ユーザーが配列内のデータを検索できるようにする atextfieldと aを作成する次のコードがあります。button
//Creates a form to search data, list for it and buttons to sort the list.
rightPanel.add(Box.createRigidArea(new Dimension(20, 20)));
final TextField searchTextField;
searchTextField = new TextField ();
rightPanel.add(searchTextField);
rightPanel.add(Box.createRigidArea(new Dimension(20, 20)));
JButton searchConfirmButton = new JButton("Search");
rightPanel.add(searchConfirmButton);
searchConfirmButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
try {
search = searchTextField.getText();
int index = Arrays.asList(data).indexOf(search);
for (String result : data) {
if (result.contains(search)) {
System.out.println(result);
System.out.println(index);
}
}
} catch (NullPointerException e1) {
}
}
});
しかし、データが存在するかどうかにかかわらず、データを検索するたびに、プログラムはnullpointerexception次の内容を返します。
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at program.Program$4$1.actionPerformed(Program.java:233)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
この場合、行 233 にはこの行が含まれます。if (result.contains(search)) {