The JFormattedTextField with NumberFormatter and DecimalFormat can exhibit strange behavior in certain scenarios. Some common issues include incorrect formatting, incorrect parsing, and unexpected behavior when editing the text field.
To resolve these issues, it is recommended to use the following best practices:
Clearly define the format pattern for the DecimalFormat object using the appropriate format string.
Use the setValueClass() method to specify the type of value that the NumberFormatter should parse and format.
Use the setMinimum() and setMaximum() methods to set the minimum and maximum values that can be entered into the text field.
Use the setCommitsOnValidEdit() method to specify whether the text field should commit its value when the user presses Enter or moves focus away from the field.
For example:
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DecimalFormat decimalFormat = new DecimalFormat("0.00");
NumberFormatter numberFormatter = new NumberFormatter(decimalFormat);
numberFormatter.setValueClass(Double.class);
numberFormatter.setMinimum(0.0);
numberFormatter.setMaximum(100.0);
numberFormatter.setCommitsOnValidEdit(true);
JFormattedTextField formattedTextField = new JFormattedTextField(numberFormatter);
By following these best practices, you can avoid common issues with the JFormattedTextField and ensure that it behaves as expected.
To resolve this issue, you can try several approaches.
Override the valueToString method in the NumberFormatter or DecimalFormat class to return the correct string representation of the value.
Use a custom FormatterFactory to return a custom Formatter that implements the correct behavior.
Use a JSpinner instead of a JFormattedTextField to display the number, as JSpinner automatically handles formatting and parsing of numbers.
Use a custom DocumentFilter to limit the characters that can be entered into the JFormattedTextField to only those that are valid for the NumberFormatter or DecimalFormat.