UIButton 在 iOS 中不显示

Question

以下是在工具栏上显示按钮的代码。

UIButton myButton = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *myImage = [UIImage imageNamed:@"img1.png"];

[myButton setBackgroundImage:myImage forState:UIControlStateNormal];
UIBarButtonItem *myToolbarButton = [[UIBarButtonItem alloc] initWithCustomView:myButton];

工具栏上没有显示任何内容。请告诉我出了什么问题。

Answer 1

[myToolbar setItems:[NSArray arrayWithObject:myToolbarButton]]; // might help

或者如果它是导航栏

self.navigationItem.rightBarButtonItem = myToolbarButton;

您还应该设置自定义按钮的框架，如下所示：

UIButton *mybutton = [[UIButton alloc] initWithFrame:CGRectMake:0,0,200,50];

然后，如果您想添加选择器/回调：

[myButton addTarget:self action:@selector(someMethod) forControlEvents:UIControlEventTouchUpInside];

Answer 2

self.navigationItem.leftBarButtonItem = myButtonItem; // and change for the right button.

其中 self 是 UIViewController。

Answer 3

您忘记将此按钮添加到工具栏！

NSArray *toolbarItems = [[NSArray alloc] initWithObjects:myToolbarButton,nil]; // you can more buttons here
[aToolbar setItems:toolbarItems animated:NO]; // change to YES if you want to have nice animation
[toolbarItems release];

如果你想在导航栏添加一个按钮，请使用这个：

[self.navigationItem setRightBarButtonItem:myToolbarButton]; // or setLeft...

另外，你应该记住设置myButton的框架：

[myButton setFrame:CGRectMake(0, 0, 30, 32)];