AFNetworking

基于AFNetworking封装的下载管理类

2016-11-07  本文已影响1430人  慕言的世界

从自己刚开始做项目时，一直都是用AFNetworking进行网络请求。每次涉及网络请求的时候都手写一次，写的整个人都不好不好了。特别AFNetworking升级3.0的时候真想剁了自己的手。从那以后只要是第三方的我基本都是自己做一层封装。废话不多说下面来聊聊下载类的封装。

所谓下载管理类：无非就是，在对AFNetworking封装便用的时候，在进行一次对下载工具的封装。这样的好处有以下几点：

  1. 同一个网址的数据请求只会进行一次。 例如用户对TableView的疯狂下拉刷新 数据源处理不好可能会崩溃。
  2. 控制器消失的时候取消当前数据请求。 AFNetworking进行数据请求，如果不手动取消请求的话在控制器销毁的时候此次任务还是存在的。当请求完成的时候走回调Block这就有崩溃的危险存在。当初这里理解了，当AF请求没有完成就pop的话，由于AF引用当前界面，所以当前界面不会释放。直至完成才会释放故不存在crash一说。返回只是节省用户流量罢了。
    QQsession.h中的方法
@interface QQsession : NSObject
@property (copy, nonatomic) NSString *urlStr;
- (NSURLSessionDataTask *)conenctWithstr:(NSString *)urlStr dic:(NSDictionary *)dic fromController:(UIViewController *)controller success:(void(^)(id resposeObject))success  andfalse:(void(^)(NSError *error))falseBlock;
- (NSURLSessionDataTask *)postWithstr:(NSString *)urlStr dic:(NSDictionary *)dic fromController:(UIViewController *)controller success:(void(^)(id resposeObject))success  andfalse:(void(^)(NSError *error))falseBlock;
//
- (void)cancelWithOperation:(NSURLSessionDataTask *)operation;
@end

QQsession.m中的方法

@interface QQsession ()
@end

@implementation QQsession

- (NSURLSessionDataTask *)conenctWithstr:(NSString *)urlStr dic:(NSDictionary *)dic fromController:(UIViewController *)controller success:(void(^)(id resposeObject))success  andfalse:(void(^)(NSError *error))falseBlock
{
   //没网络的情况时直接返回

    if (![self requestBeforeJudgeConnect]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"QQtableview" object:nil];
        [[QQNetManager defaultManager] showProgressHUDWithType:0];
        return nil;
    }
    NSMutableDictionary *tokenDic = [NSMutableDictionary dictionaryWithDictionary:dic];
    [tokenDic setValue:[[NSUserDefaults standardUserDefaults] objectForKey:@"token"] forKey:@"token"];
    
    [[QQNetManager defaultManager] insertQQConnection:self];
    [controller.view Loading_0314];
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    manager.requestSerializer.timeoutInterval = 30.f;
    manager.responseSerializer = [AFJSONResponseSerializer serializer];
    manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"application/json", @"text/json", @"text/javascript", @"text/html", nil];
    NSString *encoded = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSURLSessionDataTask * operation = [manager GET:encoded parameters:tokenDic progress:^(NSProgress * _Nonnull downloadProgress) {
        
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        
        [self handleResponseObject:responseObject Controller:controller Success:success];
        
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        [self handleResponseObject:error Controller:controller failure:falseBlock];
    }];
    [[QQNetManager defaultManager] insertConnectionVC:controller QQConnection:self SessionDataTask:operation];

    return operation;
}
- (NSURLSessionDataTask *)postWithstr:(NSString *)urlStr dic:(NSDictionary *)dic fromController:(UIViewController *)controller success:(void(^)(id resposeObject))success  andfalse:(void(^)(NSError *error))falseBlock
{
    //没网络的情况时直接返回
    if (![self requestBeforeJudgeConnect]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"QQtableview" object:nil];
        [[QQNetManager defaultManager] showProgressHUDWithType:0];
        return nil;
    }
    NSMutableDictionary *tokenDic = [NSMutableDictionary dictionaryWithDictionary:dic];
    [tokenDic setValue:[[NSUserDefaults standardUserDefaults] objectForKey:@"token"] forKey:@"token"];
    
    [[QQNetManager defaultManager] insertQQConnection:self];
    [controller.view Loading_0314];
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    manager.requestSerializer.timeoutInterval = 30.f;
    manager.responseSerializer = [AFJSONResponseSerializer serializer];
    manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"application/json", @"text/json", @"text/javascript", @"text/html", nil];
    NSString *encoded = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    
   NSURLSessionDataTask * operation = [manager POST:encoded parameters:tokenDic progress:^(NSProgress * _Nonnull uploadProgress) {
        
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        [self handleResponseObject:responseObject Controller:controller Success:success];
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        [self handleResponseObject:error Controller:controller failure:falseBlock];
    }];
    [[QQNetManager defaultManager] insertConnectionVC:controller QQConnection:self SessionDataTask:operation];

    return operation;
}
#pragma mark - 统一处理下载返回的数据
- (void)handleResponseObject:(id)responseObject  Controller:(UIViewController *)controller Success:(void(^)( id  _Nullable responseObject))successBlock;
{
 

            [[NSNotificationCenter defaultCenter] postNotificationName:@"QQtableview" object:nil];
        }
  
            successBlock(responseObject);

    [UIApplication sharedApplication].networkActivityIndicatorVisible =NO;
    [[QQNetManager defaultManager] deleteQQConnection:self];
}
- (void)handleResponseObject:(NSError *)error  Controller:(UIViewController *)controller failure:(void(^)(NSError *error))failureBlock
{
    failureBlock(error);
    [controller.view Hidden];
#warning 主动退出怎么才能不显示失败的提示 -999就是取消此次下载
    if (error.code != -999) {
        //非主动取消链接
        [[QQNetManager defaultManager] showProgressHUDWithType:0];
    }
    [UIApplication sharedApplication].networkActivityIndicatorVisible =NO;
    [[QQNetManager defaultManager] deleteQQConnection:self];
}
#pragma mark - 取消下载
- (void)cancelWithOperation:(NSURLSessionDataTask *)operation
{
    [operation cancel];
    [[QQNetManager defaultManager] deleteQQConnection:self];
}
#pragma mark  网络判断
-(BOOL)requestBeforeJudgeConnect
{
    struct sockaddr zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sa_len = sizeof(zeroAddress);
    zeroAddress.sa_family = AF_INET;
    SCNetworkReachabilityRef defaultRouteReachability =
    SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
    SCNetworkReachabilityFlags flags;
    BOOL didRetrieveFlags =
    SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
    CFRelease(defaultRouteReachability);
    if (!didRetrieveFlags) {
        QMLog(@"Error. Count not recover network reachability flags\n");
        return NO;
    }
    BOOL isReachable = flags & kSCNetworkFlagsReachable;
    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
    BOOL isNetworkEnable  =(isReachable && !needsConnection) ? YES : NO;
    dispatch_async(dispatch_get_main_queue(), ^{
        [UIApplication sharedApplication].networkActivityIndicatorVisible =isNetworkEnable;/*  网络指示器的状态： 有网络 ： 开  没有网络： 关  */
    });
    return isNetworkEnable;
}

QQNetManager.h中的方法

@interface QQNetManager : NSObject
{
    NSMutableDictionary *_dataDic;///<纪录下载的url
    NSMutableArray      *_VCS; ///<纪录当前控制器有哪些下载
    UIAlertView         * _alert;///<防治alert重复出现
}
+ (id)defaultManager;

- (NSURLSessionDataTask *)startGetHttpWithStr:(NSString *)url Dictionary:(NSDictionary *)parameters  fromController:(UIViewController *)controller Success:(void(^)( id responseObject))Success andFalse:(void(^)(NSError *error))falseBlock;
- (NSURLSessionDataTask *)startPostHttpWithStr:(NSString *)url  Dictionary:(NSDictionary *)parameters  fromController:(UIViewController *)controller Success:(void(^)( id responseObject))Success andFalse:(void(^)(NSError *error))falseBlock;
- (void)insertQQConnection:(QQsession *)hc;///<插入对象
- (void)deleteQQConnection:(QQsession *)hc;//<删除对象
//- (void)stopAllConnection;
- (void)showProgressHUDWithType:(NSInteger)type;//<显示提示
//控制器用
- (void)insertConnectionVC:(UIViewController *)VC  QQConnection:(QQsession *)hc  SessionDataTask:(NSURLSessionDataTask *)task;//<插入但前控制器的

- (void)deleteConnectionVC:(UIViewController *)vc;//<销毁控制器诗取消下载```
`QQNetManager.m`中的方法

@implementation QQNetManager
{
NSURLSessionDataTask * operation;
NSLock *lock;
}

如果，在线程A 调用unlock方法之前，另一个线程B调用了同一锁对象的lock方法。那么，线程B只有等待。直到线程A调用了unlock
*/

warning 这里主要还是根据入库的控制器来写不是一定的 根据个人需要

// //针对滑动的三方
for (UIViewController *VC in VCArray) {
for (NSDictionary *TempDic in tempArr) {
if (TempDic[String(VC)]) {
[self deleteQQConnection:TempDic[String(VC)]];
[(QQsession *)TempDic[String(VC)] cancelWithOperation:TempDic[@"Task"]];
if (_IsConsolePrint) {
QMLog(@"Cancel this url '%@'",[(QQsession *)TempDic[String(VC)] urlStr]);
}
[_VCS removeObject:TempDic];
}
}
}
[lock unlock];
});
}

下面是自定义Navgationcontroller配合下载类做控制器销毁取消下载
`QQNavigationController.m`文件中的方法

@interface QQNavigationController ()<UIGestureRecognizerDelegate,UINavigationControllerDelegate>
{
UIViewController *tempVC;///栈顶的控制器
}
@end

@implementation QQNavigationController

}

// [[UINavigationBar appearance] setBackgroundImage:[UIImage new]
// forBarPosition:UIBarPositionTop
// barMetrics:UIBarMetricsDefault];
//设置navi透明需要translucent = yes,设置图片，barMetrics（更改类型的道不同的效果）
}else{
// [self.navigationBar setBackgroundImage:[UIImage new]
// forBarMetrics:UIBarMetricsDefault];
}
//nav下面的横线消失
// self.navigationBar.shadowImage = [UIImage new];

}
//配合修改状态栏颜色

warning 这里可以设置返回手势的开关

//推送的视图将要出现时将侧滑返回设置为真

文件中的注释已经很详细了，在这里就不多做赘述了。
有个要注意的是`AFNetworking` 手动取消下载也会执行下载失败的回调，打印`error`为
```Error Domain=NSURLErrorDomain Code=-999 "已取消" UserInfo={NSErrorFailingURLKey=http://172.16.10.34:8080/wisdomCampus_interface/assessment/queryList?flag=1&pageindex=1&pagesize=10&token=932b80a56a38bcc1b22796c2fdf57383, NSLocalizedDescription=已取消, NSErrorFailingURLStringKey=http://172.16.10.34:8080/wisdomCampus_interface/assessment/queryList?flag=1&pageindex=1&pagesize=10&token=932b80a56a38bcc1b22796c2fdf57383}```
可以利用`error ==-999`来判断是不是取消下载执行的失败回调。

##2016.11.14日更新内容
之前的
```UIViewController * VC =   [self popViewControllerAnimated:YES];
//这里打印的是刚刚出栈的VC 
    QMLog(@"%@",VC);
    [[QQNetManager defaultManager] deleteConnectionVC:VC]```
会有一个问题  就是当我A界面push进B界面，然后迅速（就是很快很快）pop回B界面，虽然返回成功但是`popViewControllerAnimated:YES` 的返回值是`nil`之前在`- (void)deleteConnectionVC:(UIViewController *)vc
`里面没有做空的判断因此会崩溃。不过此时`viewControllers`里面是有B界面的。所以现在用`    [[QQNetManager defaultManager] deleteConnectionVC:self.viewControllers.lastObject];
`来取值
##2017.03.18日更新内容
`popViewControllerAnimated:YES `返回为nil，大概是因为pop动画没有完成的造成的。与之相关联的章[我是传送门点我进入](http://blog.lessfun.com/blog/2015/09/09/uiviewcontroller-push-pop-trap/)
[附上下载地址](http://code.cocoachina.com/view/134516)demo里面有增加一些东西文章中没有写出来
[自己日常用到的一些组件](https://github.com/MuYanQin/QQKit)

#如有错误请提出我会改正，勿喷！持续更新。。
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