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iOS push到navigation中已存在的viewCont

iOS push到navigation中已存在的viewCont

作者: Rex_ | 来源:发表于2019-08-29 17:47 被阅读0次

    前言

    对于IM页面开发中,经常会碰到跳转到一个UINavigationController的子控制器栈堆中已经存在的ViewController的情况。
    出现步骤:

    eg1- ab ab 循环

    1. 进入IM聊天,
    2. 点击头像,
    3. 点击聊天,

    eg2- abc abc循环

    1. 进入IM聊天,
    2. 点击右上角进入设置,
    3. 点击头像或者搜索聊天记录,
    4. 点击聊天

    这种情况其实微信中也处理的不是特别好:群聊中点击某个人,发起聊天后,会退回root,然后再push到与这个人的会话中。
    一般我们会认为相同的对象才会没有存在的价值,而和某人的P2P聊天与之前的Team聊天是完全不同的内容。假如是我还想与群内别人交涉,就要重新找到这个群再进行额外频繁操作了。
    基于这个设想,我认为减少出现相同控制器的过程,应该对控制器的唯一属性也进行一个确认相同操作。

    实现思路

    1. 跳转前对需要去冗的ViewController设置待判断的key-values,
    2. 对UINavigationController的pushViewController:animated:进行方法替换:跳转前发现栈堆中有相同Class时,对两个ViewController的key-values对应确认。
    3. 如果key-values相同,则用方法popToViewController:animated:跳转回到已经存在的ViewController,否则就进行正常push操作。

    实现代码

    1. UIViewController 分类
    添加操作方法和对比属性,不设置的界面则不受影响。

    @interface UIViewController (SameControllerInStack)
    
    @property (nonatomic, strong) NSDictionary * sameConfirmPropertys;
    
    - (void)gobackIfAlreadyInStackConfirmBy:(NSDictionary *)propertys;
    
    @end
    
    const void *const kSameConfirmPropertys = &kSameConfirmPropertys;
    
    @implementation UIViewController (SameControllerInStack)
    
    - (NSDictionary *)sameConfirmPropertys {
        return objc_getAssociatedObject(self, &kSameConfirmPropertys);
    }
    
    - (void)setSameConfirmPropertys:(NSDictionary *)sameConfirmPropertys {
        objc_setAssociatedObject(self, kSameConfirmPropertys, sameConfirmPropertys, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
    
    - (void)gobackIfAlreadyInStackConfirmBy:(NSDictionary *)propertys {
        self.sameConfirmPropertys = propertys;
    }
    
    @end
    

    2. UINavigationController 分类
    push方法替换,在方法中进行同属性控制器的判断

    @interface UINavigationController (SameControllerInStack)
    
    @end
    
    @implementation UINavigationController (SameControllerInStack)
    
    + (void)load {
       static dispatch_once_t onceToken;
       dispatch_once(&onceToken, ^{
           @autoreleasepool {
               [self swizzleMethod:@selector(pushViewController:animated:) swizzledSelector:@selector(swizzle_pushViewController:animated:)];
           }
       });
    }
    
    - (void)swizzle_pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
       NSDictionary * confirmPropertys = viewController.sameConfirmPropertys;
       BOOL isSame;
       if (confirmPropertys.count) {
           for (UIViewController * vc in self.viewControllers) {
               if ([vc isKindOfClass:viewController.class]) {
                   BOOL isSame = [self samePropertyOfVC1:vc VC2:viewController propertys:confirmPropertys];
                   if (isSame) {
                       [self popToViewController:vc animated:animated];
                       return;
                   }
               }
           }
       }
       [self swizzle_pushViewController:viewController animated:animated];
    }
    
    - (BOOL)samePropertyOfVC1:(id)vc1 VC2:(id)vc2 propertys:(NSDictionary *)propertys {
       for (NSString * property in propertys) {
           id object1 = [vc1 valueForKey:property];
           id object2 = [vc2 valueForKey:property];
           if (![object1 isEqual:object2]) {
               return NO;
           }
       }
       return YES;
    }
    
    

    3. NSObject 分类
    进行方法替换需要的简化方法

    
    @interface NSObject (SwizzleMethod)
    
    - (void)swizzleMethod:(SEL)originalSelector swizzledSelector:(SEL)swizzledSelector;
    
    @end
    
    @implementation NSObject (SwizzleMethod)
    
    - (void)swizzleMethod:(SEL)originalSelector swizzledSelector:(SEL)swizzledSelector {
        Class class = [self class];
        Method originalMethod = class_getInstanceMethod(class, originalSelector);
        Method swizzledMethod = class_getInstanceMethod(class, swizzledSelector);
        
        BOOL didAddMethod = class_addMethod(class,
                                            originalSelector,
                                            method_getImplementation(swizzledMethod),
                                            method_getTypeEncoding(swizzledMethod));
        if (didAddMethod) {
            class_replaceMethod(class,
                                swizzledSelector,
                                method_getImplementation(originalMethod),
                                method_getTypeEncoding(originalMethod));
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod);
        }
    }
    
    @end
    
    

    实例参考

    添加后在个人名片页面(个人信息),搜索聊天记录等可能出现重复界面的操作时,

    点击聊天.png

    根据业务需要,加上一句gobackIfAlreadyInStackConfirmBy:就可以了。

        IM_Session_MessageVC *vc = [[IM_Session_MessageVC alloc] initWithSessionId:self.userId sessionType:0];
        [vc gobackIfAlreadyInStackConfirmBy:@{@"sessionId" : self.userId,
                                              @"sessionType" : @(0), // P2P
                                              }];
        [self.navigationController pushViewController:vc animated:YES];
    

    PS

    本文只是个人见解,如果发现有问题或者有更好方案的话,请不吝赐教,共同学习进步。
    qq:12087014
    email: xingjl@outlook.com

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