使用荧光笔的java.lang.ArrayIndexOutOfBoundsException(java.lang.ArrayIndexOutOfBoundsException using highli

使用荧光笔的java.lang.ArrayIndexOutOfBoundsException(java.lang.ArrayIndexOutOfBoundsException using highlighter)

我正在尝试从JTextField获取选定的文本。 我找到了.getHighlighter（）函数，它可以工作。 我得到了所需的文本，但它不断抛出和索引越界异常。 谁能告诉我为什么？

PS：我也试过检查h！= null和h [0]！= null。 结果相同。

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())); }

例外：

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)

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)

最满意答案

你需要像这样检查数组长度

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())); } }

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())); } }