组件化方案 阅读笔记

组件

从功能业务角度上看不能在查分,适可替换,可复用的.

模块

有多个组件组成,他可以实现一个独立的功能,一个或多个业务.

例如大众点评的美食功能是一个业务,也可以叫做"美食模块".

模块化开发 中介者

//Mediator.m 中间件代码
@implementation Mediator
+ (UIViewController *)OpenViewController1:(NSString *)viewId {
 Class cls = NSClassFromString(@"UIViewController1");
 return [cls performSelector:NSSelectorFromString(@"viewController1:") withObject:@{@"viewId": viewId}];
}
+ (UIViewController *) OpenViewController2:(NSString *) viewId type:(NSInteger)type {
 Class cls = NSClassFromString(@"UIViewController2");
 return [cls performSelector:NSSelectorFromString(@"viewController2:") withObject:@{@"viewId": viewId, @"type": @(type)}];
}
@end

//调用者
#import "Mediator.h"
@implementation ViewController
- (void)gotoViewController1 {
 UIViewController * vc = [Mediator OpenViewController1:@"id" ];
 [self.navigationController pushViewController: vc animated:YES];
}

- (void) gotoViewController2 {
 UIViewController * vc = [Mediator OpenViewController1:@"id" type:1 ];
 [self.navigationController pushViewController: vc animated:YES];
}
@end

这样在调用里面就不用引用 UIViewController1和 UIViewController1 的头文件了 就不会产生相互依赖 只要在调用其他组件的时候引入 Mediator.h 就可以了.接下来就是优化这套写法，有两个优化点：
1.Mediator 每一个方法里都要写 runtime 方法，格式是确定的，这是可以抽取出来的。
2.每个组件对外方法都要在 Mediator 写一遍，组件一多 Mediator 类的长度是恐怖的。

蘑菇街为了补全本地调用的功能，为组件多加了另一种方案，就是通过 protocol-class 注册表的方式。(感觉比上面的方案要复杂很多)
首先有一个新的中间件：

//ProtocolMediator.m 新中间件
@implementation ProtocolMediator
@property (nonatomic, storng) NSMutableDictionary *protocolCache
//注册协议协议
- (void)registerProtocol:(Protocol *)proto forClass:(Class)cls {
 NSMutableDictionary *protocolCache;
 [protocolCache setObject:cls forKey:NSStringFromProtocol(proto)];
}

- (Class)classForProtocol:(Protocol *)proto {
 return protocolCache[NSStringFromProtocol(proto)];
}
@end

然后有一个公共Protocol文件，定义了每一个组件对外提供的接口：

//ComponentProtocol.h
@protocol BookDetailComponentProtocol <NSObject>
- (UIViewController *)bookDetailController:(NSString *)bookId;
- (UIImage *)coverImageWithBookId:(NSString *)bookId;
@end

@protocol ReviewComponentProtocol <NSObject>
- (UIViewController *)ReviewController:(NSString *)bookId;
@end

再在模块里实现这些接口，并在初始化时调用 registerProtocol 注册。

//BookDetailComponent 组件
#import "ProtocolMediator.h"
#import "ComponentProtocol.h"
#import "WRBookDetailViewController.h"
+ (void)initComponent
{
 [[ProtocolMediator sharedInstance] registerProtocol:@protocol(BookDetailComponentProtocol) forClass:[self class];
}

- (UIViewController *)bookDetailController:(NSString *)bookId {
 WRBookDetailViewController *detailVC = [[WRBookDetailViewController alloc] initWithBookId:param[@"bookId"]];
 return detailVC;
}

- (UIImage *)coverImageWithBookId:(NSString *)bookId {
 ….
}

最后调用者通过 protocol 从 ProtocolMediator 拿到提供这些方法的 Class，再进行调用：

//WRReadingViewController.m 调用者
//ReadingViewController.m
#import "ProtocolMediator.h"
#import "ComponentProtocol.h"
+ (void)gotoDetail:(NSString *)bookId {
 Class cls = [[ProtocolMediator sharedInstance] classForProtocol:BookDetailComponentProtocol];
 id bookDetailComponent = [[cls alloc] init];
 UIViewController *vc = [bookDetailComponent bookDetailController:bookId];
 [[UIApplication sharedApplication].keyWindow.rootViewController.navigationController pushViewController:vc animated:YES];
}