I have a custom UICollectionVIewCell. When the user selects a cell I want the border of the cell to be Red in color and when the user de-selects it I want to clear-color the border of the cell.
How is this possible?
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
CustomeCollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
cell.backgroundColor=[UIColor redColor];
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath{
CustomeCollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
cell.backgroundColor=[UIColor clearColor];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cellIdentifier" forIndexPath:indexPath];
NSString *img =[[images objectAtIndex:indexPath.row]valueForKey:#"imageName"];
cell.backgroundView=[[UIImageView alloc]initWithImage:[UIImage imageNamed:img]];
cell.layer.borderWidth=10;
cell.layer.borderColor=[UIColor greenColor].CGColor;
return cell;
}
This is working code in my app. Make sure that there is borderwidth if you giving bordercolor.
Use built in methods of UICollectionViewCell class.
You need override setHighlighted: method.
- (void)setHightlighted:(BOOL)highlighted {
[super ....];
self.something = highlighted ? red : blue;
}
You can try:
cell.layer.borderColor
to change color border
Related
When I select a cell, it turns blue, which is good. Then when I scroll up and the cell out of view, it turns back to original color. Not sure how to fix this.
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cellIdentifier" forIndexPath:indexPath];
cell.backgroundColor=[UIColor lightGrayColor];
[collectionView selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone];
self.collectionView.allowsMultipleSelection=YES;
return cell;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor blueColor];
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
}
In your first method, you are practically telling the collection view to select any cell that it asks for. Instead, you should check whether the cell you return has the same path as the selected one, and only then give it color:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cellIdentifier" forIndexPath:indexPath];
if ([indexPath isEqual:self.selectedIndexPath]) // you need to create selectedIndexPath as a property
{
cell.backgroundColor=[UIColor blueColor];
}
else
{
cell.backgroundColor=[UIColor lightGrayColor];
}
return cell;
}
And then:
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
self.selectedIndexPath = indexPath;
}
When cell are reused, the selection state is lost. So you need to save the indexPath of the selection in didSelectItemAtIndexPath. And when you dequeue the cell you need to check and restore the state
I can change my collection view cell background color in cellforitematindexpath but not in didselectitematindexpath using the code below (i only change the color in one place however). How does this happen? I know that didselectitematindexpath is being called.
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
CollectionViewCell *cell = [cv dequeueReusableCellWithReuseIdentifier:#"CollectionView" forIndexPath:indexPath];
cell.layer.borderWidth=1.0f;
cell.layer.borderColor=[UIColor grayColor].CGColor;
cell.label.text = #"test"
cell.contentView.backgroundColor = [UIColor redColor];
return cell;
}
-(void)collectionView:(UICollectionView *)cv didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"selected cell");
CollectionViewCell *cell = [self collectionView:cv cellForItemAtIndexPath:indexPath];
cell.contentView.backgroundColor = [UIColor redColor];
}
Several things wrong here.
You're using the wrong method to get the selected cell. Never call the delegate method directly, instead ask the collection view for the cell directly like this:
CollectionViewCell *cell = [cv cellForItemAtIndexPath:indexPath];
You're modifying the cell in a place where those modifications will not persist. When you scroll and that cell gets reused, the color will get wiped out. Instead you should call reloadItemsAtIndexPaths: when the cell gets selected, and have some code in collectionView:cellForRowAtIndexPath that checks the selected property of the cell and sets the color you want based on that. That way, the layout will remain consistent when you scroll and cells are reused.
use this..
self.collectionView.allowsMultipleSelection = YES;
then..
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath**
{
static NSString *identifier = #"Cell";
RecipeViewCell *cell = (RecipeViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];
recipeImageView.image = [UIImage imageNamed:[recipeImages[indexPath.section] objectAtIndex:indexPath.row]];
cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"photo-frame-2.png"]];
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"photo-frame.png"]];
return cell;
}
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
if (shareEnabled) {
NSString *selectedRecipe = [recipeImages[indexPath.section] objectAtIndex:indexPath.row];
[selectedRecipes addObject:selectedRecipe];
}
}
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
if (shareEnabled) {
NSString *deSelectedRecipe = [recipeImages[indexPath.section] objectAtIndex:indexPath.row];
[selectedRecipes removeObject:deSelectedRecipe];
}
}
I want ot set a border to a selected cell, i save a cell property that represents the selected one and manipulate it:
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
NSArray *eyeArray = [self eyesArrayConfigure][indexPath.row];
if (indexPath.row==5) {
int r = arc4random() % 6;
eyeArray = [self eyesArrayConfigure][r];
}
[borderedCell.contentView.layer setBorderWidth:0.0f] ;
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
borderedCell = cell;
[borderedCell.contentView.layer setBorderColor:self.view.tintColor.CGColor];
[borderedCell.contentView.layer setBorderWidth:3.0f];
}
and the cellForView: (Im usinng 2 types of cell identifiers because one cell contains a label - "Random cell":
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.row ==5) {
UICollectionViewCell *randomCell =[collectionView
dequeueReusableCellWithReuseIdentifier:#"randomCell"
forIndexPath:indexPath];
randomCell.backgroundColor = [UIColor purpleColor];
borderedCell = randomCell;
[borderedCell.contentView.layer setBorderColor:self.view.tintColor.CGColor];
[borderedCell.contentView.layer setBorderWidth:3.0f];
return randomCell;
}
UICollectionViewCell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
NSArray *eyeArray = [self eyesArrayConfigure][indexPath.row];
myCell.backgroundView = [[UIImageView alloc] initWithImage:eyeArray[1]];
return myCell;
}
What i get is if a click one cell it will be fine till i scroll and then i get weird behaviour when couple of cells might be with the border.
Thanks for the help.
The solution is to use a view model. You are already doing this for your cells' background views. Apply the same concept for the border.
#interface MyCollectionView ()
#property (nonatomic) NSInteger selectedRow;
#end
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
//update self.selectedRow and either reload entire collection view or just the currently selected and previously selected.
self.selectedRow = indexPath.row;
[collectionView reloadData];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
CGFloat borderWidth = (indexPath.row == self.selectedRow) ? 3.0 : 0.0;
[myCell.contentView.layer setBorderWidth:borderWidth];
return myCell;
}
I am trying to use this code, but it's not working:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
printf("Selected View index=%d",indexPath.row);
UICollectionViewCell *cell = [self.collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
cell.selectedBackgroundView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"blue_s.png"]];
//[self.collectionView reloadData];
}
How do I change the UIImage of selected UICollectionViewCell in a UICollectionView?
did using this
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [self.collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
cell.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"yellow_seat.png"]];
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"blue_s.png"]];
return cell;
}
got help from link
try this
UICollectionViewCell *cell = (UICollectionViewCell *)[self.collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
I am trying to highlight a selected collection cell in UICollectionView with yellow border so user can see which one is currently selected. I tried this:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
FilterCell *filterCell = (FilterCell *)[collectionView dequeueReusableCellWithReuseIdentifier:#"FilterCell" forIndexPath:indexPath];
filterCell.window.backgroundColor = [UIColor yellowColor];
filterCell.backgroundColor = [UIColor yellowColor];
NSLog(#"hello");
}
There are 2 empty pixels around UIImageView inside UICollectionViewCell so it should work but it doesn't.
It is logging "hello" but the border stays black. See this screenshot:
You are getting the cell in the wrong way
FilterCell *filterCell = (FilterCell *)[collectionView dequeueReusableCellWithReuseIdentifier:#"FilterCell" forIndexPath:indexPath];
will dequeue a cell which is not used right now or allocate a new one with the specified identifier.
Use
FilterCell *filterCell = (FilterCell *)[collectionView cellForItemAtIndexPath:indexPath];
instead.
Anyway a cleaner solution would be to set the backgroundView and selectedBackgroundView properties of the cell, without touching the backgroundProperty color (that will stay clear as default). In this way you can avoid the delegate method and achieve the same behavior.
Do a reloadItemsAtIndexPaths: there instead, then in cellForItemAtIndexPath, check if [[collectionView indexPathsForSelectedItems] containsObject:indexPath] If true, change the cell's attributes there.
This may help you:
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"YOUR_FILE_NAME.png"]];
-This code may help you to change background colour of selected cell
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cvCell" forIndexPath:indexPath];
if (cell.selected) {
cell.backgroundColor = [UIColor blueColor]; // highlight selection
}
else
{
cell.backgroundColor = [UIColor redColor]; // Default color
}
return cell;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor blueColor]; // highlight selection
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor redColor]; // Default color
}