Xcode 11.4 和 iOS 13.4 打破了项目中的 Objective-C 类别

Question

I have a project which the code base is in Objective-C. Ever since iOS 13, due to the changes in modalPresentationStyle, the app got changed into the new behaviour of modalStyles. Due to the requirements of the company and the client, the modalPresentationStyle should remain in fullscreen.

To fix this a couple months ago we created an Objective-C Category file which extends the functionality of UIViewController. In this class we implemented two methods to be inherited into every vc in the project:

- (UIModalPresentationStyle)modalPresentationStyle
{
    return UIModalPresentationFullScreen;
}

- (UIStatusBarStyle)preferredStatusBarStyle
{
    return UIStatusBarStyleLightContent;
}

By adding this two methods to the ObjC category let us add this configuration only once, in this file, and it replicates automatically into the VCs. We didn't want to write this methods in every vc, it are only written if an exception needs to be added.

This worked for us in the versions leading up to this weeks update.

After Xcode and iOS got updated, to 11.4 and 13.4 respectively the behaviour of this category broke. Now this methods are not automatically called by the viewcontrollers when they are instantiated.

I don't know if it is related to the an entry of the release notes which states:

"Creating an Objective-C category file by choosing File > New > File no longer creates a file that includes an import of the AppKit framework. (55977950) (FB7346800)"

This broke a lot of projects that need to be updated in the coming days.

Answer 1

I had the same problem，using class_replaceMethod can solve the problem. If the xcode version of your release is not 11.4 then this is not a problem:

[self swizzleInstanceSelector:NSSelectorFromString(@"modalPresentationStyle") withSelector:@selector(uiviewController_modalPresentationStyle)];

- (UIModalPresentationStyle)uiviewController_modalPresentationStyle {
    return UIModalPresentationFullScreen;
}