Question

我有两个A和B班。在A班我使用：

@interface A : B

在B班，我有这行代码：

self.navigationItem.rightBarButtonItem = [UIBarButtonItem barItemWithImage:[UIImage imageNamed:@"Add-button-normal"]
                                                          highlightedImage:[UIImage imageNamed:@"Add-button-active"]
                                                                    target:self
                                                                    action:@selector(showPopoverUI:)];

如何在A类中访问这些项目，我尝试这行代码，但它不起作用：

self.navigationItem.rightBarButtonItem = [UIBarButtonItem barItemWithImage:[UIImage imageNamed:@"Add-button-normal"]
                                                          highlightedImage:[UIImage imageNamed:@"Add-button-active"]
                                                                    target:self.parentViewController
                                                                    action:@selector(showPopoverUI:)];

我收到了这个错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[B showPopoverUI:]: unrecognized selector sent to class 0x226308'

Answer 1

如果您想调用super类方法，则需要致电super

而不是这个，你需要拨打super navigationItem...

或，

self.navigationItem.rightBarButtonItem = [UIBarButtonItem barItemWithImage:[UIImage imageNamed:@"Add-button-normal"]
                                                          highlightedImage:[UIImage imageNamed:@"Add-button-active"]
                                                                    target:self
                                                                    action:@selector(showPopoverUI:)];

Answer 2

如果你继承你应该只能使用self并调用方法就好像它是你自己的

尝试：

self.navigationItem.rightBarButtonItem = [UIBarButtonItem barItemWithImage:[UIImage imageNamed:@"Add-button-normal"] highlightedImage:[UIImage imageNamed:@"Add-button-active"]target:self action:@selector(showPopoverUI:)];

Answer 3

您在第二个示例中定位了parentViewController，而不是继续定位self。

从继承类调用方法

3 个答案: