This problem is driving me nuts.
I have a prototype UITableViewCell in my storyboard. It contains a bunch of subviews. One of the subviews, a UILabel, is misbehaving.
When the tableview loads and is displayed for the first time, all of the cells look fine. However, as the tableview scrolls down, eventually one of the cells shows up without the UILabel subview. It seems that it is always the first cell that is being recycled.
If I continue scrolling down the tableview, however, as soon as the misbehaving cell is clipped by the top of the tableview (when it begins to be scrolled off the top of the screen), the label appears just as it should.
So it seems that the label is there, and it receives the string that I assign to it in my cellForRowAtIndexPath method. It's just not getting drawn for some reason. I've tried inserting setNeedsDisplay messages in various places, but that hasn't helped.
What is also strange is that I'm using the very same UITableViewCell subclass with a duplicate view hierarchy in the storyboard in a different view controller, and there I don't have any trouble.
Anybody have some idea of how I can start to unravel this mystery?
Thanks!
It sounds like it's only a problem when you use a reusable cell, which means that the values on reusable cells may not be getting set until you're ready to scroll off.
Related
I am making a to do list app and have 3 custom cell types. For task cells, it is just an imageview on the left and a textview on the right. I would like the cell to automatically resize itself when the textview text is to large for a single line.
I have added the correct constraints and have added this to viewWillAppear
tableView.estimatedRowHeight = 30
tableView.rowHeight = UITableView.automaticDimension
However, when going into the view with the tableview, the cells remain small for a second and then expand to their correct size. Also, when initially adding the task, the cell doesn't resize unless either going back and opening the view controller again or the tableview is scrolled up until the cell is out of view and then letting go.
This is very odd behaviour and even happens when removing the two lines above from viewWillAppear. It just happens for no reason.
I would like the cells to be of the right size when going into the view and not resizing a second later.
An example of what this looks like is below
Okay so I finally found the answer. I made my cell programmatically with auto layout and some of that was setup in the layoutSubviews() method inside the cell. This method is only called when needed. So when scrolling up or down.
To fix this, in your cellForRowAt method, just call
cell.layoutSubviews()
I have a custom UITableViewCell completely written in code (no IB), it has an accessory button that simply calls didSelectRowAtIndexPath on the table view, and it works correctly and the method is called without problems.
However, when I tap on the cell itself (not on the accessory view) nothing being called, why ?
EDIT: the code is huge to put here ... however, the custom cell contains a ton of labels, couple images and scroll view ...
This is a shot in the dark, but if each cell has many different objects on it (i.e. images, labels, etc) then it may not be working because those objects are what the user is hitting when they try to click a cell. Does the cell turn blue (indicate selection) at all? If not, try hiding/removing those objects for now and see if it works.
If that is the case, then what you may want to do is create an invisible cell or button that sits on top of the other objects and calls didSelectRowAtIndexPath from behind the scenes.
This should solve your problem:
Raise selection event (didSelectRowAtIndexPath) when subview of UITableViewCell is tapped
Try setting your view's userInteractionEnabled property to NO.
This will make it ignore all touch events, and then the views under it will be able to catch these events. - Felipe Sabino
I'd partially answer my question: the wide scroll view is preventing the cell from calling didSelectRowAtIndexPath, removing the scrollView will solve the problem, however, I want to call this method with the existence of the scrollView ... anyone got ideas would be highly appreciated ...
You must post your code to understand what have you done...You have to check out this example to understand whether your code is correct or not...
http://www.edumobile.org/iphone/iphone-programming-tutorials/impliment-a-custom-accessory-view-for-your-uitableview-in-iphone/
I have a tableview with imageviews and textviews in each cell. When my view is loaded one of the textviews is invisible. But when I start scrolling the textview appears, so that my view looks as it is supposed to look. Does anyone know why this is happening?
P.S. I have read about reusing cells when scrolling so I have been very careful to construct my cells correctly.
Without code, no one can give you a exact answer. But for a guess....
Is your data is getting populated after your table call cellForRowAtIndexPath? When the cell populates the first time, no data, so the cell is in it's unformatted state. By the time you can interact with the table and scroll it off and on screen (which calls cellForRowAtIndexPath again), the data has been populated and so the cell looks as expected.
You can test this by putting a breakpoint in your cellForRowAtIndexPath method and check to see if your data objects are initialized or still set to nil.
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 UITableView and I am having an issue with whenever I try to click on the Cell. When the cell is highlighted it puts some test on top of the text that is already on the cell make the text on the cell hard to read. This only happens while I have the cell highlighted.
Please help me with this issue.
Thanks
I had a similar problem and then realised that I wasn't using the cell dequeuing thing properly and what had happened is that every time the cell is reused a new UIlabel was added and the text from the datasource set to that, but the UILabels from the previous time the cell was showing were still there. But you only see them when the cell is highlighted because when it's not highlighted the background is not clear, but when the cell is highlighted then the UIlabels become clear and you see the other UIlabels that are behind it.
It's quite serious as everytime cell's are dequeued (ie everytime you scroll on the tableview) all of the subviews you've added a duplicated. And it increases memory usage severely.
To fix I used the code from the apple docs on customizing table cells. You have to use tags to retrieve the subviews if the cell is dequeued.:
http://developer.apple.com/iphone/library/documentation/userexperience/conceptual/TableView_iPhone/TableViewCells/TableViewCells.html#//apple_ref/doc/uid/TP40007451-CH7-SW15