這是從後臺線程訪問UI工具包的安全方式嗎？

Question

我不得不從服務器上下載圖片，但我不想創建NSURLConnection，我知道UIKit不是線程安全的，所以我試過了，只需要確認一下，如果這是安全的還是會導致崩潰截至目前它工作正常。）我試過以下

看看交換機的情況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

這對我來說看起來很安全。你可以在後臺線程上完成所有的網絡連接，然後只用你回叫的主線程方法觸摸UI。通常人們會使用GCD或NSOperationQueue，但這也應該起作用。

Answer 2

只要在主線程上完成實際的UI更新工作，你就會好起來的。