[jdk20] RFR: 4512626: Non-editable JTextArea provides no visual indication of keyboard focus [v2]

[Alexander Zvegintsev]

On Fri, 16 Dec 2022 19:59:30 GMT, Alexander Zuev <kizune at openjdk.org> wrote:

>> src/java.desktop/share/classes/javax/swing/text/DefaultCaret.java line 389:
>> 
>>> 387:             } else {
>>> 388:                 if (getBlinkRate() != 0) {
>>> 389:                     savedBlinkRate = getBlinkRate();
>> 
>> Look like this can override blink rate set by user:
>> 
>> 
>> import javax.swing.JButton;
>> import javax.swing.JFrame;
>> import javax.swing.JTextField;
>> import javax.swing.SwingUtilities;
>> import java.awt.BorderLayout;
>> import java.awt.Component;
>> import java.awt.Robot;
>> import java.lang.reflect.InvocationTargetException;
>> 
>> public class CaretThing {
>> 
>>     static JFrame frame;
>>     static JTextField textField;
>>     static Robot robot;
>>     static JButton button;
>> 
>>     static void printBlinkRate() {
>>         System.err.println("Caret blink rate: " + textField.getCaret().getBlinkRate());
>>     }
>> 
>>     static void requestFocus(Component component) throws InterruptedException, InvocationTargetException {
>>         robot.waitForIdle();
>>         robot.delay(300);
>> 
>>         SwingUtilities.invokeAndWait(() -> {
>>             System.err.println("Requesting focus on " + component);
>>             printBlinkRate();
>>             component.requestFocus();
>>             printBlinkRate();
>>         });
>>     }
>> 
>>     static void changeEditable() throws InterruptedException, InvocationTargetException {
>>         robot.waitForIdle();
>>         robot.delay(300);
>>         SwingUtilities.invokeAndWait(()-> {
>>             System.err.println("Changing editable");
>>             printBlinkRate();
>>             textField.setEditable(!textField.isEditable());
>>             printBlinkRate();
>>         });
>>     }
>> 
>>     public static void main(String[] args) throws Exception {
>>         robot = new Robot();
>>         robot.setAutoWaitForIdle(true);
>>         robot.setAutoDelay(50);
>> 
>>         SwingUtilities.invokeAndWait(() -> {
>>             frame = new JFrame("Hey");
>>             frame.setLocationRelativeTo(null);
>>             textField = new JTextField("Some long field value");
>> 
>>             textField.setEditable(false);
>>             frame.setLayout(new BorderLayout());
>>             frame.add(textField, BorderLayout.NORTH);
>> 
>>             button = new JButton("Button");
>>             button.addActionListener((e)-> printBlinkRate());
>> 
>>             frame.add(button, BorderLayout.CENTER);
>>             frame.pack();
>>             frame.setVisible(true);
>> 
>>             button.requestFocus();
>>             textField.getCaret().setBlinkRate(2500);
>>         });
>> 
>>         requestFocus(textField);
>> 
>>         requestFocus(button); // comment this to get 0 blink rate on editable field
>> 
>>         changeEditable();
>> 
>>         requestFocus(textField);
>> 
>>         SwingUtilities.invokeAndWait(CaretThing::printBlinkRate);
>>     }
>> }
>> 
>> Running the sample above at least two possible misbehaviors(tested on Linux):
>> * you will receive blink rate `500` instead of user set `2500`
>> * but if you comment `requestFocus(button);` line then blink rate will be `0` (it shows non-blinking cursor)
>> 
>> <hr>
>> 
>> Other than that I am worried about `getBlinkRate()` does not return the same value as passed to`setBlinkRate()` (e.g. case when component is not editable, possible JCK issue?)
>
> I updated the code now the behaviour is correct (as far as i tested) and the blink rate is reported as if it is set to the correct value even on non-editable text element.

I am still having issue with non-blinking cursor on editable field with the latest version of the fix.

Fails for me with test provided above and commented `requestFocus(button);` line.

-------------

PR: https://git.openjdk.org/jdk20/pull/21