如何获取当前的控制器

梦里梦外; 2022-04-15 00:49 181阅读 0赞

## 如何获取当前的控制器 ##

--------------------

我百度了一下，都是从window的根控制器，开始一个个判断，诸如是否含有UINavigationController、UITabBarController。如果是iPad应用还要判断是否含有UISplitViewController。在这之前还得判断控制器的跳转方式。有没有更简单的方式呢

答案肯定是有了。  
废话不多说，直接上代码了。

*  创建单例对象来存储全局变量`currentController`

#import <Foundation/Foundation.h>
    @interface YHGlobleObject : NSObject
    @property (nonatomic, weak) UIViewController *currentController;
    SingletonH(Instance)
    @end
    #import "YHGlobleObject.h"
    SingletonM(Instance)
    @implementation YHGlobleObject
    @end
    //单例宏（以下代码放在你经常定义宏的.h文件中）
    #define SingletonH(name) + (instancetype)shared##name;
    #define SingletonM(name) \
    static id _instance; \
    \
     - (instancetype)allocWithZone:(struct _NSZone *)zone \
    { \
    static dispatch_once_t onceToken; \
    dispatch_once(&onceToken, ^{ \
    _instance = [super allocWithZone:zone]; \
    }); \
    return _instance; \
    } \
    \
     - (instancetype)shared##name \
    { \
    static dispatch_once_t onceToken; \
    dispatch_once(&onceToken, ^{ \
    _instance = [[self alloc] init]; \
    }); \
    return _instance; \
    } \
    \
     - (id)copyWithZone:(NSZone *)zone \
    { \
    return _instance; \
    }\
    \
     - (id)mutableCopyWithZone:(NSZone *)zone { \
    return _instance; \
    }

*  使用runtime的swizzleAPI来hook`viewWillAppear:`方法，如果你能保证当前的控制器都是你自己定义的viewController，也可以不用runtime（毕竟runtime方法作用范围广，深。消耗一定的性能的同时，滥用会造成无法预料的结果。）直接将`-(void)viewWillAppear:(BOOL)animated{ [super viewWillAppear:(BOOL)animated]; YHGloble.currentController = self; }`写在你自己定义的viewController基类的.m中，否则创建以下分类

> @implementation UIViewController (YHExtension)  
> \+(void)load\{  
> \[self swizzleInstanceMethod:@selector(viewWillAppear:) with:@selector(hook\_viewWillAppear:)\];  
> \}  
> \-(void)hook\_viewWillAppear:(BOOL)animated\{  
> \[self hook\_viewWillAppear:animated\];  
> YHGloble.currentController = self;  
> \}  
> \+(BOOL)swizzleInstanceMethod:(SEL)originalSel with:(SEL)newSel \{  
> Method originalMethod = class\_getInstanceMethod(self, originalSel);  
> Method newMethod = class\_getInstanceMethod(self, newSel);  
> if (!originalMethod || !newMethod) return NO;  
> class\_addMethod(self,  
> originalSel,  
> class\_getMethodImplementation(self, originalSel),  
> method\_getTypeEncoding(originalMethod));  
> class\_addMethod(self,  
> newSel,  
> class\_getMethodImplementation(self, newSel),  
> method\_getTypeEncoding(newMethod));  
> method\_exchangeImplementations(class\_getInstanceMethod(self, originalSel),  
> class\_getInstanceMethod(self, newSel));  
> return YES;  
> \}  
> @end

使用的时候直接使用`[YHGlobleObject sharedInstance].currentController`即可，总结一下：你也可以hook`viewDidAppear`，具体情况具体使用。