在主线程上运行 NSURLSession 完成处理程序 [英] Running NSURLSession completion handler on main thread
问题描述
我正在使用 NSURLSession 来获取填充 TableView 的值.我正在更新完成处理程序中的 TableView,但是使用 [[NSThread currentThread] isMainThread]
显示完成处理程序没有在主线程中运行.因为我应该只从主线程更新 UI,所以我知道这是不正确的.有没有办法从完成处理程序触发主线程上的操作?或者使用 NSURLSession 是错误的方法吗?
I am using a NSURLSession to get the values to populate a TableView. I am updating the TableView in the completion handler, but using [[NSThread currentThread] isMainThread]
has shown me that the completion handler isn't running in the main thread. Since I should only updating the UI from the main thread, I know this isn't correct. Is there a way to trigger an action on the main thread from the completion handler? Or is using a NSURLSession the wrong way to go about this?
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithURL:[NSURL URLWithString:@"http://myurl"]
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSError *jsonError = nil;
NSArray* jsonUsers = [NSJSONSerialization JSONObjectWithData:data options:0 error:&jsonError];
if (jsonError) {
NSLog(@"error is %@", [jsonError localizedDescription]);
// Handle Error and return
return;
}
self.userArray = jsonUsers;
[self.userTableView reloadData];
if ([[NSThread currentThread] isMainThread]){
NSLog(@"In main thread--completion handler");
}
else{
NSLog(@"Not in main thread--completion handler");
}
}] resume];
推荐答案
是的,只需使用 GCD
调度你的主线程:
Yes, just dispatch your main thread stuff using GCD
:
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithURL:[NSURL URLWithString:@"http://myurl"]
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSError *jsonError = nil;
NSArray* jsonUsers = [NSJSONSerialization JSONObjectWithData:data options:0 error:&jsonError];
if (jsonError) {
NSLog(@"error is %@", [jsonError localizedDescription]);
// Handle Error and return
return;
}
dispatch_async(dispatch_get_main_queue(), ^{
self.userArray = jsonUsers;
[self.userTableView reloadData];
if ([[NSThread currentThread] isMainThread]){
NSLog(@"In main thread--completion handler");
}
else{
NSLog(@"Not in main thread--completion handler");
}
});
}] resume];
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