Question

My app have Preferences window. I open it using this code

- (IBAction)openPreferences:(id)sender {

    NSWindowController *windowController = [[NSWindowController alloc] initWithWindowNibName:@"Preferences"];
    [windowController window];
}

如果新闻command,将再次打开新的优惠窗口......

如何只打开一个窗口? 感谢!

Answer 1

窗口主计长,一个实例变数,可以改变你的公开选择

- (IBAction)openPreferences:(id)sender
{
    if( windowController == nil )
        windowController = [[NSWindowController alloc] initWithWindowNibName:@"Preferences"];
    [windowController showWindow:sender];
}

Answer 2

So this is how I solved it... I have a class "MyPreferencesWindowController" which has a method called getInstance. This method is what is called when you want to get the preferences window. This solution takes advantage of singleton technology.

/**
Method in my MyPreferencesWindowController.m file
with a corresponding method in the .h file.
*/
+(id) getInstance {

    static PreferencesWindowController *instance = nil;
    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{
        instance = [[self alloc] init];
    });
    return instance;
}

现在,在文件类别中,当你想展示优惠窗口时,我们做以下工作:

-(IBAction) showPreferences:(id)sender {
    if (preferencesWc  == nil)
        preferencesWc = [MyPreferencesWindowController getInstance];

    [ preferencesWc showWindow:self ];
}

This will ensure the preferences window is only created once. And then each call to getInstance will return the same instance of the window.

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