UIToolBar-禁用按钮 [英] UIToolBar - disable buttons

问题描述

在我的应用程序中，我有一个工具栏，在某个时候我想禁用或启用某些按钮.这样做最简单的方法是什么?如何访问UIToolbar的items属性?

in my app I have a toolbar and at a certain point I want to disable or enable some buttons. What is the easiest way to do so? How can I access items property of UIToolbar?

这是我的代码:

-(void)addToolbar {
    NSMutableArray *buttons = [[NSMutableArray alloc] init]; 

    //Define space
    UIBarButtonItem *flexibleSpaceItem; 
    flexibleSpaceItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem: UIBarButtonSystemItemFlexibleSpace target:nil action:NULL]; 

    //Add "new" button
    UIBarButtonItem *newButton = [[UIBarButtonItem alloc]
                                  initWithTitle:@"New" style:UIBarButtonItemStyleBordered target:self action:@selector(new_clicked)];
    [buttons addObject:newButton];
    [newButton release];

    //Add space
    [buttons addObject:flexibleSpaceItem];

    //Add "make active" button
    UIBarButtonItem *activeButton = [[UIBarButtonItem alloc]
                                  initWithTitle:@"Make Active" style:UIBarButtonItemStyleBordered target:self action:@selector(make_active_clicked)];
    [buttons addObject:activeButton];
    [activeButton release];

    [buttons addObject:flexibleSpaceItem];

    //Add "edit" button
    UIBarButtonItem *editButton = [[UIBarButtonItem alloc]
                                  initWithTitle:@"Edit" style:UIBarButtonItemStyleBordered target:self action:@selector(edit_clicked)];
    [buttons addObject:editButton];
    [editButton release];

    [flexibleSpaceItem release];

    [toolBar setItems:buttons];
    [buttons release];
}

谢谢.

推荐答案

最简单的方法是将对UIBarButtonItem的引用保存为实例变量.

The simplest way is to save a reference to the UIBarButtonItem as an instance variable.

# header file
UIBarButtonItem *editButton;

然后您的代码变为

# .m file
editButton = [[UIBarButtonItem alloc]
               initWithTitle:@"Edit"
               style:UIBarButtonItemStyleBordered
               target:self
               action:@selector(edit_clicked)];
[buttons addObject:editbutton];

现在在任何实例方法中的任何地方，禁用按钮都非常简单:

Now anywhere in any instance method, disabling the button is as simple as:

editButton.enabled = NO;

也不要立即release它，因为该类现在拥有按钮对象.因此，在dealloc方法中将其替换为release.

Also dont release it immediately, since this class now owns the button object. So release it in the dealloc method instead.

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