I have a simple collectionView, and with didSelectItemAtIndexPath and didDeselectItemAtIndexPath I change cell's background color.
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
cell.contentView.backgroundColor = [UIColor lightGrayColor];
}
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
cell.contentView.backgroundColor = [UIColor clearColor];
}
All works fine, but if I select a cell, scroll the list (my selected cell go out of screen) and I select another, in didDeselectItemAtIndexPath my "cell" variable is nil.
Why?
NB: only when the selected cell go out of screen
Simply logic behind cell selected and deselected in proper way:
ViewController.h
int selectedIndex;
ViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
selectedIndex = -1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *identifier = #"CollectionCell";
WalletCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
if(indexPath.row == selectedIndex)
{
cell.selected = YES;
cell.backgroundColor = [UIColor redColor];
}
else
{
cell.selected = NO;
cell.backgroundColor = [UIColor clearColor];
}
return cell;
}
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
selectedIndex = (int)indexPath.row;
cell.backgroundColor = [UIColor redColor];
}
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
cell.backgroundColor = [UIColor clearColor];
}
Related
I cannot seem to figure out why extra cells are being created and displayed when scrolling or sometimes when I dismiss another view controller to view the cells.
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger tmpIndex = indexPath.row+1; //addd 1 because userDetail is first element
if ([self.model.order[tmpIndex] isKindOfClass:[Products class]])
{
Products *products = [self.model.order objectAtIndex:tmpIndex];
if ([[products display] isEqualToString:kACTIVITY_GRID_CELL_ID])
{
ActivityCollectionViewGridCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kACTIVITY_GRID_CELL_ID forIndexPath:indexPath];
cell.data = products;
cell.delegate = self;
cell.tag = indexPath.row;
return cell;
}
else
{
ActivityCollectionViewListCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kACTIVITY_LIST_CELL_ID forIndexPath:indexPath];
cell.data = products;
cell.delegate = self;
cell.tag = indexPath.row;
return cell;
}
}
else
{
OrderHeaders *orderHeaderBaskets = [self.model.order objectAtIndex:tmpIndex];
ActivityCollectionViewListCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kACTIVITY_LIST_CELL_ID forIndexPath:indexPath];
cell.data = orderHeaderBaskets;
cell.delegate = self;
cell.tag = indexPath.row;
return cell;
}
}
To my understanding it only adds the extra empty cells for this part of the code:
else
{
ActivityCollectionViewListCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kACTIVITY_LIST_CELL_ID forIndexPath:indexPath];
cell.data = products;
cell.delegate = self;
cell.tag = indexPath.row;
return cell;
}
}
else
{
OrderHeaders *orderHeaderBaskets = [self.model.order objectAtIndex:tmpIndex];
ActivityCollectionViewListCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kACTIVITY_LIST_CELL_ID forIndexPath:indexPath];
cell.data = orderHeaderBaskets;
cell.delegate = self;
cell.tag = indexPath.row;
return cell;
}
Could this be because I am using dequeueReusableCellWithReuseIdentifier multiple times ? Or is something else causing this ?
Also is there a way to check and remove the extra cells?
I have a UICollectionView inside a UITableViewCell. You may refer the image at here
I would like to reload the collectionView if any update happen.
I have done some research and found this :
how to reload a collectionview that is inside a tableviewcell
Reloading collection view inside a table view cell happens after all cells in table view have been loaded
UICollectionView not updating inside UITableViewCell
I called the #IBOutlet weak var collectionView: UICollectionView! from UITableViewCell to UITableViewController at cellForRowAt.
Here is the code:
var refreshNow: Bool = false
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: Storyboard.allCardCell, for: indexPath) as! AllCardTableViewCell
if refreshNow {
cell.collectionView.reloadData()
refreshNow = false
}
cell.collectionView.collectionViewLayout.invalidateLayout()
return cell
}
If the user click Ok on UIAlertAction :
let alert = UIAlertController(title: "Success", message: "Card successfully added", preferredStyle: .alert)
let action = UIAlertAction(title: "Ok", style: .default) { (action) in
self.refreshNow = true
self.tableView.reloadData()
}
alert.addAction(action)
self.present(alert, animated: true, completion: nil)
The reason why I put the refreshNow is to prevent the apps from lagging and slow. But still did not update if any changes happen.
The problem is the collectionView did not refresh. But when I debug, it was went through the cell.collectionView.reloadData().
The update/changes only happen when I restart the apps. I want it to be so called real-times update.
Any help is really appreciated and many thanks.
Image credit: How to use StoryBoard quick build a collectionView inside UITableViewCell
At end of your update add:
DispatchQueue.main.async() { () -> Void in
self.tableView.reloadData()
}
In your case, you should assign tag to your collection view in order to get access outside the cellForRowAt function.
This is how your function should look like:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: Storyboard.allCardCell, for: indexPath) as! AllCardTableViewCell
cell.collectionView.tag = 1234
return cell
}
and the action will reload it will access the collectionView by using the tag
let action = UIAlertAction(title: "Ok", style: .default) { (action) in
let collectionView = self.tableView.viewWithTag(1234) as! UICollectionView
collectionView.reloadData()
}
Also take note that cellForRowAt will keep reload the content based what you added inside it every time the cell appear. So, keep updating your data outside the cellForRowAt function.
Because you reused UITableViewCell so you must alway reload your UICollectionView. If you use refreshNow to reload UICollectionView, at the cell have refreshNow = false, UICollectionView will display like cell that it 's reused => wrong
Udate rep:
See , in picture uitableviewcell 1 will reuse at index 6. If you not reload content of cell (reload collectionview) it will display like uitableviewcell 1 at index 0
#import "AddPhotoViewController.h"
#import "PhotoTableViewCell.h"
#import "ShareTableViewCell.h"
#interface AddPhotoViewController ()
#property (weak, nonatomic) IBOutlet UITableView *tblView;
#property (strong,nonatomic)NSMutableArray *arrImages,*arrIndexPath,*selectImages;
#end
#pragma mark - TableViewDelegate&DataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 3;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *returnCell;
static NSString *cellIdentifier = #"CellOne";
static NSString *cellIdentifierTwo = #"CellTwo";
static NSString *cellIdentifierThree = #"CellThree";
if (indexPath.row == 0) {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
returnCell = cell;
} else if (indexPath.row == 1){
ShareTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifierTwo forIndexPath:indexPath];
cell.viewMood.layer.cornerRadius = 5;
cell.viewPeople.layer.cornerRadius = 5;
[cell.viewMood layer].borderWidth = 1;
[cell.viewMood layer].borderColor = [UIColor colorWithRed:241.0/255.0 green:143.0/255.0 blue:48.0/255.0 alpha:1].CGColor;
[cell.viewPeople layer].borderWidth = 1;
[cell.viewPeople layer].borderColor = [UIColor colorWithRed:241.0/255.0 green:143.0/255.0 blue:48.0/255.0 alpha:1].CGColor;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
returnCell = cell;
}else if (indexPath.row == 2){
PhotoTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifierThree forIndexPath:indexPath];
cell.collView.dataSource = self;
cell.collView.delegate = self;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
returnCell = cell;
}
return returnCell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
return UITableViewAutomaticDimension;
}
#pragma mark- UIImagePickerControllerDelegate
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
UIImage *chosenImage = info[UIImagePickerControllerOriginalImage];
[_arrImages addObject:chosenImage];
PhotoTableViewCell *cell = [self.tblView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:2 inSection:0]];
[cell.collView reloadData];
[picker dismissViewControllerAnimated:YES completion:^{
}];
}
#pragma mark - CollectionViewDataSource
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return [_arrImages count];
}
- ( UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *cellIdentifier = #"CellCollection";
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
UIImageView *imgView = [(UIImageView*)[cell contentView] viewWithTag:100];
UIImageView *imgViewTick = [(UIImageView*)[cell contentView] viewWithTag:200];
UIView *view = [(UIView*)[cell contentView] viewWithTag:300];
if (indexPath.row == 0){
imgViewTick.hidden = YES;
view.hidden = YES;
}
if ([_arrIndexPath containsObject:indexPath]) {
[_selectImages removeAllObjects];
view.hidden = NO;
view.alpha = 0.4;
imgViewTick.hidden = NO;
imgView.image = [_arrImages objectAtIndex:indexPath.row];
[_selectImages addObject:[_arrImages objectAtIndex:indexPath.row]];
NSLog(#"Pick images:%#",_selectImages);
}else{
view.hidden = YES;
imgViewTick.hidden = YES;
imgView.image = [_arrImages objectAtIndex:indexPath.row];
}
return cell;
}
I add a image as avatar at indexPath [0,0], and use detailLabel display nickname at indexPath [0,1].
When use reloadRowsAtIndexPaths indexPath the indexPath [0,1] get a image...
I find when invoke reloadRowsAtIndexPaths the dequeue cell return nil.
Maybe the [0,0] cell be reuse at [0,1], I don't know why so that.
The code is:
- (void)viewDidLoad {
[super viewDidLoad];
_titles = #[#"Avator", #"Nickname"];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kDelayTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
_avator = [UIImage imageNamed:#"cat"];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kDelayTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
_nickName = #"Smallfly";
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:1 inSection:0];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];
});
});
}
#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return _titles.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *const cellIdenfier = #"cellIdentifier";
// Why reloadRowsAtIndexPaths [0,0] returned cell is nil?
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdenfier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdenfier];
}
if (indexPath.row == 0) {
[self configureCell:cell indexPath:indexPath];
} else {
NSString *nickName = _nickName ?: #"nickname";
cell.detailTextLabel.text = nickName;
}
cell.textLabel.text = _titles[indexPath.row];
return cell;
}
- (void)configureCell:(UITableViewCell *)cell indexPath:(NSIndexPath *)indexPath {
for (UIView *sv in cell.contentView.subviews) {
if ([sv isKindOfClass:[UIImageView class]]) {
[sv removeFromSuperview];
}
}
UIImage *avator = _avator ?: [UIImage imageNamed:#"user_profile_avatar"];
UIImageView *avatorImageView = [[UIImageView alloc] initWithImage:avator];
...
[cell.contentView addSubview:avatorImageView];
}
reloadRowsAtIndexPaths is a void method.
dequeueReusableCell always returns a cell (remove UITableViewCell alloc)
Objective-C
- (void)reloadRowsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths
withRowAnimation:(UITableViewRowAnimation)animation
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:#"reuseIdentifier"
forIndexPath:indexPath];
// Configure the cell...
return cell;
}
Swift 3
open func reloadRows(at indexPaths: [IndexPath],
with animation: UITableViewRowAnimation)
override func tableView(_ tableView: UITableView,
cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell =
tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier",
for: indexPath)
// Configure the cell...
return cell
}
You may want to look at a more recent tutorial or sample code.
I am loading cell from xib. But then table view controller opens the cell is white. And showing the labes and other stuff only after click on cell.
- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.delegate = self;
self.tableView.dataSource = self;
[self.tableView registerNib:[UINib nibWithNibName:#"FixedCell" bundle:nil] forCellReuseIdentifier:#"FixedCell"];
}
//cellForRow......
if(indexPath.section==1){
if(indexPath.row==0){
FixedCell *cell = [tableView dequeueReusableCellWithIdentifier:#"FixedCell"];
return cell;
}
}
Can anybody find it, what is wrong here?
Use this code it may help...
-(void)tableView:(UITableView *) willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
FixedCell *newCell = (FixedCell *)cell;
[newCell layoutIfNeeded];
}
Instead of loading the UINib inside UITableView just load it in viewDidLoad method..
Use this approach
UINib *nib = [UINib nibWithNibName:#"FixedCell" bundle:nil];
[self.tablView registerNib:nib forCellReuseIdentifier:#"FixedCell"];
Objective C
try this one...
cell =(FixedCell *)[tableView dequeueReusableCellWithIdentifier:#"FixedCell" forIndexPath:indexPath];
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(tableView.bounds), CGRectGetHeight(cell.bounds));
[cell layoutIfNeeded];
CGSize size = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
return size.height;
}
Swift:
var cell: FixedCell! = tableView.dequeueReusableCellWithIdentifier("FixedCell", forIndexPath: indexPath) as! HistoryTableViewCell
if (cell == nil) {
cell = FixedCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "FixedCell")
}
I have a UICollectionView that is populated by a UIImagePickerControl button that is in a Cell, I want the cell with the button to display the whole time, but I can't seem to get it to display.
Here is my code:
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return [self.project.screens count];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 1) {
Screen* screen = [self.project.screens objectAtIndex:indexPath.row];
static NSString* cellIdentifier = #"ImageCell";
CollectionViewCell *cell =[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
cell.screen = screen;
cell.delegate = self;
return cell;
}else{
static NSString* cellIdentifier = #"ButtonCell";
CollectionViewCell *cell =[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
cell.delegate =self;
return cell;
}
}
What should the code in my if statement be, and how do I add the +1 to the
return [self.project.screens count];
You are almost there, in
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
//Number of elements + 1 for the button
return [self.project.screens count]+1;
}
and in
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 1) {
Screen* screen = [self.project.screens objectAtIndex:indexPath.row];
static NSString* cellIdentifier = #"ImageCell";
CollectionViewCell *cell =[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
cell.screen = screen;
cell.delegate = self;
return cell;
}else{
static NSString* buttonCellIdentifier = #"ButtonCell";
CollectionViewCell *cell =[collectionView dequeueReusableCellWithReuseIdentifier:buttonCellIdentifier forIndexPath:indexPath];
cell.delegate =self;
return cell;
}
}