ios - 如何为所有可能的状态设置 UIBarButtonItem backgroundImage？

Question

现在我正在写这个来设置 UIBarButtonItem 的背景图像:

[[UIBarButtonItem appearance] setBackgroundImage:image forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackgroundImage:image forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackgroundImage:image forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackgroundImage:image forState:UIControlStateDisabled barMetrics:UIBarMetricsDefault];

我怎样才能把它弄干？

谢谢，尼古拉斯

Answer 1

在 C 中，您无法以任何特别方便的方式真正枚举 enum 的值；您能做的最好的事情就是将您关心的值粘贴到一个数组中并对其进行迭代。

NSUInteger controlStates[] = {UIControlStateNormal, UIControlStateHighlighted, UIControlStateSelected, UIControlStateDisabled};
NSUInteger numControlStates = 4;
for( NSUInteger i = 0; i < numControlStates; i++ ){
    [[UIBarButtonItem appearance] setBackgroundImage:image 
                                            forState:controlStates[i]
                                          barMetrics:UIBarMetricsDefault];
}