IOS页面组件化、解耦（CTMediator）

作者: 海牛骑士 | 来源:发表于2018-12-07 17:44 被阅读50次

日常开发中我们经常遇到不同模块之间需要进行页面的跳转。我们常规的做法就是import 我们需要跳转页面的头文件然后实例化进行跳转。如果同一个页面需要使用多次我们就得重复多次这样的操作。模块之间这样的多了之后就会造成页面高度耦合管理混乱。

通过casa的iOS应用架构谈组件化方案了解了CTMmediator 这个组件化工具

下面就用CTMmediator工具实现没有添加依赖关系的情况下实现页面的跳转。

源码 CTMmediator.h 有几个方法实例化远程APP调用入口本地组件入口释放缓存

#import <UIKit/UIKit.h>

extern NSString * const kCTMediatorParamsKeySwiftTargetModuleName;

@interface CTMediator : NSObject

+ (instancetype)sharedInstance;

// 远程App调用入口
- (id)performActionWithUrl:(NSURL *)url completion:(void(^)(NSDictionary *info))completion;
// 本地组件调用入口
- (id)performTarget:(NSString *)targetName action:(NSString *)actionName params:(NSDictionary *)params shouldCacheTarget:(BOOL)shouldCacheTarget;
- (void)releaseCachedTargetWithTargetName:(NSString *)targetName;

@end

CTMmediator.m


#import "CTMediator.h"
#import <objc/runtime.h>

NSString * const kCTMediatorParamsKeySwiftTargetModuleName = @"kCTMediatorParamsKeySwiftTargetModuleName";

@interface CTMediator ()

@property (nonatomic, strong) NSMutableDictionary *cachedTarget;

@end

@implementation CTMediator

#pragma mark - public methods
+ (instancetype)sharedInstance
{
    static CTMediator *mediator;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        mediator = [[CTMediator alloc] init];
    });
    return mediator;
}

/*
 scheme://[target]/[action]?[params]
 
 url sample:
 aaa://targetA/actionB?id=1234
 */

- (id)performActionWithUrl:(NSURL *)url completion:(void (^)(NSDictionary *))completion
{
    NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
    NSString *urlString = [url query];
    for (NSString *param in [urlString componentsSeparatedByString:@"&"])
    {
        NSArray *elts = [param componentsSeparatedByString:@"="];
        if([elts count] < 2) continue;
        [params setObject:[elts lastObject] forKey:[elts firstObject]];
    }
    
    // 这里这么写主要是出于安全考虑，防止黑客通过远程方式调用本地模块。这里的做法足以应对绝大多数场景，如果要求更加严苛，也可以做更加复杂的安全逻辑。
    NSString *actionName = [url.path stringByReplacingOccurrencesOfString:@"/" withString:@""];
    if ([actionName hasPrefix:@"native"]) {
        return @(NO);
    }
    
    // 这个demo针对URL的路由处理非常简单，就只是取对应的target名字和method名字，但这已经足以应对绝大部份需求。如果需要拓展，可以在这个方法调用之前加入完整的路由逻辑
    id result = [self performTarget:url.host action:actionName params:params shouldCacheTarget:NO];
    if (completion) {
        if (result) {
            completion(@{@"result":result});
        } else {
            completion(nil);
        }
    }
    return result;
}

- (id)performTarget:(NSString *)targetName action:(NSString *)actionName params:(NSDictionary *)params shouldCacheTarget:(BOOL)shouldCacheTarget
{
    NSString *swiftModuleName = params[kCTMediatorParamsKeySwiftTargetModuleName];
    
    // generate target
    NSString *targetClassString = nil;
    if (swiftModuleName.length > 0) {
        targetClassString = [NSString stringWithFormat:@"%@.Target_%@", swiftModuleName, targetName];
    } else {
        targetClassString = [NSString stringWithFormat:@"Target_%@", targetName];
    }
    NSObject *target = self.cachedTarget[targetClassString];
    if (target == nil) {
        Class targetClass = NSClassFromString(targetClassString);
        target = [[targetClass alloc] init];
    }
    
    // generate action
    NSString *actionString = [NSString stringWithFormat:@"Action_%@:", actionName];
    SEL action = NSSelectorFromString(actionString);
    
    if (target == nil) {
        // 这里是处理无响应请求的地方之一，这个demo做得比较简单，如果没有可以响应的target，就直接return了。实际开发过程中是可以事先给一个固定的target专门用于在这个时候顶上，然后处理这种请求的
        [self NoTargetActionResponseWithTargetString:targetClassString selectorString:actionString originParams:params];
        return nil;
    }
    
    if (shouldCacheTarget) {
        self.cachedTarget[targetClassString] = target;
    }

    if ([target respondsToSelector:action]) {
        return [self safePerformAction:action target:target params:params];
    } else {
        // 这里是处理无响应请求的地方，如果无响应，则尝试调用对应target的notFound方法统一处理
        SEL action = NSSelectorFromString(@"notFound:");
        if ([target respondsToSelector:action]) {
            return [self safePerformAction:action target:target params:params];
        } else {
            // 这里也是处理无响应请求的地方，在notFound都没有的时候，这个demo是直接return了。实际开发过程中，可以用前面提到的固定的target顶上的。
            [self NoTargetActionResponseWithTargetString:targetClassString selectorString:actionString originParams:params];
            [self.cachedTarget removeObjectForKey:targetClassString];
            return nil;
        }
    }
}

- (void)releaseCachedTargetWithTargetName:(NSString *)targetName
{
    NSString *targetClassString = [NSString stringWithFormat:@"Target_%@", targetName];
    [self.cachedTarget removeObjectForKey:targetClassString];
}

#pragma mark - private methods
- (void)NoTargetActionResponseWithTargetString:(NSString *)targetString selectorString:(NSString *)selectorString originParams:(NSDictionary *)originParams
{
    SEL action = NSSelectorFromString(@"Action_response:");
    NSObject *target = [[NSClassFromString(@"Target_NoTargetAction") alloc] init];
    
    NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
    params[@"originParams"] = originParams;
    params[@"targetString"] = targetString;
    params[@"selectorString"] = selectorString;
    
    [self safePerformAction:action target:target params:params];
}

- (id)safePerformAction:(SEL)action target:(NSObject *)target params:(NSDictionary *)params
{
    NSMethodSignature* methodSig = [target methodSignatureForSelector:action];
    if(methodSig == nil) {
        return nil;
    }
    const char* retType = [methodSig methodReturnType];

    if (strcmp(retType, @encode(void)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        return nil;
    }

    if (strcmp(retType, @encode(NSInteger)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        NSInteger result = 0;
        [invocation getReturnValue:&result];
        return @(result);
    }

    if (strcmp(retType, @encode(BOOL)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        BOOL result = 0;
        [invocation getReturnValue:&result];
        return @(result);
    }

    if (strcmp(retType, @encode(CGFloat)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        CGFloat result = 0;
        [invocation getReturnValue:&result];
        return @(result);
    }

    if (strcmp(retType, @encode(NSUInteger)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        NSUInteger result = 0;
        [invocation getReturnValue:&result];
        return @(result);
    }

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
    return [target performSelector:action withObject:params];
#pragma clang diagnostic pop
}

#pragma mark - getters and setters
- (NSMutableDictionary *)cachedTarget
{
    if (_cachedTarget == nil) {
        _cachedTarget = [[NSMutableDictionary alloc] init];
    }
    return _cachedTarget;
}

根据本地化组件接口进行跳转也非常的简单创建一个Target_page 类抛出我们的控制器

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface Target_page : NSObject
//项目组件接口
-(UIViewController *)Action_TagetViewController:(NSDictionary *)params;

@end
#import "Target_page.h"
#import <UIKit/UIKit.h>
#import "TagetViewController.h"
@implementation Target_page
-(UIViewController *)Action_TagetViewController:(NSDictionary *)params
{
    
    TagetViewController * view = [[TagetViewController alloc]init];
    //根据需求是否进行数据传递
    
    return  view;
    
}
@end

创建一个CTMmediator分类 CTMediator+NewsActions 这里面就是通过我们的中间层CTMmediator 去获取我们的控制器

#import "CTMediator.h"
#import <UIKit/UIKit.h>

@interface CTMediator (NewsActions)

-(UIViewController *)show_TagetViewControllerDetails:(NSDictionary *)dict;


@end


#import "CTMediator+NewsActions.h"


NSString * const kCTMediatorTargetnews = @"page";

NSString * const kCTMediatorActionTagetViewController = @"TagetViewController";

@implementation CTMediator (NewsActions)

-(UIViewController *)Action_TagetViewController:(NSDictionary *)dict
{
    UIViewController  * viewController =  [self performTarget:kCTMediatorTargetnews action:kCTMediatorActionTagetViewController params:@{@"key":@"value"} shouldCacheTarget:NO];
    
    if ([viewController isKindOfClass:[UIViewController class]])
    {
        return viewController;
    }
    else
    {
        
         //carsh 处理
        return  nil;
    }
   
}
@end

获取对象实现跳转这样页面间没有import 没有管理实现了跳转达到了页面解藕的目的

     UIViewController   * controller =  [[CTMediator sharedInstance] show_TagetViewControllerDetails:nil];
      [self.navigationController pushViewController:controller animated:YES];

在上面实现的过程中主要调用了 - (id)performTarget:(NSString *)targetName action:(NSString *)actionName params:(NSDictionary *)params shouldCacheTarget:(BOOL)shouldCacheTarget

注意需要传递几个参数

taegetName 抛出对象类的名称只需要传递Target_后面的部分
actionName 控制器名称
params 跳转需要的参数
shouldCacheTarget 是否缓存方便经常使用

点进实现查看主要是通过runtime 消息转发动态解析去实现

首先通过runtime NSClassFromString（）去找到我们抛出的类 Target_xxxx;


   NSString *swiftModuleName = params[kCTMediatorParamsKeySwiftTargetModuleName];
    
    // generate target
    NSString *targetClassString = nil;
    if (swiftModuleName.length > 0) {
        targetClassString = [NSString stringWithFormat:@"%@.Target_%@", swiftModuleName, targetName];
    } else {
        targetClassString = [NSString stringWithFormat:@"Target_%@", targetName];
    }
    NSObject *target = self.cachedTarget[targetClassString];
    if (target == nil) {
        Class targetClass = NSClassFromString(targetClassString);
        target = [[targetClass alloc] init];
    }

通过 runtime NSSelectorFromString（）去找到我们类里面的实现方法

   NSString *actionString = [NSString stringWithFormat:@"Action_%@:", actionName];
    SEL action = NSSelectorFromString(actionString);

然后通过消息转发去响应并返回我们创建的实例

- (id)safePerformAction:(SEL)action target:(NSObject *)target params:(NSDictionary *)params
{
    NSMethodSignature* methodSig = [target methodSignatureForSelector:action];
    if(methodSig == nil) {
        return nil;
    }
    const char* retType = [methodSig methodReturnType];

    if (strcmp(retType, @encode(void)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        return nil;
    }

    if (strcmp(retType, @encode(NSInteger)) == 0) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSig];
        [invocation setArgument:&params atIndex:2];
        [invocation setSelector:action];
        [invocation setTarget:target];
        [invocation invoke];
        NSInteger result = 0;
        [invocation getReturnValue:&result];
        return @(result);
    }

IOS页面组件化、解耦（CTMediator）

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