I am adding a textfield to each row in tableview and releasing it after adding it to the cell.
I want to reuse when UIButton is clicked.
I tried some methods but it does n't worked.
Help me how to reuse it.
Try to do an custom cell view. Subclass the UITableViewCell and use the normal reuse of cells, that is the best way to do it. Improves scrolls on slow devices like iPhone 3G.
Take a look here.
Related
I have this kind of problem where I want to download some images that will be used as thumbnails for each cell.
In order to achieve this behavior, there is a thread working in each UITableViewCell that have the role of downloading and saving the image.
But I want to stop the thread from working if the cell is not visible anymore.
Is there some delegate methods for UITableViewCell like viewWillDisappear that will help me solve this issue?
If I am thinking wrong, Is there any other way that will help me achieve this same behavior?
Thank you for your help.
UITableViewCell is only for rendering something to the screen. The controller that is controlling your tableview should be the one downloading the thumbnails and reload its data once it has the thumbnails.
A tableview only has 1 cell, it copies it in order to display the multiple rows.
Use the delegate method "willDisplayCell" to set the data of your custom tableview cell.
Due the reusable cell mechanism a single instante of UITableViewCell can be reused for display different data so UITableViewCell is not meant to be used for this logic but only for presentation purpose.
I suggest you to rethink your app logic
When attempting to create a form with UITextFields, it appears that cellForRowAtIndexPath: gets called every time a user scrolls up and down the tableView. When this happens, a new UITextField is created, and the old UITextFields are no longer visible. Is there a way for the cellForRowAtIndexPath: method to be called for just one iteration?
Check the docs for UITableViewCell, especially A Closer Look at Table-View Cells and the section about static cell content.
Perhaps you might consider a simple UIScrollView rather than a UITableView? It's difficult to tell what you're trying to accomplish here. Perhaps add a bit more detail to your question.
Create UITableViewCell nibs in Interface Builder with UITextFields and link all of the objects with the viewController class.
I have a TableView with one cell and I want to insert in this cell a lot of text so I think I'll need to use a ScrollView for scroll the text.
How can I insert? Is correct this method?
This is a help in the application, is correct use this modality?
Sorry but I'm a beginner and I don't have an iPhone or iPod, thanks!
While I concur with 7KV7's original comment, it doesn't look like there is need of a tableview in this scenario...
Just in case someone else happens upon this looking for an answer to the "Scrollview in a Tableview" question here are few clarifying points for the above comments.
The technical problem with having a tableview and a scrollview together on the same view is that UITableView is already a descendent of UIScrollView and if you attempt to handle both in the same view then you will end up with quite a mess with conflicting delegate messages.
As suggested by iPhonePgr, you can create a custom UITableViewCell. The first thought would be to let the UITableViewCell act as the delegate for it's own scroll view. The problem here is that the cell and it's contents could be discarded or reused at any moment as part of tableview's dequeue functionality.
So some ground rules to guide your implementation:
Whatever your solution, you're probably going to end up making a custom controller class, possibly derived from NSObject and implementing UIScrollViewDelegate.
The custom controller object acts as the mediator between the model object and the cell.
You will probably have an array or array-of-arrays that mirrors the model hierarchy driving the UITableView structure.
Because the cells can be discarded at any time you will have restore the scroll view state on cell initialization and preserve the state has part of handling your delegate actions or through a custom UITableViewCell implementing prepareForReuse.
Hopefully these points will come in useful to anyone who runs across this entry.
You need to create a custom cell by inheriting UITableViewCell and then add UIScrollView in the customcell. Then Use that cell in the Table view.
you can put your text in UITextView and add it as a subview in your UITableViewCell,because
UITextView is inherited from UIScrollView,
No need to add UIScrollView if you use UITextView
When you create UITableView you implement a number of delegate method which you can see by pressing the window key and then double clicking the UITableView delegate . In one of the methods you can set the cell height as per your requirement. By doing this your cell height can vary.
- (CGFloat)tableView:(UITableView *)resultTableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 150;
}
As your table has a defined height, when the text in cell will be too much to contain into a scrollview will be automatically inserted.
I've got an array of buttons in a UITableViewCell.
I populated them all through the cellForRowAtIndexPath method, but my tableview gets sluggish even though I have released everything.
Should I be using a custom UITableViewCell to populate?
Any suggestions on how to make this as smooth as possible for the user would be great.
Screenshot below.
You could create a custom cell / custom view pair for this specific cell, where you can draw all yours buttons in drawRect:. However, this would essentially draw all your buttons as an image so you wouldn't be able to tap them, but I guess you can always create a UITapGestureRecognizer to your cell (you'd still have to figure out which button was pressed by examining x,y values).
Still, I don't see any point in adding your tag buttons inside a UITableViewCell. You could come up for an alternate design in your UI, i.e. a UIView presented on top of the table, or a modal controller maybe.
I have a UIScrollView that I am using to simulate a UITableView like interaction because rows are a bit more complex than what UITableView has to offer. I have 4 UILables a UIImageView and a UIButton for every row. The end result is a lot of subviews.
Even with only 10 rows,the scroll view that looks fine in the simulator but has a fairly low frame rate on the iPhone 4. This is a resource consumption issue for sure.
Is there a way to optimize the redraw durring scrolling like double buffering?
If not is there another way to get customizable UITableview functionality?
thanks
Does every View have 4xUILabels, a UIImageView and a UIButton?
I would create a nib file with a custom UITableViewCell (You can make those as complex as you want), then you can reuse the cells to help with your performance.
Information on how to do this is here:
http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/TableView_iPhone/TableViewCells/TableViewCells.html#//apple_ref/doc/uid/TP40007451-CH7-SW1
I think you probably want to create a custom subclass of a UITableViewCell as the UITableView will handle all the redrawing for you. In a custom UITableViewCell you can add as many subviews as you like.
Take a look at http://cocoawithlove.com/2009/04/easy-custom-uitableview-drawing.html.
UITableViews are subclasses of UIScrollView (or at least conform to their behavior), but you really want to let the iPhone handle the selective drawing/cell reuse for you that the UITableView provides.
You should use UITableView if it does everything you need.
However if your tableview cells are really complicated, or you want to enable paging on the scrollview, you should take a look at the PageContol sample code that Apple provides. In a nutshell, you watch for movement in scrollViewDidScroll: and load new "pages" just before they become visible. This method works very well in practice for arbitrarily long lists of pages.