iOS 执行完block代码块再执行下一步

//创建一个信号量（值为0）

dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

[[AFNetWorkTool shareNetWorkTool] getWarningListwithPage2:[NSString stringWithFormat:@"1"] andFinishBlock:^(id object){

NSLog(@"1");

dispatch_semaphore_signal(semaphore);

}];

//信号量减1，如果>0，则向下执行，否则等待

dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

NSLog(@"222");