I have some png files in my iPhone app project. They work fine when I build for the simulator. But when I build for the device, suddenly every single png file generates the dreaded "while reading such-and-such.png pngcrush caught libpng error: ... Could not find file: ..."
As I say, everything builds and runs great with the simulator. It's only when I change the scheme to build for the device that I get the errors.
I tried cleaning and rebuilding.
I tried manually deleting the Products directory.
I tried restarting my system.
I tried using the files in a different project (same results there).
The only thing I have found that works is to open the files and resave them. However, this is a less than optimal solution because I have hundreds of PNG files all suffering from this issue. I would rather understand what the issue is so that I can fix it directly.
Any ideas?
It sounds as though you've got PNG files that were recompressed with Apple's rogue "pngcrush" Xcode program, which writes files that are not valid PNGs. Look for the string "CgBI" near the beginning of the file (starting at the 12th byte) where "IHDR" should be. There are applications (including the Apple version of "pngcrush") that can undo the problem.
Worked around this issue by writing a quick-and-dirty recursive file re-saver. I've verified that simply running this against my project directory fixes the 459 errors I was seeing. Here's the pertinent code in case it helps anyone.
- (IBAction) btnGo_Pressed:(id) sender {
// The path to search is specified by the user
NSString *path = self.txtPathToSearch.stringValue;
// Recursively find all files within it
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *subpaths = [fileManager subpathsOfDirectoryAtPath:path error:nil];
// Look for pngs
int totalImagesResaved = 0;
for (int j=0; j<[subpaths count]; j++) {
NSString *fullPath = [path stringByAppendingPathComponent:[subpaths objectAtIndex:j]];
// See if this path ends with a ".png"
if ([fullPath compare:#".png" options:NSCaseInsensitiveSearch range:NSMakeRange([fullPath length] - 4, 4)] == NSOrderedSame) {
// Got one. Now resave it as a png
NSImage *image = [[NSImage alloc] initWithContentsOfFile:fullPath];
[self saveImage:image asPngWithPath:fullPath];
totalImagesResaved++;
}
}
// Status report
NSAlert *alert = [NSAlert alertWithMessageText:#"Done" defaultButton:#"OK" alternateButton:nil otherButton:nil informativeTextWithFormat:#"Encountened %li paths. Resaved %i .pngs.", (unsigned long)[subpaths count], totalImagesResaved];
[alert runModal];
}
- (void) saveImage:(NSImage *) image asPngWithPath:(NSString *) path
{
// Cache the reduced image
NSData *imageData = [image TIFFRepresentation];
NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData];
imageData = [imageRep representationUsingType:NSPNGFileType properties:nil];
[imageData writeToFile:path atomically:YES];
}
My app has some content dumping in document folder periodically. And i have used the below code to calculate my total app consumed memory size. But i see its different from what i see from settings\usage. My code shows very less memory. I am not able to track where i am going wrong in calculating/ or have i missed folder paths.
I have calculated my app size as follows:
NSString *folderPath = [[NSBundle mainBundle] bundlePath];
NSArray *filesArray = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:folderPath error:nil];
NSEnumerator *filesEnumerator = [filesArray objectEnumerator];
NSString *fileName;
unsigned long long int fileSize = 0;
while (fileName = [filesEnumerator nextObject]) {
NSDictionary *fileDictionary = [[NSFileManager defaultManager] attributesOfItemAtPath: [folderPath stringByAppendingPathComponent:fileName] error:nil];
fileSize += [fileDictionary fileSize];
};
The above code returns the actual file size. The value shows in the settings/usage shows the allocated size. The allocated size shall be more than the actual size.
That's why your calculated value and the setting/usage values are not matching.
If you need to access the allocated size of a file please use NSURLTotalFileAllocatedSizeKey in NSURL class. There is no methods/ property available in NSFileManager class to get the allocated size [As far as i know].
Please go through details of File Property Keys of the NSURL class.
FYI: We shall get permission error if you try to access the /Library/Caches/Snapshot folder in Home directory of sanboxed app.
This may be helpful to you.
My app is using the NSDocumentDirectory to save images in it, I just wanna ask if its the safe way to save images(100 maximum). I have read several thread & questions with answers about it, though I dont know which to follow.Some say that its okay to save there. Some say I shouldnt use NSDocumentDirectory for saving, because it will be back-up by the iCloud. So where can I save it that when the user exit the app then run the app again, then images should still be there?. I dont know much about the tmp directory or cache directory. But if its either one of the 2 that I should use, How can I use them in my code here:
NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask ,YES );
NSString *documentsDir = [paths objectAtIndex:0];
NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"Images%d.png", i]];
ALAssetRepresentation *rep = [[info objectAtIndex: i] defaultRepresentation];
UIImage *image = [UIImage imageWithCGImage:[rep fullResolutionImage]];
//----resize the images
image = [self imageByScalingAndCroppingForSize:image toSize:CGSizeMake(256,256*image.size.height/image.size.width)];
NSData *imageData = UIImagePNGRepresentation(image);
[imageData writeToFile:savedImagePath atomically:YES];
Thank you so much for the help.
The tmp and cache directories are periodically cleaned up by iOS. If the images are for general use, use the camera roll as the other two answers suggest. However if these images are intended just for the scope of your app, you can still safely store them in the Documents directory, you just have to include an "exclude from iCloud backup" function call to each file after saving, in order to prevent Apple rejecting your app for using too much iCloud space. Of course there's a trade-off, disabling this means the user will lose their photos anyway should they delete the app or get another device(etc), but this caveat is preferable to not getting the App on the store at all.
To disable iCloud backup on a file, there's two methods for iOS versions > 5.0:
UPDATE! MERGED BOTH METHODS INTO A SINGLE FUNCTION THAT AUTOMATICALLY HANDLES iOS VERSION:
#include <sys/xattr.h> // Needed import for setting file attributes
+(BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)fileURL {
// First ensure the file actually exists
if (![[NSFileManager defaultManager] fileExistsAtPath:[fileURL path]]) {
NSLog(#"File %# doesn't exist!",[fileURL path]);
return NO;
}
// Determine the iOS version to choose correct skipBackup method
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if ([currSysVer isEqualToString:#"5.0.1"]) {
const char* filePath = [[fileURL path] fileSystemRepresentation];
const char* attrName = "com.apple.MobileBackup";
u_int8_t attrValue = 1;
int result = setxattr(filePath, attrName, &attrValue, sizeof(attrValue), 0, 0);
NSLog(#"Excluded '%#' from backup",fileURL);
return result == 0;
}
else if (&NSURLIsExcludedFromBackupKey) {
NSError *error = nil;
BOOL result = [fileURL setResourceValue:[NSNumber numberWithBool:YES] forKey:NSURLIsExcludedFromBackupKey error:&error];
if (result == NO) {
NSLog(#"Error excluding '%#' from backup. Error: %#",fileURL, error);
return NO;
}
else { // Succeeded
NSLog(#"Excluded '%#' from backup",fileURL);
return YES;
}
} else {
// iOS version is below 5.0, no need to do anything
return YES;
}
}
If your app must support 5.0, then unfortunately your only option is to save those photos in the Caches directory, which means they won't be backed up (this not causing an App Store rejection for that reason), but whenever the storage watchdog decides it's time to clean the Caches folder, you'll lose those photos. Not an ideal implementation at all, but such is the nature of the beast in 5.0, where Apple added in Backup exclusion as an afterthought.
EDIT: Forgot to answer the 'how to save to the tmp/cache directory' part of the question. If you do decide to go down that path:
Saving to tmp:
NSString *tempDir = NSTemporaryDirectory();
NSString *savedImagePath = [tempDir stringByAppendingPathComponent:[NSString stringWithFormat:#"Images%d.png", i]];
(note that this won't appear to have any effect in the simulator, but it works as expected on device)
Saving to Cache:
NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask,YES)lastObject];
NSString *savedImagePath = [cacheDir stringByAppendingPathComponent:[NSString stringWithFormat:#"Images%d.png", i]];
If you want the user to be able to use the images in other apps or view them along with their photos, use the photo album as Mike D suggest. If the files are something you generate locally for use with your app only, then you should probably use the documents directory. You can expose the documents directory to iTunes with the info.plist option "Application supports iTunes file sharing" which will allow the user to add or delete files through iTunes, but the files will not be exposed to other apps
You are saving scaled images so they are really only useful for your game. They are not going to be very large and will not take up much space. You could save them in the Library directory for the app and avoid the whole iCloud thing, as it doesn't sound like there is any reason to back them up. Also, saving the the Library avoid the possibility of the user deleting them, if for some other reason you have iTunes sharing turned on.
Update: code for saving to the app Library directory
- (void)saveSequences:(NSMutableDictionary*)sequences
{
NSArray *path = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libDirectory = [path objectAtIndex:0];
NSString *settingsPath = [libDirectory stringByAppendingPathComponent:#"userSequences.plist"];
NSLog(#"settingsPath %#", settingsPath);
[sequences writeToFile:settingsPath atomically:YES];
}
// The code below gets the path to a named directory in the 'Documents' folder - and if it doesn't exist, creates it. Adjust it to use the Library path, if you decide to go that route.
- (NSString *)getDirectoryBySequenceName:(NSString *)sequenceName
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * documentDirectory = [paths objectAtIndex:0];
NSString * sequenceDirectory = [documentDirectory stringByAppendingPathComponent:sequenceName];
NSError *error;
BOOL success = [[NSFileManager defaultManager] createDirectoryAtPath:sequenceDirectory
withIntermediateDirectories:YES
attributes:nil error:&error];
if (!success) {
NSLog(#"Error creating data path: %#", [error localizedDescription]);
}
return sequenceDirectory;
}
Depending on the purpose of your app, you could save it to the photos app (UIImageWriteToSavedPhotosAlbum(image, self, nil, nil) I think, Apple reference). Saving here, or in the documents directory (or any sub folder), will allow the user backup those images to iCloud or iTunes, if the user chooses too and/or if they have set up iCloud.
Since you state the images need to persist between launches, the temp or cache directory get emptied when the application is removed from memory, maybe sooner (the O/S decides).
More about the iOS file system.
I use this method to get the free space on the disk, extracted from a code found after some researches.
float freeSpace = -1.0f;
NSError* error = nil;
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSDictionary* dictionary = [[NSFileManager defaultManager] attributesOfFileSystemForPath:[paths lastObject] error: &error];
if (dictionary) {
NSNumber* fileSystemSizeInBytes = [dictionary objectForKey:NSFileSystemFreeSize];
freeSpace = [fileSystemSizeInBytes floatValue];
}
I wonder why when runing this, it gives me a free space of 3660062720.000000 bytes
that would give 3,408699035644531 Gb (/1024/1024/1024)
But looking into my iPhone setting -> general info (and also into iTunes), I'm said that my iPhone has only 3.2 Gb left.
Where is the mistake ?
It appears that sometimes the free space is reported incorrectly https://discussions.apple.com/thread/2566412?threadID=2566412
EDIT: I tried the following code and noticed that on my device, there was also a ~200MB discrepancy. Maybe that storage is reserved for the system somehow?
NSDictionary *fsAttr = [[NSFileManager defaultManager] fileSystemAttributesAtPath:NSHomeDirectory()];
unsigned long long freeSpace = [[fsAttr objectForKey:NSFileSystemFreeSize] unsignedLongLongValue];
NSLog(#"%llu", freeSpace);
NSLog(#"%f", freeSpace / 1073741824.0);
in my iPhone app I'm using file manager to check size of file,code is working fine on simulator, but when I run the same app on iphone it is saying file size is zero even though file size is greater than zero, I am using following code:
NSArray *paths1 = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory1 = [paths1 objectAtIndex:0];
documentsDirectory1 = [documentsDirectory1 stringByAppendingPathComponent:#"XML"];
NSString * szDestPath1 = [documentsDirectory1 stringByAppendingPathComponent:#"Extras"];
NSString *URL2 = [szDestPath1 stringByAppendingPathComponent:#"config.xml"];
NSLog(#"%#",URL2);
NSError *attributesError = nil;
NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:URL2 error:&attributesError];
int _fileSize = [fileAttributes fileSize];
NSLog(#"_fileSize:%U",_fileSize); //0 if empty
How can I solve this, can anyone help me? thanx in advance.
Are you sure that the file exists?
Usually if a piece of code that involves files works fine on the simulator but not on the device it is because of wrong filenames. Most simulators run on a case-insensitive filesystem, but the device has a case-sensitive filesystem.
So please check again if you use the correct file path.
You could add something like this to make sure that the file exists:
if (![[NSFileManager defaultManager] fileExistsAtPath:URL2]) {
NSLog(#"File does not exist");
}