如何在iOS 9和iOS 10上清除缓存

Question

I want to clean cache on all kinds of version's iOS,however, it only work on iOS 7 and iOS 8 . On iOS 9 and iOS 10,the same code didn't work,this make me very confused.

In order to find the reason,I create a new demo with the same clean cache method and run on iOS 10,everything goes well,and cleaned cache successfully.So I think,the code I use to clean cache is no problem. But why it didn't work on my own project when run on iOS 9 and iOS 10?

For the sake of confirming whether the code has been calling when run on iOS 9 and iOS 10,I add a breakpoint in this method,it stopped at there.Method had been called,but didn't clean cache. The method code I use to clean cache is:

-(void)removeCache
{
    //===============清除缓存==============
    NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:cachePath];

    // NSLog(@"文件数 ：%lu",(unsigned long)[files count]);
    for (NSString *p in files)
    {
        NSError *error;
        NSString *path = [cachePath stringByAppendingPathComponent:p];
        if([[NSFileManager defaultManager] fileExistsAtPath:path])
        {
            [[NSFileManager defaultManager] removeItemAtPath:path error:&error];
        }
    }
}

I really need some help,this issue had confused me 3 day.

Answer 1

It seems that iOS 9 and iOS 10 store some files in the Caches folder that your app isn't allowed to delete.

You can use the NSFileManager isDeletableFileAtPath: method to check.

-(void)removeCache
{
    //===============清除缓存==============
    NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:cachePath];

    // NSLog(@"文件数 ：%lu",(unsigned long)[files count]);
    for (NSString *p in files)
    {
        NSError *error;
        NSString *path = [cachePath stringByAppendingPathComponent:p];
        if ([[NSFileManager defaultManager] fileExistsAtPath:path] && [[NSFileManager defaultManager] isDeletableFileAtPath:path])
        {
            if (![[NSFileManager defaultManager] removeItemAtPath:path error:&error]) {
                NSLog(@"Error trying to delete %@: %@", path, error);
            }
        } else {
            NSLog(@"Can't delete %@", path);
        }
    }
}