java.lang.ArrayIndexOutOfBoundsException using highlighter

Question

I'm trying to get selected text from a JTextField. I found the .getHighlighter() function and it works. I get the desired text but it keeps throwing and index out of bounds exception. Can anybody tell me why?

PS: I've also tried checking if h != null and h[0] != null. Same result.

private void jTextField1MouseDragged(java.awt.event.MouseEvent evt) {                                         
    Highlight[] h = jTextField1.getHighlighter().getHighlights();
    jLabel2.setText("Selected text: " + jTextField1.getText().substring(h[0].getStartOffset(), h[0].getEndOffset()));
}

Exception:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0
at interfacesprueba1.Ej3b.jTextField1MouseDragged(Ej3b.java:110)
at interfacesprueba1.Ej3b.access$000(Ej3b.java:14)
at interfacesprueba1.Ej3b$1.mouseDragged(Ej3b.java:42)
at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:320)
at java.awt.Component.processMouseMotionEvent(Component.java:6583)
at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:3342)
at java.awt.Component.processEvent(Component.java:6304)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4542)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Please, post values of `jTextField1.getText()`, `h[0].getStartOffset()` and `h[0].getEndOffset()` — default locale, Sep 13 '16 at 07:32
Have you checked that there are any highlights? `h.length > 0` — default locale, Sep 13 '16 at 07:33
I've just tried h.length and it's not working. The values asked are qwerty, 2,3 (with the E in querty selected). — Sergio Tx, Sep 13 '16 at 07:37
Possible duplicate of [What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?](http://stackoverflow.com/questions/5554734/what-causes-a-java-lang-arrayindexoutofboundsexception-and-how-do-i-prevent-it) — ChiefTwoPencils, Sep 13 '16 at 07:37
I know what causes IndexOutOfBounds Exception. My problem is with getHighlighter() method. — Sergio Tx, Sep 13 '16 at 07:39
You really should try to avoid one-liners like that sentence. It makes reading and debugging the code way more difficult. — SJuan76, Sep 13 '16 at 07:40
But if you know then you can tell by your exception that, with an index of 0, you're going out of bounds on your array. What line of code is 110? — ChiefTwoPencils, Sep 13 '16 at 07:41

score 1 · Accepted Answer · answered Sep 13 '16 at 07:36

1

You need to check array length also like this

private void jTextField1MouseDragged(java.awt.event.MouseEvent evt) {
        Highlight[] h = jTextField1.getHighlighter().getHighlights();
        if (h != null && h.length > 0) {
            jLabel2.setText(
                    "Selected text: " + jTextField1.getText().substring(h[0].getStartOffset(), h[0].getEndOffset()));
        }
    }

answered Sep 13 '16 at 07:36

Jekin Kalariya

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I don't think the [method](https://docs.oracle.com/javase/7/docs/api/javax/swing/text/Highlighter.html#getHighlights()) ever returns `null`. – ChiefTwoPencils Sep 13 '16 at 07:39
ya we can directly check for length,i have just do null check for safer side :) – Jekin Kalariya Sep 13 '16 at 07:40
Same exception. – Sergio Tx Sep 13 '16 at 07:40
OK, I was testing something else. It did fix the problem. – Sergio Tx Sep 13 '16 at 07:45

java.lang.ArrayIndexOutOfBoundsException using highlighter

1 Answers1