I have a fixed number of Sections in a UICollectionView
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
return 3;
}
and a fixed number of items per section
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return 9;
}
The first 9 items are properly displayed through a plist (with cellForItemAtIndexPath) in the first section. However the second and third sections only display the items from the first section, instead of displaying the required items.
So, I'm trying to display all the items from the plist, and have them grouped automatically into sections (of 9 items).
I'm fairly new to Objective-C and have been struggling with this for quite a while, so I'd really appreciate your help.
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
xx.image = [UIImage imageNamed:[imagePath objectAtIndex:indexPath.item]];
}
You can try this way.
You need to specify indexpath this way.
xx.image = [UIImage imageNamed:[imagePath objectAtIndex:indexPath.section * number of sections + indexpath.row]];
Hope this helps you.
Judging by "the second and third sections only display the items from the first section" I would think you are incorrectly identifying the section number (maybe ignoring it altogether?) in your cellForItemAtIndexPath. Please add this method to the question, because the problem is most likely there.
Related
In one section of my app I have a UITableView which is working fine right now. I would like to set row 0 cell.textLabel.text to #"Some string". Once row 0 has been set I would then like to load the rest of the rows from an array. Currently on load my array populates the table view but I'm trying to set row 0 as a sticky. The closest example I can think of is a forum topic that is set to stay at the top. My array is constructed of returned data from a web service call.
It's been a while since I've messed with table views, and I'm having a blank on this one.
The table view is 1 section, and I get the rows by counting the elements in the array. Since I would like to create an additional cell (row 0) I would call [array count] + 1. I don't know if this approach is the best one which is why I'm reaching out to the community here.
Any insight or a shove in the right direction would be great at this point.
You're on the right track:
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [array count]+1;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if ([indexPath row] == 0) {
// Code for first
[[cell textLabel] setText:#"First cell"];
} else {
[[cell textLabel] setText:[array objectAtIndex:[indexPath row]-1]];
}
return cell;
}
If you want the top of your table to be "sticky", why not consider using that string as a section header or title? In this case, the header stays visible at all times until the next section (e.g. if you had two sections, that is) is fully on the screen.
In any event, in one of my current projects I'm required to do roughly the same thing that you're doing and I have a static string being returned in row 0 (which scrolls off the top of screen when the table view scrolls down).
And in my UITableViewDataSource method, I always add one for the static cell to the number of objects in my array and in my "cellForRowAtIndexPath:" method, I increment the row by one when the indexPath.row is not zero. And if it is zero, I return my static string.
And dark_knight provides some nice sample code that illustrates what I was describing to you. So +1 to him/her.
How can I programmatically add or remove a cell from a grouped section?
I created a grouped tableview using static cells in storyboard. Inside the storyboard I set the number of rows using the Attribute Inspector panel. For example, for section 1, I define 3 rows. Then using an NSMutableArray of 3 items, I can properly load values into each section correctly at startup.
I ultimately want the ability to add/remove a cell at runtime. That part hasn't been coded yet but to simulate adding a new cell scenario, I added a new item to the array in the code but did not increase the row count for the section in the Attribute Inspector panel. I had hoped that I would not need to make any other changes to accomodate the new item since inside the numberOfRowsInSection method, I'm returning the count of the array for the specific section.
This is the error message that I get when I re-ran the code:
* Terminating app due to uncaught exception 'NSRangeException', reason: '* -[__NSArrayI objectAtIndex:]: index 3 beyond bounds [0 .. 2]'
Apparently I need to somehow specify an additional row count. Can anyone shed some light on how I can do this at runtime? Thanks.
You should not do it through attribute inspector. it abstains you to do dynamic insertion and deletion of cells.
try
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [yourArray count];
}
else do this.
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
if(section==0){
return 3;
}else if(section==1){
return 4;
}
return 0;
}
and so on for different section if u have many section..
you can reload the whole table when you array from which data is read is updated..
[tableView reloadData];
but a better way to do it is to insert row or multiple rows like this in a block.
[tableView beginUpdates];
[tableView insertRowsAtIndexPaths:yourIndexPath withRowAnimation:UITableViewRowAnimationRight];
[tableView endUpdates];
you can also add animation to add cell from right or lect or top or bottom.
I hope this helps you!!
Cheers!!
I guess that you hardcoded the number of rows for your section. Because looking at the error it seems that your section is expecting 4 object but your data source contains only 3.
Inside your :
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
you should return something like [myArray count], so adding or delting rows shouldn't be a problem if you add or remove the object from your array.
You have Predefined methods in UITableview for Inserting and deleting row, For insertion we can user insertRowAtIndexPath method and for deletion use deleteRowAtIndexPath methods.
I want my tableView to show 6 rows with text in it, in this case "Example." As far as I can tell, I have my numberOfSectionsInTableView: and numberOfRowsInSection: set properly. See example code below:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
// Return the number of rows in the section.
return 6;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = #"Example";
return cell;
}
The problem is when you see the image below showing lines for rows that shouldn't/don't exist.
How do I get rid of the lines showing past row 6?
The generally accepted way of doing this is to add a footer view with a frame size of CGRectZero, as such:
[tableView setTableFooterView:[[UIView alloc] initWithFrame:CGRectZero]]
What this does is tell the table that there is a footer, and so it stops displaying separator lines. However, since the footer has a CGRectZero as its frame, nothing gets displayed, and so the visual effect is that the separators simply stop.
Swift Version
The easiest method is to set the tableFooterView property:
override func viewDidLoad() {
super.viewDidLoad()
// This will remove extra separators from tableview
self.tableView.tableFooterView = UIView(frame: CGRect.zero)
}
This is Because of Your Table-view Height. Weather you have Write
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
// Return the number of rows in the section.
return 6;
}
But its show rows According to Table-view Size. If you Dont want to show This extra Lines then Make UITableView Style Plain To Grouped.
Short and simple answer..
self.tableView.tableFooterView = [UIView new];
You could do something along the lines of:
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:7 inSection:0];
[self.mytableView cellForRowAtIndexPath:indexPath].hidden = YES;
Im sure there are some better ways but this is the first thing that came to mind.
If you're referring to the light gray lines that appear below the last row, that's simply the default way a UITableView draws the row separator.
You could try changing the Separator style in Interface Builder (see the images below) to see if one of those might be more to your liking.
You didn't say what you do want to see past the last row. If you just want to see the window background, then just embed your table view in a UIView that's just tall enough to show the number of rows you want to see. If you want to see more rows without scrolling, then you would have to adjust the size of that containing view based on the number of rows.
To programmatically remove it, use this:
[yourTableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];
It's a lot easier to:
return numberOfSections + 1
return 0 rows in the final section
This keeps it simple!
How do i display set number of rows in a UITableView?
i.e if my data source has only 4 objects then i want the table to display on those 4 rows without any blank rows. any ideas?
thanks!
EDIT: i wasn't too clear about the question so..
So this is my table: http://i.stack.imgur.com/glkWZ.png ..
i want to display only the 3 rows and not the blank rows below it. The number of rows change depending on my data source.
any ideas how to go about doing so?
You have to change your table appearance, I think. Once you correctly set the numberOfSectionsInTableView: and tableView:numberOfRowsInSection: methods, you should change your viewDidLoad method adding this line:
[self.tableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];
This way you will remove all lines from the table.
If you still want to make a line appear between lines, I suggest you to create a custom UITableViewCell, or to build a standard one adding a subview to mimic the line. Eg. something like this:
CGRect lineFrame = CGRectMake(0,cell.frame.size.height-1,cell.frame.size.width,1);
UIView *line = [[UIView alloc] initWithFrame:lineFrame];
line.backgroundColor = [UIColor colorWithRed:0.9 green:0.9 blue:0.9 alpha:1];
[cell.contentView addSubview:line];
[line release];
Let me know if this helps.
Check the UITableView DataSource protocol, there are two relevant methods you have to implement:
– numberOfSectionsInTableView:
– tableView:numberOfRowsInSection:
The first one should return 1, the second one 4.
If you want to keep a set number of lines in your tableview and not display the extra blank lines, you could insert a empty footer view in viewdidload function.
self.tableview.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];
I did not actually understand what you mean with "display on those 4 rows without any blank rows" but I guess what you ask is just a simple data retrieval process. I suppose the data source is NSarray.
-numberOfRowsInSection:(NSInteger)section{
return [MyArray count];
}
-cellForRowAtIndexPath(NSIndexPath*)indexPath{
NSInteger row=indexPath.row;
cell.textLabel.Text=[MyArray objectAtIndex:row]
return cell;
}
I assume you know what should be put in those blank spaces.I just wrote the major points.
try this
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 4
}
also implements the rest of delegate methods required to populate tableview..
Hope it helps you.......
You can use this
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 4
}
Or you this also
Check the UITableView DataSource protocol, there are two relevant methods you have to implement:
– numberOfSectionsInTableView:
–
tableView:numberOfRowsInSection:
The first one should return 1, the second one 4.
Or you can also use
GroupBy table in your view by changing the table style to gourpby table. use
The standard Grouped UITableView style allows UITableViewCells to be drawn with rounded corners at the top and bottom of each section. How is this accomplished? How does the cell know its own location within its section, and how does it know when to change its rounded edges?
I want to make my own rounded cells, and I have images to use, but don't know when to show which image
Note: I already know how the UITableView works, and I know how to use it. I just thought that since a UITableView is able to automatically draw rounded corners at the correct places, I should be able to as well, without needing to add anything to my data source or delegate.
NSIndexPath *indexPath = [(UITableView *)self.superview indexPathForCell: self];
int rows = [(UITableView *)self.superview numberOfRowsInSection:indexPath.section];
if (indexPath.row == 0 && rows == 1) {
// the one and only cell in the section
}
else if (indexPath.row == 0) {
//top
}
else if (indexPath.row != rows - 1) {
//middle
}
else {
//bottom
}
It's very simple. suppose cell is the object, whose position is to be found out.
UITableView* table = (UITableView *)[cell superview];
NSIndexPath* pathOfTheCell = [table indexPathForCell:cell];
NSInteger sectionOfTheCell = [pathOfTheCell section];
NSInteger rowOfTheCell = [pathOfTheCell row];
There is sectionLocation method of UITableViewCell that returns integer telling you what you need:
1 - middle cell
2 - top cell
3 - bottom cell
4 - single cell
I had no issues using this in several production apps since 2010.
UPDATE: one of our binaries was automatically rejected recently (end of 2018) because we were using 'sectionLocation' property, so it's not a good option anymore.
Add something like this into your header files and you can use it:
typedef NS_ENUM(NSInteger, MMMTableViewCellLocation) {
MMMTableViewCellLocationUndefined = 0,
MMMTableViewCellLocationMiddle = 1,
MMMTableViewCellLocationTop = 2,
MMMTableViewCellLocationBottom = 3,
MMMTableViewCellLocationSingle = 4
};
#interface UITableViewCell ()
/** Undocumented method of UITableViewCell which allows to know where within section the cell is located,
* so the cell can draw its borders properly. */
- (MMMTableViewCellLocation)sectionLocation;
/** Override this one to know when the value of sectionLocation changes. */
- (void)setSectionLocation:(MMMTableViewCellLocation)sectionLocation animated:(BOOL)animated;
#end
You can use
- (NSIndexPath *)indexPathForCell:(UITableViewCell *)cell
for this issue. In my example I am using this to scroll the cell (with custom content) to the top of the view.
If you need more robust and general stuff, take a look at http://cocoawithlove.com/2009/04/easy-custom-uitableview-drawing.html - Matt Gallagher shows what you need, pretty effectively. He basically recreates UITableViewController from UIViewController, while adding ability to use your own custom graphics. I'm just working on applying this to one my projects, so far it looks it would do the job.
Unfortunately, I have found no solution to this problem, and have resorted to subclassing UITableViewController and UITableViewCell into a generic solution that I can extend as necessary.
You don't do this in cell. Rounded corners are drawn in [tableView viewForHeaderInSection] and viewForFooterInSection.
The way I do it is to use Plain tableview style, then use these two views for roundness and cells are normal, no rounds.
Without getting into who draws what, you can know which cell is the last cell in its section inside of cellForRowAtIndexPath very easily.
You're passed in the indexPath of the cell you need to provide, right? You're also passed the tableView.
call [tableView numberofRowsInSection:indexPath.section] and if it's == ([indexPath.row]-1) you know you're being asked to supply the last cell in that section.
At the time that cellForRowAtIndexPath is being called, the cell is guaranteed to be at the indexPath passed in.
To expand upon Darren's answer (which I found most useful, thanks Darren!), what you can do is to iterate through all of the superviews' until you find the parent UITableView. This should be future proof since you do not rely on a fixed hierarchy of views.
I use a recursive method that will return the UITableView if it finds one or return nil if there is none.
- (UITableView *)parentTableViewOf:(UIView *)view {
Class class = [view.superview class];
NSLog(#"Class : %#", NSStringFromClass(class));
if([view.superview isKindOfClass:[UITableView class]]) {
return (UITableView *)view.superview;
} else {
return [self parentTableViewOf:view.superview];
}
return nil;
}
So far I've used this one and it seems to work without hiccups. Hope it helps! :)
The cells dont know where they go...The table view has cells, You are the one telling the table view WHAT goes in the cell. You do this in the DataSource where you implement cellForRowAtIndexPath...The way this works :
An index path has a row and a section
For a grouped table view
A section pertains to a group, and a row pertains to 1 entry in that section,
the way UITableView knows how many rows are in a section and how many sections there are is the DataSources methods numberOfSectionInTableView and the method numberOfRowsInSection, this will make the right calls to cellForRowAtIndexPath, it is up to you to recognize which section and row is being queried and you need to build your cell according to these specifications.
A good way to do this i s you can have a Dictionary with keys of section names and values of NSArray with the values that go in that section.
So you implementation for numberOfSectionsInRows would look like
return [[dictionary allKeys] count]
And the implmentation of numberOfRowsInSection would look like
NSString* key=[[dictionary allKeys] objectAtIndex:sectionNumber]
return [[dictionary objectForKey:key] count]
You can always refer to the UITableView programming guide at http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/TableView_iPhone/Introduction/Introduction.html
Hope that helps
Simply add a property to your custom UITableViewCell (depending on implementation) class that contains an int, NSNumber, or an NSIndexPath specifying which one it is. In you're using a data structure instead, then put it in you element in that data structure. Then you simply set the property when you create the data structure, something like elt.id=i, and then you access it in the cellForRowAtIndexPath, something like if (elt.id == 0 || elt.id == n-1) where n is the number of rows in your section.
I might have totally missed your question, but if I did, just comment and I'll post again.