nscache

问题 I am working with NSCache , I am using NSCache to store images. I am showing images on UITableView . Whenever I add images first they are resized and then added to the table and then to NSCache . eveything works fine. But whenever app goes to background when I close the app and open again, My Cache will be empty and again my app resizes images and then show it, because of which at first I see a empty table. I am not understanding why this is happening. Is this the intended behaviour of

问题 We are using NSCache for UIImages in our app. This works fine on iOS versions smaller than 7. When a memory warning occurs, NSCache releases objects as intended. However, on iOS 7, our app crashes shortly after the first memory warning. So it seems as if objects stored with NSCache are never released but the cache is growing until the app is crashing. Profiling with instruments confirms this suspicion. Did somebody else experience this problem and did you find a workaround or already track a

问题 I'm woking on a project in swift 3.0 where I cache the response from the server by using NSCache as to populate them in a UITableView. However for some reason I'm only seeing few images loading when the app loads for the first time, but if If i scroll and come back I see everything (end of retrieving the response from the server I reload my tableview too, but seems that not the case). I'm not sure what I''m exactly missing here, the code as bellow as to show how I cache the images. let

问题 I'm looking into a fairly simple mechanism for caching and and currently using NSCache (for the reason of memory management). Question is - does the cache persist between launches? It seems like no to me. I get objects put in cache just fine and can take them out of the cache while the app is running no problem. But once I relaunch, seems like the cache is gone. So is there a way to make the cache persist between launches? If so, how would you re-sync the cache from previous session to the

问题 I need to make a dictionary like NSCache which is thread-safe for keeping a cahce. However, once in a while, I would need to refresh the contents of the Cache. NSCache does not provide a method to iterate over its keys. What would be the alternative here ? NSMutableDictionary with synchronization ? 回答1: NSCache doesn't have such API. So, you should implement your own cache using NSMutaleDictionary or NSMapTable. The main idea is to track order of added objects and remove the older if

问题 I am using NSCache to store images. But problem here is once I switch between controllers , NSCache empties. I want the items to be there atleast until application is closed or user logs out . Lets say I have a tab view and I am storing images from the data in 1st tab . When I go to second tab and switch back to first ,NSCache is initialized again. Here is my code :- - (void)viewDidLoad { [super viewDidLoad]; if(imageCache==nil) { imageCache=[[NSCache alloc]init]; NSLog(@"initialising"); }

问题 I am using NSCache to store images. But problem here is once I switch between controllers , NSCache empties. I want the items to be there atleast until application is closed or user logs out . Lets say I have a tab view and I am storing images from the data in 1st tab . When I go to second tab and switch back to first ,NSCache is initialized again. Here is my code :- - (void)viewDidLoad { [super viewDidLoad]; if(imageCache==nil) { imageCache=[[NSCache alloc]init]; NSLog(@"initialising"); }

问题 Note: Please no libraries. This is important for me to learn. Also, there are a variety of answers on this but none that I found solves the issue nicely. Please don't mark as duplicate. Thanks in advance! The problem I have is that if you scroll really fast in the table, you will see old images and flickering. The solution from the questions I read is to cancel the URLSession data request. But I do not know how to do that at the correct place and time. There might be other solutions but not

问题 I would like to save images into the cache in TableViewcontroller. I wrote the following code, but cacheImage is always nil. @property (nonatomic,strong)NSCache *imageCache; @synthesize imageCache; - (void)viewDidLoad { [super viewDidLoad]; self.imageCache = [[NSCache alloc] init]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView

问题 I am downloading some mp3 files through my application using NSURLConnection. Actually where can I save the downloaded file. Someone says that saving in to NSDocumentDirectory will lead to app rejection. Can I save the file to NSCacheDictionary and retrieve this from itunes? I used this bit of code to save files to NSCacheDictionary NSString *cachesPath = [NSSearchPathForDirectoriesInDomains( NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex: 0]; NSString *documentsDirectoryPath =