NSDocumentDirectory合法保存和加載設備上的圖像？

Question

下面的代碼工作在模擬器，但崩潰的設備，因爲IMG是零：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 

    for (NSString* path in userImages) { 
     NSLog(@"image at %@", path); //logs "image at userImage0.png" 
     NSString *getImagePath = [documentsDirectory stringByAppendingPathComponent:path]; 
     UIImage *img = [UIImage imageWithContentsOfFile:getImagePath]; 
     unichar ch = [path characterAtIndex:9]; 
     NSLog(@"Ch = %c", ch); //correctly logs "0" 
     if (ch == '0') { 
      [self.images insertObject:img atIndex:0]; //this throws the error 
     } 
    } 

爲什麼當設備上運行，但不是在模擬器上是IMG零？圖像最初是這樣保存的：

NSString *docsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES) objectAtIndex:0]; 
NSString *imageName = @"userimage0.png"; 
NSString *imagePath = [docsDir stringByAppendingPathComponent:imageName]; 
[UIImagePNGRepresentation(img) writeToFile:imagePath atomically:YES]; 

Answer 1

對不起，這是一個大寫問題。 userimage vs userImage。模擬器不關心（我希望它），但設備。