加载视图显得太慢

在我的iPhone应用程序中，我有一个更新按钮，当按下时添加一个新的子视图。这个新视图覆盖整个屏幕，并且只有在整个更新操作完成时才能访问表视图。这是实际上这个想法，但我的实现有以下问题 - 视图显得太慢，需要2或3秒才能弹出。加载视图显得太慢

我认为可能的解决方案是启动一个新线程并同步它，但我不确定这是否会有所帮助。

- (IBAction) updateButtonPressed: (id)sender { 
    self.updateButton.enabled = NO; 

    //HERE STARTS THE LOADING VIEW 
    LoadingView * loadingView =[LoadingView initializeLoadingView:[self.view.window.subviews objectAtIndex:0]]; 

    //HERE STARTS THE LOADING VIEW 
    [self deleteData];//delete old data 
    [self insertNewData]; 
    [self loadNewData]; 

    //THE LOADING VIEW IS DISMISSED 
    [loadingView dismissView]; 

    //THE LOADING VIEW IS DISMISSED 

    self.updateButton.enabled = YES; 

}// updateButtonPressed

视图必须在动作开始后立即显示，因为否则整个程序逻辑将变为地狱。

编辑：这里是这两种方法insertNewData和loadNewData

- (void) insertNewData 
    { 
     NSString *urlStr; 
     NSError *error; 
     NSURLResponse *response; 
     if(self.title == @"New York") 
     { 
      urlStr =[[NSString alloc] initWithFormat: @"http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=New_York,IL"]; 
     } 
     else 
      urlStr = [NSString stringWithFormat:@"http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=%@,IL",self.title]; 

     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: [NSURL URLWithString:urlStr]]; 
     NSData *dataReply = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; 
     xmlControl = [[XMLController alloc] loadXMLbyData:dataReply]; 
     Forecast *forecast; 

     for(ForecastPeriod *newForecast in [xmlControl weatherForecasts]) 
     { 
      forecast = [[Forecast alloc] initWithEntity:[NSEntityDescription entityForName:@"Forecast" inManagedObjectContext:self.managedObjectContext] insertIntoManagedObjectContext:self.managedObjectContext]; 
      [forecast setValue:newForecast.conditions forKey:@"conditions"]; 
      [forecast setValue:newForecast.day forKey:@"day"]; 
      [forecast setValue:newForecast.icon forKey:@"icon"]; 
      [self addImagesAtSpecificDirectory:newForecast.icon]; 
      [forecast setValue:newForecast.max forKey:@"max"]; 
      [forecast setValue:newForecast.min forKey:@"min"]; 
      [forecast setValue:newForecast.month forKey:@"month"]; 
      [forecast setValue:newForecast.period forKey:@"period"]; 
      [forecast setValue:newForecast.weekday forKey:@"weekday"]; 
      [forecast setValue:newForecast.year forKey:@"year"]; 
      [forecast setValue:self.title forKey:@"location"]; 

     } 
     if (![self.managedObjectContext save:&error]) { 
      NSLog(@"Couldn't save: %@", [error localizedDescription]);   
     } 

    }//insertNewData 


    - (void) loadNewData 
    { 
     AppDelegate *appDelegate = (AppDelegate*) [[UIApplication sharedApplication] delegate]; 
     NSManagedObjectContext *managedObjectContext = appDelegate. managedObjectContext; 
     NSFetchRequest *request = [[NSFetchRequest alloc] init]; 
     NSEntityDescription *entity = [NSEntityDescription entityForName:@"Forecast" inManagedObjectContext:managedObjectContext]; 
     [request setEntity:entity]; 
     NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"period" ascending:YES]; 
     [request setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]]; 
     NSPredicate *predicate = [NSPredicate predicateWithFormat:@"location = %@",self.title]; 
     [request setPredicate:predicate]; 
     NSError *error; 
     NSMutableArray *mutableFetchResults = [[managedObjectContext executeFetchRequest:request error:&error] mutableCopy]; 
     self.items = mutableFetchResults; 
     [self.tableView reloadData]; 
     [mutableFetchResults release]; 
     [request release]; 

     //iPad 
     if ([[UIDevice currentDevice] userInterfaceIdiom]==UIUserInterfaceIdiomPad && popOver_ != nil) 
     { 
      [popOver_ dismissPopoverAnimated:YES]; 
     } 


    }//loadNewData

来源

2011-12-19 e2l3n

loadNewData是做什么的？给我们那个代码。 – vikingosegundo 2011-12-19 11:17:36

我想我只是找到了问题，它真的看起来像下面的方法的东西 - 要么insertNewData或loadNewData，但仍然不知道那里发生了什么。你可能是对的！ – e2l3n 2011-12-19 11:24:24

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: [NSURL URLWithString:urlStr]]; 
NSData *dataReply = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

的问题是代码，您正在执行主线程同步网络请求。

这意味着UI将完全阻塞，直到请求完成。
你将不得不这样做异步。你会在StackOverflow上找到很多代码。

来源

2011-12-19 11:33:21 vikingosegundo

非常感谢！ – e2l3n 2011-12-19 11:39:37

加载视图显得太慢

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