设置 NavigationItem 的 alpha 值
我尝试设置 navigationItem 的 alpha 值来为 rightBarbutton 设置动画，但我无法更改该值。有什么建议吗？
self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc]
initWithTitle:@"Avbryt"
style:UIBarButtonItemStyleBordered
target:self action:@selector(cancelEditing)] autorelease];
self.navigationItem.rightBarButtonItem.customView.alpha = 0.5;
I try to set the alpha value of a navigationItem to animate the rightBarbutton, but I can´t get it change the value. Any suggestions?
self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc]
initWithTitle:@"Avbryt"
style:UIBarButtonItemStyleBordered
target:self action:@selector(cancelEditing)] autorelease];
self.navigationItem.rightBarButtonItem.customView.alpha = 0.5;
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在您的代码中，您尝试为 rightBarButtonItem 的
customView设置alpha，但您的 rightBarButton 项目不包含任何自定义视图。不是吗？UIBarButtonItem项是UIBarItem的直接子类，而UIBarItem又是NSObject的子类。因此，无法直接设置其alpha。您对customView设置alpha的看法是正确的，但您错过了添加 customView 本身；-)In your code you are trying to set
alphafor the rightBarButtonItem'scustomView, but you your rightBarButton item doesn't contain any custom view. Isn't it?UIBarButtonItemitem is a direct subclass ofUIBarItemwhich in turn is a subclass ofNSObject. So, it is not possible to set itsalphadirectly. You are correct about settingalphafor thecustomView, but you have missed to add the customView itself ;-)