I'm writing a CashRegister program and I'm currently working on the CashierView where I have added an option for the Cashier to input the amount of cash received by the customer. I now formatted it so that the user only can input numbers and 1 period. I now want to limit the numbers you can input after the period to two. I'm struggling to make this work.
I commented out one of the codes that I tried, but didn't work, incase it might be interesting.
Appreciate all the help!
Br,
Victor
private void jCashReceivedKeyTyped(java.awt.event.KeyEvent evt) {
char c = evt.getKeyChar(); //Allows input of only Numbers and periods in the textfield
//boolean tail = false;
if ((Character.isDigit(c) || (c == KeyEvent.VK_BACKSPACE) || c == KeyEvent.VK_PERIOD)) {
int period = 0;
if (c == KeyEvent.VK_PERIOD) { //Allows only one period to be added to the textfield
//tail = false;
String s = getTextFieldCash();
int dot = s.indexOf(".");
period = dot;
if (dot != -1) {
evt.consume();
}
}
//. if (tail=true){ //This is the code that I tried to use to limit input after the period to two
// String x = getTextFieldCashTail();
// if (x.length()>1){
// evt.consume();
// }
// }
}
else {
evt.consume();
}
}
If you're dead set on doing this with a KeyEvent, here's one possible method:
private void jCashReceivedKeyTyped(java.awt.event.KeyEvent evt) {
char c = evt.getKeyChar(); //Allows input of only Numbers and periods in the textfield
if ((Character.isDigit(c) || (c == KeyEvent.VK_BACK_SPACE) || c == KeyEvent.VK_PERIOD)) {
String s = getTextFieldCash();
int dot = s.indexOf(".");
if(dot != -1 && c == KeyEvent.VK_PERIOD) {
evt.consume();
} else if(dot != -1 && c != KeyEvent.VK_BACK_SPACE){
String afterDecimal = s.substring(dot + 1);
if (afterDecimal.length() > 2) {
evt.consume();
}
}
}
}
Hope this helps. Just keep in mind that by listening to a KeyEvent, if someone copies and pastes values into your JTextField, this won't catch that. If you want to catch any possible type of input, you'll want to use a DocumentListener. If you're wondering how to use a DocumentListener, here is some code that shows how to use it on a JTextField.
I'm creating a GUI for a club and am trying to set up a test so that when a new user is prompted to input their name, they will not be able to input any numeric values.
Here is the code I have so far:
else if((this.jTextFieldName.getText() ){
errorMessage = "Name is not acceptable";
this.jTextFieldNameActionPerformed(requestFocusInWindow());
}
The space after getText() in the first line is where I need to input a test but I can't find a way to do this that works.
Can anyone help?
The best way in swing is if you are using PlainDocument as document for your textComponent. It's to use a DocumentFilter. Take a look in how to do it in Text Component Features implementing a DocumentFilter. You have to override ìnsertString method then there you can use your regex. Here you have an example using DocumentFilter.
Why not try with a regex?
else if(this.jTextFieldName.getText().matches(".*\\d+.*") ){
If you can then go for it
jTextField.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
char c = e.getKeyChar();
if (!((c >= 'a') && (c <= 'z') || (c >= 'A') && (c <= 'Z') ||
(c == KeyEvent.VK_BACK_SPACE) ||
(c == KeyEvent.VK_DELETE))) {
getToolkit().beep();
//JOptionPane.showMessageDialog(rootPane, "Enter only Alphabets");
e.consume();
}
}
});
Try the regex ^[0-9]+$.
You can implement it like this:
this.jTextFieldName.getText().matches("^[0-9]+$")
Trying to make the text field accept only integers
some how it either consumes everything I type in the field or it just lets to type anything
it's simple that's why its hard to find the problem.
JLabel year = new JLabel("Year:");
final JTextField yeart = new JTextField(10);
yeart.addKeyListener(new KeyAdapter()
{
#Override
public void keyTyped(KeyEvent e)
{
super.keyTyped(e);
e.getKeyCode();
if (!(e.getKeyCode() >= 48 || e.getKeyCode() <= 57))
{
e.consume();
}
}
});
Use && instead ||. (!(e.getKeyCode() >= 48 || e.getKeyCode() <= 57)) will simply return false for every input.
I've got one textField where I only accept numbers from the keyboard, but now I have to change it as it's a "price textField" and I would also need to accept a dot "." for any kind of prices.
How can I change this in order to get what I need?
ptoMinimoField = new JTextField();
ptoMinimoField.setBounds(348, 177, 167, 20);
contentPanel.add(ptoMinimoField);
ptoMinimoField.setColumns(10);
ptoMinimoField.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
char caracter = e.getKeyChar();
if (((caracter < '0') || (caracter > '9'))
&& (caracter != '\b')) {
e.consume();
}
}
});
As suggested by Oracle ,Use Formatted Text Fields
Formatted text fields provide a way for developers to specify the valid set of characters that can be typed in a text field.
amountFormat = NumberFormat.getNumberInstance();
...
amountField = new JFormattedTextField(amountFormat);
amountField.setValue(new Double(amount));
amountField.setColumns(10);
amountField.addPropertyChangeListener("value", this);
I just use a try-catch block:
try {// if is number
Integer.parseInt(String);
} catch (NumberFormatException e) {
// else then do blah
}
JTextField txField = new DoubleJTextField();
Create a file DoubleJTextField.java and be happy
public class DoubleJTextField extends JTextField {
public DoubleJTextField(){
addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
char ch = e.getKeyChar();
if (!isNumber(ch) && !isValidSignal(ch) && !validatePoint(ch) && ch != '\b') {
e.consume();
}
}
});
}
private boolean isNumber(char ch){
return ch >= '0' && ch <= '9';
}
private boolean isValidSignal(char ch){
if( (getText() == null || "".equals(getText().trim()) ) && ch == '-'){
return true;
}
return false;
}
private boolean validatePoint(char ch){
if(ch != '.'){
return false;
}
if(getText() == null || "".equals(getText().trim())){
setText("0.");
return false;
}else if("-".equals(getText())){
setText("-0.");
}
return true;
}
}
Don't ever use a KeyListener for this. Your code above has two serious bugs, both caused by the use of a KeyListener. First, it will miss any text that gets pasted in. Whenever I find a field that filters out non-digits, I always try to paste in some text, just for fun. Nine times out of ten, the text gets accepted, because they used a key listener.
Second, you didn't filter out modifiers. If the user tries to save their work by typing control-s while they're in this field, your key listener will consume the event. And if your application assigns, say, a control-5 or alt-5 shortcut to some action, this KeyListener will add a 5 to the field when they type it, even though the user wasn't trying to type a character. You did figure out that you needed to pass the backspace key, but that's not all you need to pass. Your arrow keys won't work. Neither will your function keys. You can fix all these problems, but it starts to be a lot of work.
There's a third disadvantage, but it only shows up if you adapt your application to a foreign alphabet, particularly one that takes multiple keystrokes to generate a single character, like Chinese. These alphabets make KeyListeners useless.
The trouble is this. You need to filter characters, but KeyListeners aren't about characters, they're about keystrokes, which are not the same thing: Not all keystrokes generate characters, and not all characters are generated by keystrokes. You need an approach that looks at characters after they've been generated, and after modified keystrokes have already been filtered out.
The simplest approach is to use a JFormattedTextField, but I've never liked that approach, because it doesn't format or filter as you type. So instead, I will use a DocumentFilter. DocumentFilters don't operate on keystrokes, they operate on the text strings as they get inserted to your JTextField's data model. Hence, all the control-keys, arrow and function keys and such don't even reach the DocumentFilter. All pasted text goes through the DocumentFilter, too. And, for languages that take three keystrokes to generate a single character, the DocumentFilter doesn't get invoked until the character is generated. Here's what it looks like:
ptoMinimoField = new JTextField();
ptoMinimoField.setBounds(348, 177, 167, 20); // Don't do this! See below.
contentPanel.add(ptoMinimoField);
ptoMinimoField.setColumns(10);
PlainDocument document = (PlainDocument) ptoMinimoField.getDocument();
document.setDocumentFilter(new DigitFilter());
}
The DigitFilter class looks like this:
public class DigitFilter extends DocumentFilter {
#Override
public void insertString(FilterBypass fb, int offset, String text,
AttributeSet attr) throws BadLocationException {
super.insertString(fb, offset, revise(text), attr);
}
#Override
public void replace(FilterBypass fb, int offset, int length, String text,
AttributeSet attrs) throws BadLocationException {
super.replace(fb, offset, length, revise(text), attrs);
}
private String revise(String text) {
StringBuilder builder = new StringBuilder(text);
int index = 0;
while (index < builder.length()) {
if (accept(builder.charAt(index))) {
index++;
} else {
// Don't increment index here, or you'll skip the next character!
builder.deleteCharAt(index);
}
}
return builder.toString();
}
/**
* Determine if the character should remain in the String. You may
* override this to get any matching criteria you want.
* #param c The character in question
* #return true if it's valid, false if it should be removed.
*/
public boolean accept(final char c) {
return Character.isDigit(c) || c == '.';
}
}
You could write this as an inner class, but I created a separate class so you can override the accept() method to use any criteria you want. You may also notice that I don't test for digits by writing this:
(c < '0') || (c > '9')
Instead, I do this:
Character.isDigit()
This is faster, cleaner, and works with foreign numbering systems. I also don't need your test for the backspace character, '\b'. I'm guessing that your first KeyListener was filtering out the backspace key, which was your first clue that it was the wrong approach.
And on an unrelated note, don't hard code your component positions. Learn how to use the LayoutManagers. They're easy to use, and they'll make your code much easier to maintain.
Have you looked at a JFormattedTextField? It would seem it does what you want.
Enter the double number of JTextField in java
private boolean dot = false;
private void txtMarkKeyTyped(java.awt.event.KeyEvent evt) {
char vChar = evt.getKeyChar();
if (txtMark.getText().equals(""))
dot = false;
if (dot == false){
if (vChar == '.') dot = true;
else if (!(Character.isDigit(vChar)
|| (vChar == KeyEvent.VK_BACK_SPACE)
|| (vChar == KeyEvent.VK_DELETE))) {
evt.consume();
}
} else {
if (!(Character.isDigit(vChar)
|| (vChar == KeyEvent.VK_BACK_SPACE)
|| (vChar == KeyEvent.VK_DELETE))) {
evt.consume();
}
}
}
This bit of code;
if (((caracter < '0') || (caracter > '9'))
&& (caracter != '\b')) {
decides whether to consume the key event. You need to update the condition so it doesn't consume the dot character.
Just right click on TextField / events / key / keytyped
if(!Character.isDigit(evt.getKeyChar())){
evt.consume();}
/////////////
JTextField ptoMinimoField = new JTextField();
ptoMinimoField.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
boolean ret = true;
try {
Double.parseDouble(ptoMinimoField.getText()+e.getKeyChar());
}catch (NumberFormatException ee) {
ret = false;
}
if (!ret) {
e.consume();
}
}
});
maybe can help you for filtering keytyped just number and dot
public void filterHanyaAngkaDot(java.awt.event.KeyEvent evt){
char c = evt.getKeyChar();
if (! ((Character.isDigit(c) ||
(c == KeyEvent.VK_BACK_SPACE) ||
(c == KeyEvent.VK_DELETE))
)&& c==KeyEvent.VK_COMMA
)
{
evt.consume();
}
}
JTextField txtMyTextField = new JTextField();
numOnly(txtMyTextField);
public void numOnly(Object objSource){
((Component) objSource).addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
String filterStr = "0123456789.";
char c = (char)e.getKeyChar();
if(filterStr.indexOf(c)<0){
e.consume();
}
}
#Override
public void keyReleased(KeyEvent e) {}
#Override
public void keyPressed(KeyEvent e) {}
});
}
WARNING: This function does not follow proper java documentation
guide.
I have been using this solution, it's simple and efficient:
jtextfield.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
char vChar = e.getKeyChar();
if (!(Character.isDigit(vChar)
|| (vChar == KeyEvent.VK_BACK_SPACE)
|| (vChar == KeyEvent.VK_DELETE))) {
e.consume();
}
}
});
private boolean point = false;
private void txtProductCostPriceAddKeyTyped(java.awt.event.KeyEvent evt)
{
char Char = evt.getKeyChar();
if (txtProductCostPriceAdd.getText().equals(""))
point = false;
if (point == false){
if (Char == '.') point = true;
else if (!(Character.isDigit(Char) || (Char == KeyEvent.VK_BACK_SPACE) || (Char == KeyEvent.VK_DELETE))) {
evt.consume();
}
} else {
if (!(Character.isDigit(Char) || (Char == KeyEvent.VK_BACK_SPACE) || (Char == KeyEvent.VK_DELETE))) {
evt.consume();
}
}
}
JTextField textField = new JTextField();
textField.setColumns(10);
textField.addKeyListener(new KeyAdapter() {
#Override
public void KeyTyped(KeyEvent e) {
if (!(e.getKeyChar() >= '0' && e.getKeyChar() <= '9')) {
e.consume();
}
}
})
this is the easiest method i have found so far, and it works without any error
I think this may be very simple, but it swallow my time.
I am using TextItem In GWT in my JAVA Application to get the price input from the the user.
I am trying to stop allowing more than one dot (".") on text item. All my exercise are gone to fail.
I am using regular expression; Try to handle the key chars on BlurHandler event of TextItem both drag me a wrong.
Can anybody help me to achieve the above?
Thank you in advance.
Something like this is what I use:
amount = new TextBox();
amount.setVisibleLength(10);
amount.addKeyPressHandler(new KeyPressHandler() {
public void onKeyPress(KeyPressEvent event) {
if (!checkNumeric(amount.getText(), event.getCharCode()))
amount.cancelKey();
}
});
public boolean checkNumeric(String text, char keycode) {
if (!Character.isDigit(keycode) && keycode != '.' && keycode != '-'
&& keycode != KeyCodes.KEY_BACKSPACE
&& keycode != KeyCodes.KEY_TAB) {
return false;
}
if (keycode == '-') {
if (!text.isEmpty()) {
return false;
}
}
if (keycode == '.') {
if (text.contains(".")) {
return false;
}
}
return true;
}