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I want to create a input dialog box when new record is created and save the user input as input into the file.
Here is the code :
String input = JOptionPane.showInputDialog(null, "Enter name : ", "New Record!", 1); //This to let user input name
try
{
JOptionPane.showMessageDialog(null, "Thanks for playing.", "Thanks", 1); //Show this dialog after user input
HighestScoreFile.HighestScoreFile(input, hours, minutes, seconds, click); //Store the data into a file, the `method` is in another class.
}
catch(IOException ex){}
When there is no user input or any input, the OK button work fine, but if I click the cancelbutton, it returns these errors :
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at HighestScoreFile.HighestScoreFile(HighestScoreFile.java:22)
at MemoryGame$ButtonListener.actionPerformed(MemoryGame.java:329)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
at java.awt.EventQueue.access$000(EventQueue.java:101)
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:680)
at java.awt.EventQueue$4.run(EventQueue.java:678)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
How can I solve it?
372
If the user clicks "cancel", the response will be null. If they click "ok" without entering any text the response will be the empty string. But your code does not handle a situation, if you your input is empty and you hit OK button.
With this method we can prompt the user for input while customizing our dialog window. The showConfirmDialog returns either String or Object and can be called using the following combinations of parameters: Object (returns String) – Shows a question-message dialog requesting input from the user.
JOptionPane makes it easy to pop up a standard dialog box that prompts users for a value or informs them of something. For information about using JOptionPane , see How to Make Dialogs, a section in The Java Tutorial. Asks a confirming question, like yes/no/cancel.
String input = ....
if (input!=null) { ...
If the user clicks on "cancel", input will be null.
You should enter the try block only if the user clicks on "ok" or you should add an if to check if input is null before trying to use it!
Now, you can actually disable the cancel button with
JOptionPane.showInputDialog(null, "Enter name : ", "New Record!", JOptionPane.OK_OPTION);
or checking if the user clicked on cancel with
if (input == null){
// Do something
} else {
try {
JOptionPane.showMessageDialog(null, "Thanks for playing.", "Thanks", 1);
HighestScoreFile.HighestScoreFile(input, hours, minutes, seconds, click);
} catch(IOException ex){}
}
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