IOS-Runtime: shortcuts to page Jump, ios-runtime jump
Preface
During the webpage jump, if the current class is not UIViewcontroller (which is represented by VC below), will you write a proxy or block it to the VC to pass the information, and then perform
/// Assume that targetVc is the page to jump to [self. navigationController pushViewController: targetVc animated: YES];
TableViewCell is used as an example. If there are many such operations in tableViewCell displayed on each page, many proxies or blocks will be written. If not, what should we do, the idea is to obtain the VC currently displayed on the top layer. There are many methods on the Internet. First, let's look at a common method.
- (UIViewController *)currentViewController { UIWindow *keyWindow = [UIApplication sharedApplication].keyWindow; UIViewController *vc = keyWindow.rootViewController; while (vc.presentedViewController) { vc = vc.presentedViewController; if ([vc isKindOfClass:[UINavigationController class]]) { vc = [(UINavigationController *)vc visibleViewController]; } else if ([vc isKindOfClass:[UITabBarController class]]) { vc = [(UITabBarController *)vc selectedViewController]; } } return vc;}
The above method may be able to obtain the top-level VC (I found one on the Internet and did not test it. I will only compare it here), but does it feel complicated, of course, you can also write it in a tool. Every time you use this method in the tool, you can also get it, but I always feel complicated, haha;
Using Runtime
Runtime is a fun thing. In the previous article, I briefly talked about some of its common functions. Here, we use Category to obtain the current VC requirements.
1. Create a new category based on UIApplication
Click Next.
2. Use Runtime to add attributes
In the UIApplication + CurrentViewController. h file, add
/// Obtain the current UIViewController @ property (nonatomic, weak) UIViewController * currentViewController;
In the UIApplication + CurrentViewController. m file, introduce the header file
#import <objc/runtime.h>
Get set Method of attribute using runtime
///set- (void)setCurrentViewController:(UIViewController *)currentViewController{ objc_setAssociatedObject(self, @selector(currentViewController), currentViewController, OBJC_ASSOCIATION_ASSIGN);}///get- (UIViewController *)currentViewController{ return objc_getAssociatedObject(self, _cmd);}
3. Implementation
Introduce the header file in the file that needs to obtain the current VC, or directly put the header file into the macro file.
#import "UIApplication+CurrentViewController.h"
In the viewWillAppear method of VC, add
[UIApplication sharedApplication].currentViewController = self;
In this way, we can get the current VC by adding the following code. After obtaining the VC, whether it is push, present or javasmseguewithidentifier, the page can be redirected.
UIViewController *viewVc = [UIApplication sharedApplication].currentViewController;
4. Extend
The above needs to be added in every VC
[UIApplication sharedApplication].currentViewController = self;
You can create a base class BaseViewController Based on UIViewController and add the above Code in the viewWillAppear method of BaseViewController. When creating a VC, you only need to inherit the BaseViewController!