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Thread: Pressing Cancel in FileDialog close entire application (Using SWT)

  1. #1
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    Default Pressing Cancel in FileDialog close entire application (Using SWT)

    HI,

    when I open a file dialog from my application and press the cancel button located within the file dialog, it just closes the file dialog as expected, if I repeat the process, it closes the entire application, that would be my main shell which has my menubar, as well as a number of other things and the application window which holds the button the activates the file dialog.

    this is the error log that it gives

    ImportWindow is the application window
    AppMainShell is the class the creates the main Shell
    I can include code, but wasnt sure what to put here.

    I have included an image to give the basic idea of what it looks like

    pic.jpg

    #
    java.lang.NullPointerException
    at app.GUIConstructionModule.ImportWindow$4.widgetSelected(ImportWindow.java:324)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
    at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
    at app.GUIConstructionModule.ImportWindow.openWindow(ImportWindow.java:74)
    at app.GUIConstructionModule.ImportWindow.<init>(ImportWindow.java:41)
    at app.GUIConstructionModule.AppMenu$2.widgetSelected(AppMenu.java:181)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
    at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
    at app.GUIConstructionModule.AppMainShell.setupWindow(AppMainShell.java:30)
    at app.GUIConstructionModule.AppMainShell.<init>(AppMainShell.java:16)
    at app.ConstructApp.<init>(ConstructApp.java:24)
    at app.ConstructApp.main(ConstructApp.java:36)
    java.lang.NullPointerException
    at app.GUIConstructionModule.ImportWindow$6.widgetSelected(ImportWindow.java:352)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
    at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
    at app.GUIConstructionModule.AppMainShell.setupWindow(AppMainShell.java:30)
    at app.GUIConstructionModule.AppMainShell.<init>(AppMainShell.java:16)
    at app.ConstructApp.<init>(ConstructApp.java:24)
    at app.ConstructApp.main(ConstructApp.java:36)




    I appreciate any help


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Pressing Cancel in FileDialog close entire application (Using SWT)

    java.lang.NullPointerException
    at app.GUIConstructionModule.ImportWindow$4.widgetSel ected(ImportWindow.java:324)
    There is a variable with a null value on line 324. Look at line 324 in the your source and see what variable is null. Then backtrack in the code to see why that variable does not have a valid value.
    If you can not tell which variable it is, add a println just before line 324 and print out the values of all the variables on that line.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Pressing Cancel in FileDialog close entire application (Using SWT)

    Cool thanks you nailed it, so obvious in retrospect, I appreciate your input, this is the segment that was crashing the application



    mainfileButton.addSelectionListener(new SelectionAdapter() {
     
    				 public void widgetSelected(SelectionEvent e) {
     
     
    					 main = new FileDialog(shell, SWT.OPEN);
    					 String path = main.open();
     
     
    					 /*
    					 if(!path.isEmpty()){
     
    						 mainfilePathHolder.setText (path);
     
    					 }
    					 */
    				 }
    			});

    when my if statement gets validated, if cancel is pushed, path is null.
    The weird thing remains,for some reason, it would only crash after repeating the error on the second time, but yes Im going to chuck in a try, catch statement to solve it.

    Thank you very much!

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Pressing Cancel in FileDialog close entire application (Using SWT)

    going to chuck in a try, catch statement
    An if statement would be better.
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: Pressing Cancel in FileDialog close entire application (Using SWT)

    Cool, changed it to an if statement, works great, thank you

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