Block 使用技巧

- (void)loadTest:(NSString *)loadFunc sucess:(void(^)(NSString *))sucess failure:(void(^)(NSString *))failure
{
    NSLog(@"11111111Test Func Start");  //@2
    if (sucess) {                       //@3    //判斷sucess參數(不爲空)
        NSString *sucessString = @"Sucess String";
        NSLog(@"333333333  Run Block Sucess");
        sucess(sucessString);       //@3-1.此時跳轉到  @3-2
    }
    
    NSString *failureString = @"Failure String";
    NSLog(@"5555555555555   Run Block Failure"); //@4
    if(failure) //@5 判斷failure參數(爲空)
        failure(failureString);
}

- (void)startLoading{
    [self loadTest:@"startLoading" sucess:
    ^(NSString * loadSucess) {           //@3-2
        NSLog(@"22222222   loading sucess");

    } failure:nil
 //       ^(NSString * loadFailure) {
//        NSLog(@"44444444    loading failure");
//    }
    ];
}
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    [self startLoading];   //@1
}

輸出以下

2015-03-18 09:48:18.453 testBarItem[2326:214237] 11111111Test Func Start
2015-03-18 09:48:18.454 testBarItem[2326:214237] 333333333  Run Block Sucess
2015-03-18 09:48:18.454 testBarItem[2326:214237] 22222222   loading sucess
2015-03-18 09:48:18.454 testBarItem[2326:214237] 5555555555555   Run Block Failure

//示例：
(void)loadData{
    [self startLoading];
    if (self.isRecord) {
        [[GoodsService sharedGoodsService] loadGoodsWithGoodsId:self.gid success:^(Goods *goodsResult) {
            dispatch_async(dispatch_get_main_queue(), ^{
                self.goods = goodsResult;
                if (self.goods) {
                   [self initContentView];
                }
                [self stopLoading];
            });
            
        } failure:^(NSError *error) {
            [self stopLoading];
            [self showError:error];
            
        }];
}


- (void)loadGoodsWithGoodsId:(LLInt)gid success:(void (^)(Goods *))success failure:(void (^)(NSError *))failure{
    NSDictionary *param = @{
                            @"goodsId":@(gid)};
    [[TcpService sharedTcpService] requestWithCmd:CMD_GOODS_ONE params:param success:^(::com::iwgame::xaction::proto::XActionResult *result) {
        if (result->rc() == 0) {
            Goods *goods = [[Goods alloc] init];
            if (result-> HasExtension(com::iwgame::msgs::proto::goods)) {
                const com::iwgame::msgs::proto::Goods& goodsPB = result->GetExtension(com::iwgame::msgs::proto::goods);
                
                 goods = [self buildGoodsWithGoodsPB:goodsPB];
            }
            
            if (success) {
                success(goods);
            }
        }else{
            failure(NE(result->rc()));
        }
    } failure:^(NSError *error) {
        if (failure) {
            failure(error);
        }
    }];
}