I have list of complex UIViewControllers. This list should be displayed in vertical form. I'm wondering how can I display them. I tried UIPageViewController, but it's showing just one child controller. I need to show them as many as can fit on screen (like UITableView or UIScrollView). I cannot use UITableView, because it doesn't support nested UIViewControllers. So do I have to use UIScrollView and implement own releasing mechanism for child controllers or is there any other way?
You can use UITableView:
in tableViewDelegate put
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
//calc cell height
return height;
}
than in this method do like there:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:COMMON_CELL_IDENTIFIER];
[self addChildViewController:viewControllers[indexPath.row]];
[cell.contentView addSubview:[viewControllers[indexPath.row] view]];
return cell;
}
Related
I am trying to work with UICollectionView that is a part of the UITableViewCell.
So the issue I faced, the collection view for visible table cells works ok, but when I start scroll table and table starts create new cells that where invisible then I faces with some behaviour that duplicate first table cell. For example I have scrolled collection view in first table view cell, then I scrolled table view down, and what I see the new cell have the same state as my first cell had. You can check source here repo and the video here to understand what I am talking about.
Have a property of UICollectionView in CustomTableViewCell.h and bind it in Main.storyboard. Let's assume declared it like this:
#property (strong, nonatomic) UICollectionView *collectionView;
In ViewController.m change cellForRowAtIndexPath method, so it reloads inside UICollectionView every time it need
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
CustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"CustomTableViewCell"];
[cell.collectionView reloadData];
[cell.collectionView scrollRectToVisible:CGRectZero animated:NO];
return cell;
}
Of course, you need to import CustomTableViewCell.h on ViewController.m file.
-[UITableViewCell prepareForReuse]
Problem with reuse identifier in UITableView cell, if you use single cell identifier in cellForRowAtIndexPath this problem will occurs
1. Use Dynamic cell identifier for each row, like this
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
CustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:[NSString stringWithFormat:#"CustomTableViewCell_%d",indexPath.row]];
}
2.Store content offset for each collection view in array, and reset collection view content offset
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
......
[cell.collectionView setContentOffset:scrollingPoint animated:NO];
return cell;
}
I have gif animated pictures in some uitableview rows,
When there is a lot of gifs in tableview CPU usage is going to be very high,
So I want to hide these gifs when their row is not visible,
How can I do that ?
How can I achieve not visible cells row's indexPath ?
After that I can hide the gif like that :
UITableViewCell *celll = [ tableView cellForRowAtIndexPath:indexPath];
UIImageView *gif = (UIImageView*)[celll viewWithTag:30000];
gif.hidden = TRUE;
So I must get not visible cells indexPath's in a loop.
Generally, you don't need to do that as long as you properly use reusable cells.
Nevertheless, if you do want to do that, you can use tableView:didEndDisplayingCell:forRowAtIndexPath: method on UITableViewDelegate:
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell
forRowAtIndexPath:(NSIndexPath *)indexPath {
UIImageView *gif = (UIImageView*)[celll viewWithTag:30000];
gif.hidden = YES;
}
If you'll put the line:
NSLog(#"%#",indexPath);
as the first line of the method:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
You'll realise that it's done automatically. Only the visible cells, i.e the one that appears on the screen, are the one you present the data for.
Sorry for poor english.You had not posted code about how your cellForRowAtIndexPath implementation look like,i will suggest to make your cellForRowAtIndexPath like below.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"YOURIDENTIFIERSTRING";
UITableViewCell *cell = [tableView dequeReusableCellWithIdentifier: CellIdentifier forIndexPath:indexPath];
// Configure the cell here …
return cell;
}
This way only those many cells will be created which are visible on device and once row goes out of device view it will be reuse for new row. Please check apple doc for tableview.
i don no whether this question asked or not but i still searching for an answer.Am working in tableview concept and i am creating a table view like with some set of menu's like inbox, sent,setting etc.Now what i want is i want to create sub menu's inside every menu, for example if i click inbox it should show new,replied,deleted etc like this for every main menu i want to create sub menu. Using array we can load by checking section but with out using array i want to create directly and notable one i have used custom cell i also want to show images as per the menu if it is inbox i have to show inbox image. Could any one help me??
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 8;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 8;
}
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellidentifier=#"ViewProfileCell";
MyHomeViewCell *cell= [[MyHomeViewCell alloc] init];
cell=(MyHomeViewCell*)[tableView dequeueReusableCellWithIdentifier:cellidentifier];
if(!cell)
{
NSArray *nibofMyHomeCell=[[NSBundle mainBundle]loadNibNamed:#"MyHomeViewCell" owner:self options:Nil];
cell=[nibofMyHomeCell objectAtIndex:0];
}
if(indexPath.section==0)
{
cell.MyHomeMenuLabel.text=#"Inbox";
}
}
Here ara a good tuts it could help you:
Expanding/Collapsing TableView Sections
Expandable UITableView
And this github awesome code here by Oliver Letterer.
You can create a UITableview which will contain cells on it as you said inbox, sent, setting etc.
After you need to create another UITableView which will contain your submenu buttons or labels like new,replied, deleted when click on inbox.
Simillarly you will do for rest of the cells in your main UITableView.
And don't get confuse on how will i identify which tableview will get called.
You will check for tableview name like below:
if(tableView==main)
{
///Code for main menu tableview.
}
else if(tableView==sub)
{
////Code for submenu tableview.
}
This you will do in all UITableView Delegate and Datasource methods:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
There are many ways you can do this. You could for example show each item as a section header and if the section header is tapped you show (or hide) all of the rows in that section. The rows being the 'sub menu' items (new, replied, deleted). Or you could use different sections for each part and how or hide the sections. Or show and hide rows. This is pretty much all controlled by changing the section and row counts.
I have a UITableView with some delegate methods.During load for the first time it's all ok, but during the rotation I saw that the method cellForRowAtIndexPath doesn't recall. Why?
My delegate method are:
-(NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section{
//.....
}
-(CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
//......
}
- (UITableViewCell *)tableView:(UITableView *)aTableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath{
//...This method is not called during the rotation of the device...
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
//.......
}
You need to refresh table data manually after the rotation occurs using [tableView reloadData] within shouldAutorotateToInterfaceOrientation method.
That method is only called when the cell is about to become visible on the screen and the table requests it. Once it is in the view, it will not be called again until it has scrolled out of view and then back.
You have 3 options for handling the rotation:
Use AutoLayout
Use Springs & Struts
Override layoutSubviews (which will get called on a rotation)
What you choose will depend on how complex your cell layout is. Also, make sure the table resizes on the rotation, otherwise the cells won't see a size change.
I need to have a custom cell height for all of my cells in my UITableView. In this method:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
I try this:
if ([[tableView cellForRowAtIndexPath:indexPath] reuseIdentifier] == #"imageCell")
As I have 3 different cells setup with different identifiers in my storyboard. However my app just crashes here with EXC_BAD_ACCESS.
Any idea why?
Thanks.
You're comparing a string, so you should be using isEqualToString:
if ([[[tableView cellForRowAtIndexPath:indexPath] reuseIdentifier] isEqualToString:#"imageCell"])
(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
you are supposed to calculate the height for you row, not to get the Cell of your tableView.
In my opinion, in the lifeCycle of a TableView delegate, the 1st step (before allocating each UITableViewCell), the TableView delegate call heightForRowAtIndexPath for each row (but at this moment, the UItableViewCell are not allocated). The, in a 2nd step, the TableView call
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
to create UitableView Cells.