UIToolBar - 禁用按钮

Question

在我的应用程序中我有一个工具栏,在某一点上我想禁用或启用一些按钮.最简单的方法是什么？如何访问UIToolbar的items属性？

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];
}

先感谢您.

Answer 1

最简单的方法是保存对UIBarButtonItem实例变量的引用.

# header file
UIBarButtonItem *editButton;

然后你的代码变成了

# .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位置,禁用按钮都非常简单:

editButton.enabled = NO;

也不要release马上,因为这个类现在拥有按钮对象.所以release它在dealloc方法中代替.

Answer 2

快速列举救援!

- (void) setToolbarButtonsEnabled:(BOOL)enabled
{
    for (UIBarButtonItem *item in self.toolbarItems)
    {
        item.enabled = !enabled;
    }
}