java.lang.ArrayIndexOutOfBoundsException mit Textmarker

Question

Ich versuche, ausgewählten Text von einem JTextField zu erhalten. Ich habe die Funktion .getHighlighter() gefunden und es funktioniert. Ich bekomme den gewünschten Text, aber es bleibt die Ausnahme für das Werfen und den Index außerhalb des gültigen Bereichs. Kann mir jemand sagen warum?

PS: Ich habe auch versucht zu überprüfen, ob h! = Null und h [0]! = Null. Gleiches Ergebnis.

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())); 
} 

Ausnahme:

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) 

Answer 1

Sie müssen auch Array-Länge überprüfen, wie diese

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())); 
     } 
    }