I've created NSManagedObject* imagesArrayData that stores strings (paths) to images stored in the documents directory:
- (void)setImagesArray:(NSMutableArray *)imagesArray {
NSMutableArray* newImagesArray = [NSMutableArray new];
int i = 1;
for (UIImage* image in imagesArray) {
//generate path to createdFile
NSString* fileName = [NSString stringWithFormat:#"%#_%d", self.name, i];
NSString* filePath = [self documentsPathForFileName:fileName];
//save image to disk
NSData *imageData = UIImagePNGRepresentation(image);
[imageData writeToFile:filePath atomically:YES];
//add image path to CoreData
[newImagesArray addObject:filePath];
i++;
}
//set new value of imagesArray
imagesArrayData = [NSKeyedArchiver archivedDataWithRootObject:newImagesArray];
I am now not showing pathsToImages in header file, but property imagesArray:
-(NSMutableArray*) imagesArray {
NSMutableArray* images = [NSMutableArray new];
NSArray* imagePaths = [NSKeyedUnarchiver unarchiveObjectWithData:imagesArrayData];
for (NSString* imagePath in imagePaths) {
UIImage *image = [[UIImage alloc] initWithContentsOfFile: imagePath];
[images addObject:image];
}
return images;
The problem is, that whenever I want to get to [imagesArray objectatIndex:xxx], the imagesArray getter is called, and it takes time to recreate the full array. When trying to switch fast between images, the UI slows down.
What would be the elegant way to overcome this problem? Maybe creating another array full of images and updating it from time to time? Maybe something else? Please, help.
One thing you could do is refactor your getter to lazily load the array. If it is already defined, simply return it. If not, build it:
-(NSMutableArray*) imagesArray
{
if (!_imagesArray)
{
NSMutableArray* _imagesArray = [NSMutableArray new];
NSArray* imagePaths =
[NSKeyedUnarchiver unarchiveObjectWithData: imagesArrayData];
for (NSString* imagePath in imagePaths)
{
UIImage *image = [[UIImage alloc] initWithContentsOfFile: imagePath];
[_imagesArray addObject:image];
}
return _imagesArray;
}
I'm not sure what you mean about updating an array of images from time to time.
If your array of image names changes you will need some method to respond to those changes.
Related
I have an app that creates an animation from images stored in a group in my project navigator (not Images.xcassets). This code "works" in that it animates properly, but using imageNamed causes a memory leak because the image files are not getting deallocated.
I can't figure out why adding with imageNamed: works adds images to my array, but imageWithContentsOfFile: doesn't.
A little info on the mechanics of my app:
self.myPhoto is set on the segue from another ViewController. The number of images can vary, so I test to see the file is "there" before adding it to the array.
Filenames follow this naming convention:
"1-1.jpg"
"2-1.jpg"
"2-2.jpg"
"99-1.jpg"
"99-2.jpg"
"99-3.jpg"
"99-4.jpg"
This code works, but the images don't deallocate, causing a memory leak:
- (void)startAnimation {
NSMutableArray *imageArray = [[NSMutableArray alloc] init];
for (int imageNumber = 1; self.myPhoto != nil; imageNumber++) {
NSString *fileName = [NSString stringWithFormat:#"%#-%d.jpg", self.myPhoto, imageNumber];
// check if a file exists
if ([UIImage imageNamed:fileName]) {
// if it exists, add it to the array
[imageArray addObject:[UIImage imageNamed:fileName]];
} else {
// otherwise, don't add image to the array
break;
}
}
self.myImageView.animationImages = imageArray;
self.myImageView.animationDuration = 1.5f;
self.myImageView.animationRepeatCount = 0;
self.myImageView.contentMode = UIViewContentModeScaleAspectFit;
[self.myImageView startAnimating];
}
I ran Instruments on it and saw I had a memory leak emanating from my animation. Digging around a little on StackOverflow, I discovered the manner I'm adding my files to myArray results in images not getting deallocated.
So I tried this, instead:
- (void)startAnimation {
NSMutableArray *imageArray = [[NSMutableArray alloc] init];
for (int imageNumber = 1; self.myPhoto != nil; imageNumber++) {
NSString *fileName = [NSString stringWithFormat:#"%#-%d", self.myPhoto, imageNumber];
// check if a file exists
if ([UIImage imageNamed:fileName]) {
// if it exists, add it to the array
[imageArray addObject:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle]pathForResource:[NSString stringWithFormat:#"%#", fileName] ofType:#"jpg"]]];
NSLog(#"%# added to imageArray", fileName);
} else {
// otherwise, don't add image to the array
break;
}
}
NSLog(#"There are %lu images in imageArray", (unsigned long)imageArray.count);
self.myImageView.animationImages = imageArray;
self.myImageView.animationDuration = 1.5f;
self.myImageView.animationRepeatCount = 0;
self.myImageView.contentMode = UIViewContentModeScaleAspectFit;
[self.myImageView startAnimating];
}
When I do it this way, the page where the animation loads appears, but the images don't get added to my array--the . This is a well-documented issue. Here are a few posts covering this problem:
Dirty Memory because of CoreAnimation and CG image
How do I use imageWithContentsOfFile for an array of images used in an animation?
Thank you for reading. I'm stumped, though I'm confident the resolution to this problem is a startlingly stupid oversight on my part. Prove me right ;)
I made some minor changes out of desperation and I stumbled into the "answer". Comments note where I made changes:
- (void)startAnimation {
NSMutableArray *imageArray = [[NSMutableArray alloc] init];
for (int imageNumber = 1; self.myPhoto != nil; imageNumber++) {
// I set the filename here, adding .jpg to it
NSString *fileName = [NSString stringWithFormat:#"%#-%d.jpg", self.myPhoto, imageNumber];
// check if a file exists
if ([UIImage imageNamed:fileName]) {
// if it exists, add it to the array
// I blanked out ofType, as it's set when I create the local fileName variable
[imageArray addObject:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle]pathForResource:[NSString stringWithFormat:#"%#", fileName] ofType:#""]]];
} else {
// otherwise, don't add image to the array
break;
}
}
self.myImageView.animationImages = imageArray;
self.myImageView.animationDuration = 1.5f;
self.myImageView.animationRepeatCount = 0;
self.myImageView.contentMode = UIViewContentModeScaleAspectFit;
[self.myImageView startAnimating];
}
I'm using MHVideoPhotoGallery to create gallery's of images that are stored on my website. The current way to add images (as shown in the example on Github) is
MHGalleryItem *photo1 = [MHGalleryItem.alloc initWithURL:#"*ENTER IMAGE URL HERE*"
galleryType:MHGalleryTypeImage];
MHGalleryItem *photo2 = [MHGalleryItem.alloc initWithURL:#"*ENTER IMAGE URL HERE*"
galleryType:MHGalleryTypeImage];
MHGalleryItem *photo3 = [MHGalleryItem.alloc initWithURL:#"*ENTER IMAGE URL HERE*"
galleryType:MHGalleryTypeImage];
self.galleryDataSource = #[#[photo1,photo2,photo3]];
But I want to add hundreds of images and this is not the most ideal way to do it. What would be an easier way for me to accomplish this?
Thanks!
You have to start with a list of the URLs. What I would do is put this in a text file in my bundle. In code, when the app runs, I would open the text file (as an NSString) and split it into an NSArray. Now I've got an NSArray of the URLs. I would then cycle through the NSArray. So now we're inside a loop. For each item the array, I would initialize the MHGalleryItem and then add it to a previously created NSMutableArray with addObject:. Thus we have a two or three-line loop which is repeated, running through all the URLs.
The following is pseudo-code and untested (so it might contain errors), but it should give the general idea of the structure I'm suggesting:
NSMutableArray* temp = [NSMutableArray new];
NSString* s =
[NSString stringWithContentsOfFile:
[[NSBundle mainBundle] pathForResource:#"urls" ofType:#"txt"]
encoding:NSUTF8StringEncoding error:nil];
NSArray* urls = [s componentsSeparatedByString:#"\n"];
for (NSString* url in urls) {
MHGalleryItem *item = [[MHGalleryItem alloc] initWithURL:url
galleryType:MHGalleryTypeImage];
[temp addObject:item];
}
self.galleryDataSource = temp;
Loop. If you're putting numbers at the end of your variable names, you need a loop and/or an array.
NSMutableArray * photos = [NSMutableArray new];
NSArray * photoPaths = [NSArray arrayWithContentsOfFile:plistContainingPhotoPaths];
for( NSString * path in photoPaths ){
NSURL * photoURL = [NSURL URLWithString:path];
MHGalleryItem * photo = [[MHGalleryItem alloc] initWithURL:photoURL
galleryType:MHGalleryTypeImage];
[photos addObject:photo];
}
And don't use dot syntax for alloc, or your code will burst into flames.
Use a naming protocol on your website such as:
www.mywebsite.com/appImageGallery/insertImageNumber
And replace the insertImageNumber with the number of you image. Then add this for loop to get all of the images and add them to the array.
NSMutableArray *mutableGalleryDataSource = [self.galleryDataSource mutableCopy]
for(int i = 0; i < numberOfImagesOnWebsite; i++){ //replace numberOfImagesOnWebsite with the number of images on your website.
MHGalleryItem *newItem = [MHGalleryItem.alloc initWithURL:[#"www.mywebsite.com/appImageGallery/" stringByAppendingString:[NSString stringWithFormat: #"%i", i]] galleryType:MHGalleryTypeImage];
[mutableGalleryDataSource addObject:newItem];
}
self.galleryDataSource = mutableGalleryDataSource;
There is also an -addObjectsFromArray method on NSMutableArray.
I've a tableview which has list of images and image thumbnail (image list and thumbnails are parsed from JSON object), I'm adding image data objects to imagesArray like this -
ImageData *imageDataObject = [[ImageData alloc]initWithImageId:[[imageListArray
objectAtIndex:indexPath.row] imageId] imageData:imageData];
[imagesArray addObject:imageDataObject];
ImageData object
#property (nonatomic, strong) NSString* imageId;
#property (nonatomic, strong) NSData* imageData;
allImagesArray like this
[ImageData object1,ImageData object2,....]
I want to assign imageData of the object from this array based on selectedImageId to
UIImage* image =[[UIImage alloc] initWithData:........];
I'm not able to think of a way to get to that imageData based on selectedImageId
Please help.
Update -
Thank you all for the help, I could do it.
One of the possible way will be, iterate through the array, find your selectedImageId from the dictionary and use it.
Example:
ImageData *imageDataObject = nil;
for(int i=0; i<allImagesArray.count;i++){
NSDictionary *dict= allImagesArray[i];
imageDataObject = [dict objectForKey:selectedImageId];
if(imageDataObject != nil){
UIImage* image =[[UIImage alloc] initWithData:........];
//do whatever
break;
}
}
As per your EDIT:
What you have is an array of ImageData objects [ImageData1,ImageData2,...]. For each ImageData object, you have imageId and imageData property and what you want is simply compare the selectedImageId with this imageId and get the imageData from that.
So for that, in your PPImageViewController, you can iterate the allImagesArray like this and get the imageData.
for(ImageData* imgDataObj in self.allImagesArray){
if([imgDataObj.imageId isEqualToString:self.selectedImageId]){
UIImage* image =[[UIImage alloc] initWithData:imgDataObj.imageData];
}
}
So you have:
NSArray* allImagesArray = #[#{#"some_image_id_in_NSString_1":#"the data in NSData 1"}, #{#"some_image_id_in_NSString_2":#"the data in NSData 2"}];
As a property of PPImageViewController.
Assuming the imageid is an NSString and imagedata is NSData, you can create a method something like this on PPImageViewController:
- (UIImage*) findSelectedImage
{
UIImage* selectedImage;
for(NSDictionary* d in allImagesArray)
{
NSString* currentKey = [[d allKeys] objectAtIndex:0];
if([currentKey isEqualToString:[self selectedImageId]])
{
NSData* imageData = [d objectForKey:currentKey];
selectedImage = [UIImage imageWithData:imageData];
break;
}
}
return selectedImage;
}
Then call it like this, maybe on your viewDidLoad method:
UIImage* selectedImage = [self findSelectedImage];
Hope it help.
I see you are adding ImageData objects directly into the Array. You could have just used a NSDictionary instead. The key can be imageID (assuming it to be unique) and value will be the imageData object. Then pass the dictionary instead of array to PPImageViewController.
NSMutableDictionary *imageData = [NSMutableDictionary dictionary];
ImageData *imageDataObject = [[ImageData alloc]initWithImageId:[[imageListArray
objectAtIndex:indexPath.row] imageId] imageData:imageData];
[imageData setObject:imageDataObject forKey:imageId];
And then within PPImageViewController, you can easily get the imageDataObject based on selected imageID like this:
ImageData *imageDataObject = allImagesDictionary[selectedImageID];
EDIT:
NSArray *imageIndexes = [allImagesDictionary allKeys];
// Now use imageIndexes to populate your table. This will guarantee the order
// Fetch the imageId
selectedImageID = imageIndexes[indexPath.row];
// Fetch the imageData
ImageData *imageDataObject = allImagesDictionary[selectedImageID];
I am trying to add Images fetched from an external service to an NSMutableDictionary and seeing weird results. This is what I am doing:
- (void)fetchImages{
//Fetch Item Brand Images
//self.itemBrands is an NSArray of NSDictionaries
for (NSDictionary *itemBrand in self.itemBrands){
NSString *currentItemId = [itemBrand objectForKey:#"ITEM_ID"];
//Valid Item Id. This Log message is displayed
NSLog(#"Current Item Id: %#",currentItemId);
NSString *currentItemImageUrl = [[IMAGE_URL stringByAppendingString:currentItemId] stringByAppendingString:#".png"];
//Image URL is valid. This log message is displayed
NSLog(#"Current Image URL: %#",currentItemImageUrl);
NSURL *url = [NSURL URLWithString:currentItemImageUrl];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if (image == nil){
//This log message is displayed when image is not present
NSLog(#"Image not Present 1");
}else{
//This log message is displayed when image is present
NSLog(#"Image Present 1");
[self.itemBrandImages setObject:image forKey:currentItemId];
}
}
//This for loop is not being executed at all. No log messages displayed.
for(id key in self.itemBrandImages){
NSLog(#"Current Item Id2: %#",key);
if ([self.itemBrandImages objectForKey:key] == nil){
NSLog(#"Image Not Present 2");
}else{
NSLog(#"Image Present 2");
}
}
}
The 2nd for loop where I am iterating over self.itemBrandImages is not being executed at all. None of the log messages inside are being displayed.
I tried the following before posting my issue here:
1) Researched similar problems in stack overflow and incorporated suggestion from one of them. The suggestion was "Perform an alloc init of the NSMUtableDictionary" in the init method of the .m file. This didn't help either.
2) To isolate the issue, I even tried adding a simple string to the NSMUtableDictionary instead of the image but even that does not seem to retained.
I am really confused as as to what I am missing or doing wrong here. Inputs are really appreciated.
Thanks,
Mike G
Perhaps:
for(NSString *key in [self.itemBrandImages allKeys])
I did an alloc init of the NSMutableDictianary right in my fetchImages method and it worked! Not sure why the alloc init in the init method did not work.
So here are my takeaways from this issue:
1) If you have an Array or dictionary #property that you are just getting and setting and not really adding or deleting objects to, then you don't need to explicitly alloc init them.
2) If you have an Array or dictionary #property that you are adding or deleting objects to ,you need to explicitly alloc init them.
Are my above statements true? Would love to hear your inputs on this.
Thanks,
Mike
New code:
- (void)fetchImages{
//Fetch Item Brand Images
self.itemBrandImages = [[NSMutableDictionary alloc] init];
for (NSDictionary *itemBrand in self.itemBrands){
NSString *currentItemId = [itemBrand objectForKey:#"ITEM_ID"];
NSLog(#"Current Item Id in ItemList: %#",currentItemId);
NSString *currentItemImageUrl = [[#"http://anythingtogo.freeiz.com/images/"stringByAppendingString:currentItemId] stringByAppendingString:#".png"];
NSLog(#"Current Image URL in ItemList: %#",currentItemImageUrl);
NSURL *url = [NSURL URLWithString:currentItemImageUrl];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if (image == nil){
NSLog(#"Image not Present 1");
}else{
NSLog(#"Image Present 1");
[self.itemBrandImages setObject:#"Test" forKey:currentItemId];
}
}
I'm displaying a set of images in my app. I've got the code working when I load the image from the Resources folder, like so:
- (void)viewDidLoad
{
NSMutableArray *array = [[NSMutableArray alloc] init];
[array addObject:[NSString stringWithFormat: #"pic_a"]];
[array addObject:[NSString stringWithFormat: #"pic_b"]];
[array addObject:[NSString stringWithFormat: #"pic_c"]];
[array addObject:[NSString stringWithFormat: #"pic_d"]];
int index = arc4random() % [array count];
NSString *pictureName = [array objectAtIndex:index];
NSString* imagePath = [ [ NSBundle mainBundle] pathForResource:pictureName ofType:#"png"];
UIImage *img = [ UIImage imageWithContentsOfFile: imagePath];
if (img != nil) { // Image was loaded successfully.
[imageView setImage:img];
[imageView setUserInteractionEnabled:NO];
[img release]; // Release the image now that we have a UIImageView that contains it.
}
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
However, if I create an "images" group within the "Resources" group, and put try to load the images from there, the image within the view shows up blank.
[array addObject:[NSString stringWithFormat: #"images/pic_a"]];
[array addObject:[NSString stringWithFormat: #"images/pic_b"]];
[array addObject:[NSString stringWithFormat: #"images/pic_c"]];
[array addObject:[NSString stringWithFormat: #"images/pic_d"]];
I'd like to separate the images out from the nib files and all the other cruft. What's the best way to do that?
Even if you have the images in a separate group within Resources, you can load them by calling the name, e.g. use this one line
UIImage *img = [UIImage imageNamed:[array objectAtIndex:index]];
in place of these three lines:
NSString *pictureName = [array objectAtIndex:index];
NSString* imagePath = [ [ NSBundle mainBundle] pathForResource:pictureName ofType:#"png"];
UIImage *img = [ UIImage imageWithContentsOfFile: imagePath];
You will still fill the array simply by
[array addObject:[NSString stringWithFormat: #"pic_a"]];
If you have both jpg and png files, then you should append .png to the end of the file names. Otherwise, leaving it off is fine.
Try using the imageNamed: method instead of imageWithContentsOfFile:
You need to create a physical folder called images (it should have a blue color instead of the usual yellow color)
Remember that adding groups inside your project it is simply for organization and look within Xcode. You adding a group will not change the fact that the images will be saved in the main bundle. If you are trying to find them using the images group in the string it will not find them.
There are some things you can do to make this work, but in reality you don't need to.