在从SQLiteDB中删除之前等待API响应-WaitingonAPIresponsebeforedeletingfromSQLiteDB

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Use an operation queue and your own custom operation. Setup the operation queue to be serial or set it to allow some small number of concurrent operations.

使用操作队列和您自己的自定义操作。将操作队列设置为串行或将其设置为允许少量并发操作。

Loop through each record creating an operation for each record. Put each operation on the queue.

遍历每条记录，为每条记录创建一个操作。将每个操作放在队列中。

The implementation of the operation will be to make the API call and then delete the one record if that API call indicates it should be deleted. Ensure that the operation's main doesn't reach its end until the API call is complete.

该操作的实现将是进行API调用，然后如果该API调用指示应删除该记录，则删除该记录。确保在API调用完成之前，操作的main不会到达终点。

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Create an array where you will hold temporarily your data to delete

创建一个数组，暂时保存要删除的数据

NSMutableArray* itemsToDelete = [[NSMutableArray alloc] init] 

Once you received a response with success you append the items to be deleted to this array. do the same process in all calls with success. once your done with uploading your data at your last response of success or failure check your itemsToDelete array inside a for loop and delete everything from your DB

收到成功的响应后，将要删除的项目附加到此数组。在所有呼叫中成功执行相同的过程。完成上次成功或失败响应后上传数据后，检查for循环中的itemsToDelete数组并删除数据库中的所有内容

0  

I suggest using blocks to receive the response from async calls. In that case, you can perform the DB operation within the block.

我建议使用块来接收来自异步调用的响应。在这种情况下，您可以在块中执行DB操作。

dispatch_async(dispatch_get_main_queue()); is not for the async calls. It is mostly used to update the UI.

dispatch_async（dispatch_get_main_queue（））;不适用于异步调用。它主要用于更新UI。

All the async calls needs to be done on background thread.

所有异步调用都需要在后台线程上完成。

Coming to your problem, you can do something like this:

来你的问题，你可以做这样的事情：

-(void)checkToDeleteWithCompletion:(MyCompletion)completion{

    __block NSMutableArray *respOnseArray=  [NSMutableArray array];

  // Create a dispatch group
    dispatch_group_t group = dispatch_group_create();

    for (int i = 0; i 

dispatch_semaphore_create(maxConcurrencyValue)