FaceBook iOS SDK 批处理请求和单个完成处理程序

Question

我开始在iOS上使用Facebook SDK，我有点困惑，

我看到这一小段代码，显示了我们如何执行批处理请求，但是每个请求都有一个完成处理程序对我来说是荒谬的。当您进行单个批处理请求时，如何为每个请求创建一个完成处理程序?也许我没有理解你的意思?这肯定有一个解释，但我现在没有看到它

if ([[FBSDKAccessToken currentAccessToken] hasGranted:@"user_likes"]) {
  FBSDKGraphRequest *requestMe = [[FBSDKGraphRequest alloc]
    initWithGraphPath:@"me" parameters:nil];
  FBSDKGraphRequest *requestLikes = [[FBSDKGraphRequest alloc]
    initWithGraphPath:@"me/likes" parameters:nil];
  FBSDKGraphRequestConnection *connection = [[FBSDKGraphRequestConnection alloc] init];
  [connection addRequest:requestMe
           completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
   //TODO: process me information
}];
  [connection addRequest:requestLikes
            completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
    //TODO: process like information
  }];
  [connection start];
}

如果这是唯一的方法，我怎么能知道当我所有的请求已经执行?

Answer 1

我创建了一个FBBatchHandler类来自动组合结果并向调用者返回单个完成处理程序。下面是源代码和示例用法。它目前是专门为检索事件而设计的(即最终结果是事件的NSArray)，但它应该很容易重新用于其他任务。让我知道这是否适合你。

FBBatchHandler.h

#import <Foundation/Foundation.h>
#import "FBSDKGraphRequestConnection.h"
typedef void (^BatchFinishedHandler)(NSArray *result, NSError *error);
@interface FBBatchHandler : NSObject
- (instancetype)initWithConnection:(FBSDKGraphRequestConnection *)connection
                   finishedHandler:(BatchFinishedHandler)finishHandler;
- (void)addRequestResult:(id)result;
@end

FBBatchHandler.m

#import "FBBatchHandler.h"
@interface FBBatchHandler () <FBSDKGraphRequestConnectionDelegate>
@property (nonatomic, strong) FBSDKGraphRequestConnection *connection;
@property (nonatomic, strong) BatchFinishedHandler finishHandler;
@property (nonatomic, strong) NSMutableArray *batchResults;
@end
@implementation FBBatchHandler
#pragma mark - Instance
- (instancetype)initWithConnection:(FBSDKGraphRequestConnection *)connection
                   finishedHandler:(BatchFinishedHandler)finishHandler {
    if (self = [super init]) {
        _connection = connection;
        _connection.delegate = self;
        _finishHandler = finishHandler;
        _batchResults = [NSMutableArray new];
    }
    return self;
}
#pragma mark - Public methods
- (void)addRequestResult:(id)result {
    if ([result isKindOfClass:[NSDictionary class]]) {
        [self.batchResults addObjectsFromArray:result[@"data"]];
    }
}
#pragma mark - FBSDKGraphRequestConnectionDelegate
- (void)requestConnectionDidFinishLoading:(FBSDKGraphRequestConnection *)connection {
    self.finishHandler([self.batchResults copy], nil);
}
- (void)requestConnection:(FBSDKGraphRequestConnection *)connection
         didFailWithError:(NSError *)error {
    self.finishHandler([self.batchResults copy], error);
}
@end

范例用法

- (void)retrieveEvents {
    NSDictionary *params = @{@"since": @"now", @"fields": @"id,name,description,start_time,end_time,location,picture"};
    FBSDKGraphRequest *attending = [[FBSDKGraphRequest alloc] initWithGraphPath:@"/me/events/attending" parameters:params];
    FBSDKGraphRequest *created = [[FBSDKGraphRequest alloc] initWithGraphPath:@"/me/events/created" parameters:params];
    FBSDKGraphRequest *maybe = [[FBSDKGraphRequest alloc] initWithGraphPath:@"/me/events/maybe" parameters:params];
    FBSDKGraphRequest *notReplied = [[FBSDKGraphRequest alloc] initWithGraphPath:@"/me/events/not_replied" parameters:params];
    FBSDKGraphRequestConnection *connection = [[FBSDKGraphRequestConnection alloc] init];
    FBBatchHandler *batchHandler = [[FBBatchHandler alloc] initWithConnection:connection
                                                              finishedHandler:^(NSArray *result, NSError *error) {
                                                                  // Here's the "single" completion handler
                                                          }];
    [connection addRequest:attending
         completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
             [batchHandler addRequestResult:result];
         }];
    [connection addRequest:created
         completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
             [batchHandler addRequestResult:result];
         }];
    [connection addRequest:maybe
         completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
             [batchHandler addRequestResult:result];
         }];
    [connection addRequest:notReplied
         completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
             [batchHandler addRequestResult:result];
         }];
    [connection start];
}

Answer 2

为什么不使用一个请求呢?在您的情况下，没有必要有两个。

使用像

这样的字符

/me?fields=id,name,likes