyFractionPattern(maxCountOf);
            }
        },

        MAX_FRACTION_DIGITS {
            @Override
            public Pattern createPattern(int maxCountOf) {
                return maxFractionPattern(maxCountOf);
            }
        },
        MAX_INTEGERS {
            @Override
            public Pattern createPattern(int maxCountOf) {
                return maxIntegerPattern(maxCountOf);
            }
        },

        INTEGERS_ONLY {
            @Override
            public Pattern createPattern(int maxCountOf) {
                return integersOnlyPattern();
            }
        };

        public abstract Pattern createPattern(int maxCountOf);
    }
}



    You can use it like this:
    


    textField.setTextFormatter(new TextFieldValidator(ValidationModus.MAX_INTEGERS, 4).getFormatter());

    


    or you can instantiate it in a fxml file, and apply it to a customTextField with the according properties. 
    


    app.fxml:
    


    
    




    


    CustomTextField:
    


    public class CustomTextField {

private TextField textField;

public CustomTextField(@NamedArg("validator") TextFieldValidator validator) {
        this();
        textField.setTextFormatter(validator.getFormatter());
    }
}

    


    For your usecase you could call the TextFieldValidor constructor with the appropriate regex pattern and add the filter of James-D's answer to validateChange(Change c)
    
    
    
             
    
                                                        
    
            
            
    
              
                
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