사용자가 버튼을 클릭하여 탐색 할 때 제거되거나 추가되는 여러 패널이 포함 된 메뉴를 만드는 중입니다.JPanels를 바꿀 때 오류가 발생합니다.
다양한 것들을 시도한 후에, 나는 가장 감각적이지만 오류를주는 사람에게갔습니다.
내 오류를 생산하는 "솔루션"어떤 이유
public void actionPerformed (ActionEvent evt) {
Object source = evt.getSource();
if (source == jButton1) {
changePanels(jPanel1, singlePanel1);
}
}
public void changePanels (JPanel a, JPanel b) {
getContentPane().removeAll();
getContentPane().add(b);
validate();
repaint();
}
, 그것은 이러한 오류 발생 : 나는 다양한 문제 해결을 통해 실행했습니다
$Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.awt.Container.addImpl(Container.java:1041)
at java.awt.Container.add(Container.java:365)
at phantasma.OriginalFrame.changePanels(OriginalFrame.java:156)
at phantasma.OriginalFrame.actionPerformed(OriginalFrame.java:149)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6288)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6053)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4651)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:643)
at java.awt.EventQueue.access$000(EventQueue.java:84)
at java.awt.EventQueue$1.run(EventQueue.java:602)
at java.awt.EventQueue$1.run(EventQueue.java:600)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$2.run(EventQueue.java:616)
at java.awt.EventQueue$2.run(EventQueue.java:614)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:613)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
을,하지만 난 모르겠어요 무엇을 문제는 도움이 대단히 감사합니다, 감사합니다.
가 null이 될 singlePanel1 수있다? –
Russ의 코멘트에 대해서 : 빈 샌드 박스 응용 프로그램을 만들고이 메소드를 사용하여 * null *이 아닌 두 개의 패널을 바꿔보십시오. 그것이 효과가 있는지보기. – wchargin
일단 NPE를 수정하면'CardLayout'을 사용하십시오. –