I am trying to put a number tables in uiscrollview such that it can swipe through each (paging). This is done on nicely on TweetDeck.
I'm using https://github.com/andreyvit/SoloComponents-iOS/tree/master/ATPagingView
However im struggling to figure out how to do it without leaking memory.
- (UIView *)viewForPageInPagingView:(ATPagingView *)pagingView atIndex:(NSInteger)index {
myTableViewController *t = [[servicesController alloc] init];
t.delegate = self.navigationController; //such that the tableview can call nav controller
t.info = [array objectAtIndex:index]; //Data that is different for every page
return [t.view autorelease];
}
Does anyone have any suggestions as to how I should modify ATPagingView to accomodate for UIViewControllers instead of UIViews? Or any other examples?
Related
In my app the user can take a photo of their pet, or whatever, and that will show in the collection view as a circular picture. Using cellForItemAtIndexPath to check for the existence of a user generated photo (which is stored in the Documents directory as a png file), if not display a default photo.
Issues:
- When Scrolling the UICollectionView the image load halts the
smoothness of the scroll UI as the picture is going to appear on
screen.
- If you scroll the picture off the screen many times the
app crashes due to memory pressure.
QUESTION: Is there an efficient way of loading and keeping the images in memory without having to keep loading the image after the first time it is displayed?
I thought rasterizing the images would help, but it seems the UI scrolling and memory issues persist.
Here is the code:
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifierPortrait = #"allPetCellsPortrait";
AllPetsCell *cell = (AllPetsCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifierPortrait forIndexPath:indexPath];
CGRect rect = CGRectMake(cell.petView.center.x, cell.petView.center.y, cell.petView.frame.size.width, cell.petView.frame.size.height);
UIImageView *iv = [[UIImageView alloc] initWithFrame:rect];
//set real image here
NSString *petNameImage = [NSString stringWithFormat:#"%#.png", self.petNames[indexPath.section][indexPath.item]];
NSString *filePath = [_ad documentsPathForFileName:petNameImage];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath];
iv.image = nil;
if (fileExists){
[_allPetsCollectionView performBatchUpdates:^{
if (iv && fileExists) {
iv.image = [UIImage imageWithContentsOfFile:filePath];
}
} completion:^(BOOL finished) {
//after
}];
//loadedImage = YES;
[collectionView layoutIfNeeded];
}//file exists
else{
iv.image = [UIImage imageNamed:[NSString stringWithFormat:#"%#", self.contents[indexPath.section][indexPath.item]]];
[cell.petNameLabel setTextColor:[UIColor darkGrayColor]];//be aware of color over pictures
shadow.shadowColor = [UIColor whiteColor];
}
cell.petView.clipsToBounds = YES;
UIColor *color = MediumPastelGreenColor;
if ([[NSString stringWithFormat:#"%#", self.contents[indexPath.section][indexPath.item]] isEqualToString:#"addpet.png"]) {
color = MediumLightSkyBlueColor;
}
[cell.petView setBounds:rect forBorderColor:color];
[cell.petView addSubview:iv];
if (![[NSString stringWithFormat:#"%#", self.contents[indexPath.section][indexPath.item]] isEqualToString:#"addpet.png"])
[iv addSubview:cell.petNameLabel];
//TODO: optimize the cell by rasterizing it?
if ([_contents count] > 4) {
cell.layer.shouldRasterize = YES;
}
return cell;
}
Here is a screen shot:
Thanks!
Assigning an image to the collection view cell's imageView doesn't cost you any performance issues at all..
There are 2 problems here.
You are fetching the contents (datasource for the collection view) from within the collection view's delegate method. This is causing the delay.
You are adding the imageView holding the image again and again. Thus, each time the cell is displayed, a new imageView holding a newly fetched data is being added as the subView to the reused cell (As the new imageView covers the old one as both have the same frame, you wouldn't notice. And at the sametime this eats up memory). This is causing the memory pressure crash.
SOLUTION
FOR IMPROVING PERFORMANCE
Fetch the image contents from your model class(if you are using one), or from you viewController's viewDidLoad() (You should never fetch datasource from within the collection view's delegate method). Perform the fetching process in the background queue as it wouldn't affect your UI in any manner.
Store the contents onto an array and fetch the contents only from the array to populate your collection view cells.
FOR AVOIDING MEMORY CRASH
As long as you are not using a custom collection view cell, its better to remove all the subviews from the collectionViewCell's content view each time the cell is dequeued.
I hope this solves your problem :)
I recently discovered NSCache which is a dictionary type object that I can store my *already loaded image*s into and check to see if they are loaded with the -cellForItemAtIndexPath method.
I changed the above code to accommodate for this also by using a custom dispatch queue that would be sent to the main queue. This still causes a slight pause bump in the scrolling when the initial image is loaded but after that it is read from the image cache. Not totally optimal yet but I think I am headed in the right direction.
here is the code:
if (fileExists){
//DONE: implement NSCACHE and dispatch queue
const char *petImageQ = "pet image";
dispatch_queue_t petImageQueue = dispatch_queue_create( petImageQ, NULL);
//check to see if image exsists in cache - if not add it.
if ([_petImagesCache objectForKey:petNameImage] == nil) {
dispatch_async(petImageQueue, ^{
dispatch_async(dispatch_get_main_queue(), ^{
[collectionView performBatchUpdates:^{
iv.image = [UIImage imageWithContentsOfFile:filePath];
} completion:^(BOOL finished) {
//add to cache
[_petImagesCache setObject:iv.image forKey:petNameImage];
}];
});
});
}
else{
//load from cache
iv.image = [_petImagesCache objectForKey:petNameImage];
}
I hope this helps. Please add more to this for improving it!
I'm trying to implement a custom UICollectionView that shows all elements from the asset library. While displaying the items is not that big of a deal, I run into a weird bug which I think has to do something with the layout I'm using.
Let's start with some screenshots to indicate what's going on. I'll just post the links to these images to be easy on your scroll wheels :-)
1. Initial
https://dl.dropboxusercontent.com/u/607872/stackoverflow/01-uicollectionview-start.png
Everything ok.
2. Scrolled down
https://dl.dropboxusercontent.com/u/607872/stackoverflow/02-uicollectionview-scrolleddown.png
The images from the first row (which isn't visible anymore) repeat behind the images in the last row. The first one is invisible because it is entirely overlapped.
3. Scrolled up again
https://dl.dropboxusercontent.com/u/607872/stackoverflow/03-uicollectionview-scrollup.png
The first image (in the background) is from the same row, but should be the third. The 2nd and 3rd image are from the last row.
Here's some code. I hope I didn't miss any relevant stuff - if so, please let me know.
MultiImagePickerController.m (:UICollectionViewController, protocols: UICollectionViewDataSource, UICollectionViewDelegateFlowLayout)
- (void)loadView {
[...] // layout stuff
UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
[layout setScrollDirection:UICollectionViewScrollDirectionVertical];
_collectionView = [[UICollectionView alloc] initWithFrame:collectionRect collectionViewLayout:layout];
[_collectionView setDataSource:self];
[_collectionView setDelegate:self];
[_collectionView registerClass:[MultiImagePickerCell class] forCellWithReuseIdentifier:#"MultiImagePickerCellIdentifier"];
[_collectionView setBackgroundColor:[UIColor whiteColor]];
[self.view addSubview:_collectionView];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
MultiImagePickerCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"MultiImagePickerCellIdentifier" forIndexPath:indexPath];
if ( !cell ) {
CGSize sizeCell = [MultiImagePickerCell defaultSize];
cell = [[MultiImagePickerCell alloc] initWithFrame:CGRectMake( 0, 0, sizeCell.width, sizeCell.height )];
}
NSString *groupname = [self getKeyFromMutableDictionary:assetList forIndex:indexPath.section];
[cell addImageUsingAsset:[[assetList objectForKey:groupname] objectAtIndex:indexPath.row]];
return cell;
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
CGSize sizeCell = [MultiImagePickerCell defaultSize];
return CGSizeMake( sizeCell.width + 10.0, sizeCell.height + 10.0 );
}
MultiImagePickerCell - (void)addImageUsingAsset:(ALAsset *)asset;
This method adds a UIImageView and a UIImage to the cell to show the asset. Nothing special, in my opinion. When I set breakpoints in cellForItemAtIndexPath, I can see that the correct asset is being read from the assetList and the views are calculated correctly. The drawRect method of the cell is NOT implemented.
I think I experienced the same problem a few years back when I tried to programmatically create a UITableViewController, but I can't remember how I solved it.
Any suggestions?
Got it - I had to remove the subviews from my cells.
I am new to OS X and have started dealing with NSCollectionView. What I am trying to do is to take show NSCollectionView with array of imageView an labels. And on the selection of the image I want to open a new viewController class. I am able to show array of images and labels in collection view but I am completely lost on how to go to new view with the selection made in NSCollectionView and how to show the image selected to the new viewController class.
I am having an NSTabView and in that I am having customView in which I am showing CollectionView. And in awakeFromNib I am doing this to populate my collectionView
-(void)awakeFromNib
{
arrItems = [[NSMutableArray alloc]init];
NSMutableArray *imageArray=[[NSMutableArray alloc]initWithObjects:#"Baby-Girl-Wallpaper-2012-7.jpg",#"Cute-Little-Baby-Girl.jpg",#"Joker_HD_Wallpaper_by_RiddleMeThisJoker.jpg",#"The-Dark-Angel-Wallpaper-HD.jpg",#"hd-wallpapers-1080p_hdwallpapersarena_dot_com.jpg",#"lion_hd_wallpaper.jpg",#"Ganesh_painting.jpg",#"krishna-wallpaper.jpg",#"LeoN_userpic_79630_fire_lion_by_alex_barrera.jpg",#"273483.png",#"japan_digital_nature-wide.jpg", nil];
NSMutableArray *imageName = [[NSMutableArray alloc]initWithObjects:#"Baby-Girl",#"Cute-Little",#"Joker",#"The-Dark",#"hd-wallpapers", #"lion", #"Ganesh", #"krishna", #"LeoN_userpic",#"273483.png",#"japan_digital", nil];
for(int i = 0; i<[imageArray count]; i++)
{
STImageCollectionModal * img1 = [[STImageCollectionModal alloc] init];
img1.image = [NSImage imageNamed:[imageArray objectAtIndex:i]];
img1.imageName = [NSString stringWithFormat:#"%#",[imageName objectAtIndex:i]];
[arrItems addObject:img1];
}
[collectionView setContent:arrItems];
}
Later I created a new class named "STCollectionView" subclass of NSCollectionView and assigned the collectionView class to "STCollectionView" and with the help of setSelectionIndexes method I tried getting the index of the selected item by this
- (void)setSelectionIndexes:(NSIndexSet *)indexes
NSLog(#"%ld",[indexes firstIndex]);
But this method is getting called twice and whenever i put "super setSelectionIndexes" it gives me garbage value.
I am searching it all over but unable to find any kind of solution. Please help..
Thank you in advance.
Your question is confusing me.What i am thinking you can do this task simply by adding UICollectionView and in UICollectionView add custom UICollectionViewCell.In custom UICollectionViewCell add UIImageView and UILabel.
in the method
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *identifier = #"ReuseID";
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
cell.imageView.image = [UIImage imagewithNmaed:#"your Image name"];
cell.label.text = #"image Named";
return cell;
}
and in storyBoard hold CLT+drag to your UIViewController.In the method prepareForSgue Method pass data to your Next viewController.
I am developing my first MAC application, i downloaded one Example of PxListView
and i have to added one button and background image on cell xib and bind them with controller
and, when on button click i was set height of that cell is much bigger then other. that is done,
and work fine.
but now i want to develop like after is witch cell has open in that cell i want to add some extra contain (Controller) on it, so how it will possible using given example?
pls help me to give some suggest how it will be done.
for Ex like before click on button
after chick on button i want to develop like
You write
i have to added one button and background image on cell xib and bind them with controller
It sounds like you've subclassed PXListViewCell--for convenience, let's call your subclass TemplateListViewCell--and added a xib from which instances of TemplateListViewCell will be loaded in
+[PXListViewCell cellLoadedFromNibNamed:bundle:reusableIdentifier:]
In addition, there is a[t least one] button in TemplateListViewCell.xib.
You write
when on button click i was set height of that cell is much bigger then other. that is done, and work fine
It sounds like this button has as its action a method on TemplateListViewCell such as
- (IBAction)toggleDetail:(id)sender
{
//Code to grow or shrink the height of [self frame].
//...
}
In my approach to implementing -toggleDetail, two modifications to the PXListView files were necessary:
1. Adding a protocol method
- (void)listView:(PXListView *)aListView setHeight:(CGFloat)height ofRow:(NSUInteger)row;
to the PXListViewDelegate protocol.
2. Adding a property
#property (nonatomic, assign) BOOL expanded;
to PXListViewCell.
My implementation of -toggleDetail looks something like this:
- (IBAction)toggleDetail:(id)sender
{
BOOL wasExpanded = [self expanded];
NSRect oldFrame = [self frame];
CGFloat oldHeight = oldFrame.size.height;
CGFloat newHeight = oldHeight;
CGFloat heightIncrement = 0.0f;
if (wasExpanded) {
heightIncrement = -80.0f; //use whatever value is appropriate
} else {
heightIncrement = 80.0f; //use whatever value is appropriate
}
newHeight += heightIncrement;
[[[self listView] delegate] listView:[self listView] setHeight:newHeight ofRow:[self row]];
[[self listView] reloadData];
BOOL isExpanded = !wasExpanded;
[self setExpanded:isExpanded];
}
It might seem better to use [[self listView] reloadRowAtIndex:[self row]]; in place of [[self listView] reloadData], but unfortunately, this doesn't work: if the user hides the detail--shrinks the cell vertically--new cells which should appear on the screen do not.
You write
that is done, and work fine.
It sounds like you were able to implement successfully a method analogous to -[TemplateListViewCell toggleDetail:].
You write
but now i want to develop like after is witch cell has open in that cell i want to add some extra contain (Controller) on it, so how it will possible using given example? pls help me to give some suggest how it will be done.
It sounds like you want instances of TemplateListViewCell to contain extra views if they are expanded.
It might seem tempting to put this code into -[TemplateListViewCell toggleDetail], but this will not work out as we might hope. The trouble is, we need to handle cases where expanded cells have been scrolled out of view and scrolled back into view.
To get this right, we need to have a notion of expanded which persists beyond the usage of a PXListViewCell subclass instance: we either need to keep track of expansion in the PXListView itself or in its delegate.
The better--but less expedient--design seems to be to keep track of this information in the PXListView itself. For the sake of this question, however, I'll demonstrate how to keep track of cell expansion in the delegate. To do this, I'm expanding the PXListViewDelegate protocol and making other changes to the PXListView files:
1. Adding the methods
- (void)listView:(PXListView *)aListView setExpanded:(BOOL)expanded atRow:(NSUInteger)row;
- (BOOL)listView:(PXListView *)aListView expandedAtRow:(NSUInteger)row;
to PXListViewDelegate.
2. Adding the method
- (void)setCell:(PXListViewCell *)cell expandedAtRow:(NSUInteger)row
{
if ([[self delegate] respondsToSelector:#selector(listView:expandedAtRow:)]) {
[cell setExpanded:[[self delegate] listView:self expandedAtRow:row]];
}
}
to PXListView.
3. Calling -[PXListView setCell:expandedAtRow:] from -[PXListView layoutCells]
- (void)layoutCells
{
//Set the frames of the cells
for(id cell in _visibleCells)
{
NSInteger row = [cell row];
[cell setFrame:[self rectOfRow:row]];
[self setCell:cell expandedAtRow:row];
[cell layoutSubviews];
}
NSRect bounds = [self bounds];
CGFloat documentHeight = _totalHeight>NSHeight(bounds)?_totalHeight:(NSHeight(bounds) -2);
//Set the new height of the document view
[[self documentView] setFrame:NSMakeRect(0.0f, 0.0f, NSWidth([self contentViewRect]), documentHeight)];
}
and from -[PXListView layoutCell:atRow:]:
- (void)layoutCell:(PXListViewCell*)cell atRow:(NSUInteger)row
{
[[self documentView] addSubview:cell];
[cell setFrame:[self rectOfRow:row]];
[cell setListView:self];
[cell setRow:row];
[cell setHidden:NO];
[self setCell:cell expandedAtRow:row];
}
4. Setting _expanded to NO in -[PXListViewCell prepareForReuse]:
- (void)prepareForReuse
{
_dropHighlight = PXListViewDropNowhere;
_expanded = NO;
}
Note: In the sample PXListViewCell subclass, MyListViewCell, distributed with PXListView, the implementation of -[MyListViewCell prepareForReuse] fails to call [super prepareForReuse]. Make sure that this call is made in [TemplateListViewCell prepareForReuse]:
- (void)prepareForReuse
{
//...
[super prepareForReuse];
}
One change needs to be made to -[TemplateListViewCell toggleDetail:]. The line
[self setExpanded:isExpanded];
needs to be replaced by
[[[self listView] delegate] listView:[self listView] setExpanded:isExpanded atRow:[self row]];
Once you've set up your PXListView's delegate to properly handle the new delegate methods, you're ready to override [PXListViewCell setExpanded:] in your subclass TemplateListViewCell:
- (void)setExpanded:(BOOL)expanded
{
if (expanded) {
//add detail subviews
} else {
//remove detail subviews
}
[super setExpanded:expanded];
}
Replace //add detail subviews with your own code which programmatically adds the detail subviews that you want and replace //remove detail subviews with code to remove the detail subviews that you want, checking to see that they are present first.
You write
i want to add some extra contain (Controller) on it
It sounds like you want to add view controllers rather than views to your TemplateListViewCell. To do this, use an NSBox and set the box's contentView to your view controller's view. (For details on this, see this answer.)
If you plan on just showing a single view controller's view in an NSBox on the expanded TemplateListViewCell, you can just (1) add a property to TemplateListViewCell referencing your view controller and (2) add an NSBox to TemplateListViewCell xib and set its contentView to the appropriate view controller's view on [cell setExpanded:YES] and set its contentView to nil on [cell setExpanded:NO].
I'm trying to clean up the UI on my application (built for 10.5) and one thing that's rather annoying is that when I swap to the library I reload the contents and the nscollectionview that displays the items fades the old content out before fading the new ones in. I don't mind the fade in/out of old/new items, but the way i've programmed the view swapping should make the library reload happen before the the nsview that contains the nscollectionview is inserted into the main window.
Anyone had this sort of problem before?
Here's an abridged version of how the swap between different parts of the application to the library goes:
In the main controller:
-(void)setMainPaneToLibrary {
if(viewState == VIEW_STATE_LIBRARY)
return;
[libraryController refreshDevices:self];
[libraryController refreshLibraryContents];
[menuController setSelectionToIndex:0];
viewState = VIEW_STATE_LIBRARY;
[self removeSubview]; //clear the area
[mainPane addSubview:[libraryController view]];
}
In the library controller:
-(void)refreshLibraryContents {
[self loadLibraryContents:[rootDir stringByAppendingPathComponent:currentDir]];
}
-(void)loadLibraryContents:(NSString *)folderToLoad {
int i;
int currentSelection = [libraryArrayController selectionIndex]; //used to preserve selection and smooth folder changing
[libraryArrayController setContent:nil];
//expand the path to load
folderToLoad = [folderToLoad stringByExpandingTildeInPath];
NSFileManager * fileManager = [NSFileManager defaultManager];
//load the files in the folder
NSArray * contents = [fileManager directoryContentsAtPath:folderToLoad];
//create two seperate arrays for actual files and folders - allows us to add them in order
NSMutableArray * directories = [[NSMutableArray alloc] init];
NSMutableArray * musicFiles = [[NSMutableArray alloc] init];
//... a load of stuff filling the file arrays ...
for(i=0;i<[directories count];i++) {
[libraryArrayController addObject:[directories objectAtIndex:i]];
}
for(i=0;i<[musicFiles count];i++) {
[libraryArrayController addObject:[musicFiles objectAtIndex:i]];
}
if(currentSelection >= 0) {
[libraryArrayController setSelectionIndex:currentSelection];
}
[directories release];
[musicFiles release];
}
The issue is not that the collection view hasn't finished drawing, it's that it animates the adding and removal of the subviews. It may be possible to create a transaction that disables layer actions while you're reloading the collection view's content. Listing 2 (temporarily disabling a layer's actions) shows how to do this. I haven't tested this, so I don't know if this will do what you want, but this is where I'd start.