这是从后台线程访问UI工具包的安全方式吗？

Question

我不得不从服务器上下载图片，但我不想创建NSURLConnection，我知道UIKit不是线程安全的，所以我试过了，只需要确认一下，如果这是安全的还是会导致崩溃截至目前它工作正常。）我试过以下

看看交换机的情况2。

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
    switch (indexPath.row) { 
    case 0: 
    { 
     CreateNewSurveyViewController *vc=[[CreateNewSurveyViewController alloc] init]; 
     [self.navigationController pushViewController:vc animated:YES]; 
     [vc release]; 
     break; 
    } 
    case 1:{ 
     MySurveyViewController *mySurveyViewController=[[MySurveyViewController alloc] init]; 
     [self.navigationController pushViewController:mySurveyViewController animated:YES]; 
     [mySurveyViewController release]; 
     break; 
    } 
    case 2:{ 

     self.progressHud.hidden = NO; 
     [self performSelectorInBackground:@selector(loadProfileImage) withObject:nil]; 
     break; 
    } 
    default: 
     break; 
    } 
} 
-(void)loadProfileImage { 

    NSData* profileImageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:self.userAccount.profileImageURL]]; 
    [self performSelectorOnMainThread:@selector(launchSettingsView:) withObject:profileImageData waitUntilDone:YES]; 

} 

-(void)launchSettingsView:(NSData*)profileImageData { 
    self.userAccount.userImage = [UIImage imageWithData:profileImageData]; 
    self.progressHud.hidden = YES; 
    SettingsViewController* settingsViewController=[[SettingsViewController alloc] init]; 
    settingsViewController.userAccount = self.userAccount; 
    settingsViewController.delegate = self; 
    [self.navigationController pushViewController:settingsViewController animated:YES]; 
    [settingsViewController release]; 
} 

Answer 1

这对我来说看起来很安全。你可以在后台线程上完成所有的网络连接，然后只用你回叫的主线程方法触摸UI。通常人们会使用GCD或NSOperationQueue，但这也应该起作用。

Answer 2

只要在主线程上完成实际的UI更新工作，你就会好起来的。