I have a collection view with more sections, so how to set the number of cell in section in collection view. Thank for help
// Hi Please fallow this code it may help you
// This collectionView delegate method defined number of section we need
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 2;
}
/* This collectionView delegate method for define number of cell need to return in section
*/
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
if (section == 0)
{
return 10;
}
else
{
return 20;
}
}
You can use the method:
– numberOfItemsInSection:
Or you can refer:
https://developer.apple.com/library/ios/documentation/uikit/reference/UICollectionView_class/Reference/Reference.html#//apple_ref/doc/uid/TP40012177-CH1-DontLinkElementID_5
for UICollectionView details...
Related
I have UICollectionView and I would like to put a another Header as sample below (dark blue color).
In numberOfSectionsInCollectionView, I able to get the dynamic header 1 & 2 and CollectionView Cell if I use distinctNames.count. and return [groups[section][#"infos"] count]; in numberOfItemsInSection.
My question is, how can I add in extra header (something like static header as below) / cell in numberOfSectionsInCollectionView / numberOfItemsInSection if I have another section and cell to add in?
Can I use return distinctNames.count + 1; for additional header? And how can I set in numberOfSectionsInCollectionView?
Please help. Thank you.
- (NSInteger) numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return distinctNames.count + 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
if (section == 0) {
return 1;
}
}
return [groups[section][#"infos"] count];
}
I'm trying to make a UITableView present a determined number of rows for a section, but even when I verify that its data source is returning x number of rows for numberOfRowsInSection, the table view shows x-1.
The exception to this unexpected behavior is if the numberOfRowsInSection is less than 3.
I've even put a breakpoint in cellForRowAtIndexPath and I confirmed it's being called for the row that is not appearing.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (section == SectionNumber_One) {
return 6;
} else {
return self.numberOfProjectRows; // This returns x, but x-1 rows are being shown
}
}
For example, if self.numberOfProjectRows is 5, only 4 rows are shown for the second section.
If I increase it manually to 6, it shows 5 rows but the data that should be in the 5th position, isn't there.
It doesn't seem to be related to screen size as I tested it on an iPad with same results.
Why is this happening? Is there some other possible modifier of the number of rows in a section?
I'm attaching an screenshot if it's of any help.
EDIT - Here are my delegate methods:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Cell with reuse identifier setup
if (section == SectionNumber_One) {
// cell setup for section one that's showing up ok
} else if (section == SectionNumber_Two) {
UITextField *projectField = cell.projectTextField;
if ([self.userProjectKeys count] > row) {
projectField.text = self.availableProjects[self.userProjectKeys[row]];
}
}
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
// Hide the password row for existing users
if (indexPath.row == FieldTag_Password && ![self.user.key vol_isStringEmpty]) {
return 0.0f;
} else {
return UITableViewAutomaticDimension;
}
}
The problem is probably not in your Datasource methods, but your Delegate methods, tableView(_:heightForRowAt:).
If you do not return a correct height for the cell, it won't show up.
It doesn't matter if you write 1000 cells in your datasource. If you don't return the height, they wont show up.
You are not comforming to the MVC pattern in implementing the table. You must return the count of the tableView's datasource, not variables of it.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (section == SectionNumber_One) {
return 6;
} else {
return [_displayingArray count]; // <-- here
}
}
If you want different items for each sections, then declare different datasource (ie array) for each of them.
EDIT: Even returning constant 6 is dangerous in the other section - you ought to add items to another fixed array and return that array's count in this delegate.
I have several sections in a uitableview as shown here:
How do I hide the first section header e.g. Men.
Try overriding GetHeightForHeader in UITableViewSource, and returning 0 it's the first section
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
if (section == 0) return 0;
return tableView.sectionHeaderHeight;
}
In Xamarin, it would look like:
public override float GetHeightForHeader (UITableView tableView, int section)
{
if (section == 0)
return 0;
return tableView.SectionHeaderHeight;
}
I'm kinda newbie in UICollectionView and I'm working in a project that dynamically changes the UICollectionViewLayout in a given action.
My CollectionView has 6 sections, each of them with 10 elements. Those Cells are basically an UIImageView and my Custom Layout called StackViewLayout stacks all elements for each section (something like Apple's Photos.app).
If the user selects the element of the stack (for all sections), the UICollectionView dynamically changes the layout to the UICollectionViewFlowLayout, so all the elements can be viewed as grid.
My problem is that when user selects a stack, no matter which section, when the Layout is changed do Flow Layout, all sections are displayed in the grid, instead of displaying the elements for the selected section (stack), which is the behavior I wanted.
Is there any way to show only the Flow Layout for the selected section in the Custom Layout?
Here is my Controller Implementation snippet code:
- (void)viewDidLoad
{
[super viewDidLoad];
[self loadStackLayout]; // stack all sections at first load.
}
#pragma mark - UICollectionView Data Source Methods
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 6;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 10;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;
{
// custom UICollectionViewCell, which will hold an image.
CVCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"MyCell" forIndexPath:indexPath];
cell.imageView.image = _images[indexPath.row];
return cell;
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
// element size.
return CGSizeMake(100,100);
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
if (isStacked)
{
[self loadFlowLayout]; //HERE I WANT TO LOAD FLOW LAYOUT ONLY FOR THE SECTION OF THE SELECTED ITEM!
} else
{
// to implement.
}
}
// HERE IS THE METHOD THAT CALLS MY CUSTOM LAYOUT IN ORDER TO STACK THE ELEMENTS FOR EACH SECTION IN COLLECTION VIEW. IT IS WORKING AS IT SHOULD.
-(void)loadStackLayout
{
if (([self.collectionView.collectionViewLayout isKindOfClass:[UICollectionViewFlowLayout class]]))
{
isStacked = YES;
[self.collectionView setCollectionViewLayout:[[StackViewLayout alloc] init] animated:YES];
}
}
// HERE IS THE METHOD THAT CALLS MY FLOWLAYOUT IN ORDER TO UN-STACK THE ELEMENTS AND SHOW THEM IN A GRID. CURRENTLY IT IS SHOWING ALL SECTIONS IN THE GRID.
-(void)loadFlowLayout
{
if (([self.collectionView.collectionViewLayout isKindOfClass:[StackViewLayout class]]))
{
isStacked = NO;
[self.collectionView setCollectionViewLayout:[[UICollectionViewFlowLayout alloc] init] animated:YES];
}
}
I think you can probably do it by having an if clause in your numberOfItemsInSection: method, to return 0 for any section that's not the selected one. Obviously, you'll need to keep track of the selected section to do this.
I have a UICollectionView which utilizes a custom UICollectionViewCell class. The basic idea is the collection view will traverse directories and display photos contained within the directory (results via API calls). The initial view controller displays a UICollectionView, and taps on the cells generates a new view with a new UICollectionView. The directory contents are stored in an NSMutableDictionary with the directory ID being the key.
The problem occurs when a new view/collectionview is created with a rather short list of photos -- usually less than 30. When I rotate the device, the collection view attempts to re-render, and the app crashes with a "index X beyond bounds [0 .. Y]", with X being a number larger than Y (the last element of the array).
I've noticed this tends to only happen when the newly displayed collection view has less items than the "root" collection view.
Here are examples of the relevant (some of it, anyway) code:
- (NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section {
return [[photos objectForKey:api.directoryID] count];
}
- (NSInteger)numberOfSectionsInCollectionView: (UICollectionView *)collectionView {
return 1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
PhotoCell *photoCell = [cv dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
photoCell.photo = [[photos objectForKey:api.directoryID] objectAtIndex:indexPath.row];
return photoCell;
}
At the very least, I'd like to do a try/catch on the cellForItemAtIndexPath, but don't know where I would put the try/catch. Perhaps in a custom UICollectionView?
Thanks!
The problem is here:
- (NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section {
return [[photos objectForKey:api.directoryID] count];
}
I assume, you use one delegate and dataSource object for all of your UICollectionView instances.
If so, rewrite your code in this manner:
- (NSInteger)collectionView:(UICollectionView *)view
numberOfItemsInSection:(NSInteger)section
{
if ( view == _firstCollectionView )
{
return [[photos objectForKey:api.directoryID] count];
}
else if ( view == _secondCollectionView )
{
return ...;
}
}
Also you should rewrite collectionView:cellForItemAtIndexPath: method in such way.