我有一个异步的方法，如何在多次并发后得到全部结束的通知
第三方sdk有个异步上传方法 [UploadManager upload],但是只能单文件上传，要批量上传，得多次调用这个方法。现在我想得到他们全部结束的通知。
我尝试了用gcd group的方法，
dispatch_group_t group = dispatch_group_create();
for (NSData *data in array) {
dispatch_group_async(group, dispatch_get_global_queue(0,0), ^{
[UploadManager upload];
});
}
dispatch_group_notify(group, dispatch_get_global_queue(0,0), ^{
// 汇总结果
});
但是因为[UploadManager upload]是异步的，汇总结果总是一开始就先执行了。有什么办法解决吗？
6885789
10 years, 5 months ago
Answers
这个真算是月经问题了。我直接放一段代码你就懂了。
dispatch_group_t serviceGroup = dispatch_group_create();
// Start the first service
dispatch_group_enter(serviceGroup);
[self.configService startWithCompletion:^(ConfigResponse *results, NSError* error){
// Do something with the results
configError = error;
dispatch_group_leave(serviceGroup);
}];
// Start the second service
dispatch_group_enter(serviceGroup);
[self.preferenceService startWithCompletion:^(PreferenceResponse *results, NSError* error){
// Do something with the results
preferenceError = error;
dispatch_group_leave(serviceGroup);
}];
dispatch_group_notify(serviceGroup,dispatch_get_main_queue(),^{
// Assess any errors
NSError *overallError = nil;
if (configError || preferenceError)
{
// Either make a new error or assign one of them to the overall error
overallError = configError ?: preferenceError;
}
// Now call the final completion block
completion(overallError);
});
YANYAN
answered 10 years, 5 months ago