I have a custom UITableViewCell which has a thumbnail and bunch of text. The row height is configured to be calculated automatically using
tableView.estimatedRowHeight = 129;
tableView.rowHeight = UITableViewAutomaticDimension
The row height should be calculated as exactly 138 points.
Everything looks great on the iPhone 5. However, on iPhone 6 Plus, the auto row height fails INTERMITTENTLY for random rows with the following log.
(
"<NSLayoutConstraint:0x17009ddd0 V:|-(20)-[scoop.ThumbnailImage:0x124d2a5a0] (Names: '|':UITableViewCellContentView:0x124e23200 )>",
"<NSLayoutConstraint:0x17009de70 UITableViewCellContentView:0x124e23200.bottomMargin == scoop.ThumbnailImage:0x124d2a5a0.bottom + 20>",
"<NSLayoutConstraint:0x17009e780 V:[scoop.ThumbnailImage:0x124d2a5a0(90)]>",
"<NSLayoutConstraint:0x17009ef00 'UIView-Encapsulated-Layout-Height' V:[UITableViewCellContentView:0x124e23200(138.333)]>"
)
The last line of the log seems to say that for some reason the row height was calculated as 138.333 instead of 138. I have been banging my head for a while now but I am unable to figure out why this is happening. Can some one please help?
Update: This is how my table view cell looks like.
UPDATE I couldn't get the code out of the main repo since its a part of a bigger project. But I have managed to reproduce the issue with a very simple sane project. Please find it here on github.
This warning is telling you there's a conflict in your constraints.
Reduce the priority of the height constraint to 999 and it will go away. Tested it in your Github project and worked perfectly.
0.333 on a 3x scale display (which iPhone 6+ is) is probably connected with the cell separator.
Note that your constraints don't set up the size of the cell, they set up the size of the contentView. But the cell has to add 2 pixels (= 0.666 points) to the cell height for the cell separator. Autolayout tries to keep view positions on integer boundaries so adding 0.666points to the cell height can result in adding 0.333 to your content height.
You can avoid the error by setting your table separators to None. Although setting up one of the priorities to 999 (usually the bottom priority) as the other answer has suggested is a good solution in general.
The warning is telling you exactly what the problem is, but you may not realize it. The first three constraints are for a 90 pixel-high image that's 20 pixels below the top of its container, and 20 pixels above its container's bottom margin. That's 130, and that's not compatible with the fourth constraint, which wants a total height of 138. However, because the bottom edge constraint is relative to the container's margin, that adds a certain number of pixels more. Either remove the total height constraint (my recommendation), or change the top and bottom edge amounts.
Related
I have a custom xib file and am trying to load a picture when the table view is launched. However I get this error of multiple constraints. I have set the row height of the tableviewcell automatic, and the sum of three views that comprise the xib view add up to 408 pixels. I have also tried setting the row height to 409 given the error said 408.333 pixels for the cell, however this did not help.
This is a common issue, particularly when using UIStackViews in table view cells.
The problem is that as auto-layout is "doing its thing," it has to make several passes to calculate the complete layout.
When it encounters a stack view in a (non-fixed-height) cell, it needs to deal with the various heights of the stackView's arranged subviews, the table width and height, and the cell height. In addition, because a point on a #2x scale device uses 2 pixels, and on a #3x scale device it uses 3 pixels, auto-layout has to manipulate heights around one-half-points and one-third-points, respectively.
I think I would say it's not surprising that at some point during those calculations auto-layout prints error / warning messages to the console.
Setting the Priority on the stack view's Bottom constraint to 999 allows auto-layout to, I guess, temporarily break the constraint without coughing up the warning.
So... is it a Bug? Or is it Unavoidable? Only Apple knows for sure. :)
I have a custom UITableViewCell which has a thumbnail and bunch of text. The row height is configured to be calculated automatically using
tableView.estimatedRowHeight = 129;
tableView.rowHeight = UITableViewAutomaticDimension
The row height should be calculated as exactly 138 points.
Everything looks great on the iPhone 5. However, on iPhone 6 Plus, the auto row height fails INTERMITTENTLY for random rows with the following log.
(
"<NSLayoutConstraint:0x17009ddd0 V:|-(20)-[scoop.ThumbnailImage:0x124d2a5a0] (Names: '|':UITableViewCellContentView:0x124e23200 )>",
"<NSLayoutConstraint:0x17009de70 UITableViewCellContentView:0x124e23200.bottomMargin == scoop.ThumbnailImage:0x124d2a5a0.bottom + 20>",
"<NSLayoutConstraint:0x17009e780 V:[scoop.ThumbnailImage:0x124d2a5a0(90)]>",
"<NSLayoutConstraint:0x17009ef00 'UIView-Encapsulated-Layout-Height' V:[UITableViewCellContentView:0x124e23200(138.333)]>"
)
The last line of the log seems to say that for some reason the row height was calculated as 138.333 instead of 138. I have been banging my head for a while now but I am unable to figure out why this is happening. Can some one please help?
Update: This is how my table view cell looks like.
UPDATE I couldn't get the code out of the main repo since its a part of a bigger project. But I have managed to reproduce the issue with a very simple sane project. Please find it here on github.
This warning is telling you there's a conflict in your constraints.
Reduce the priority of the height constraint to 999 and it will go away. Tested it in your Github project and worked perfectly.
0.333 on a 3x scale display (which iPhone 6+ is) is probably connected with the cell separator.
Note that your constraints don't set up the size of the cell, they set up the size of the contentView. But the cell has to add 2 pixels (= 0.666 points) to the cell height for the cell separator. Autolayout tries to keep view positions on integer boundaries so adding 0.666points to the cell height can result in adding 0.333 to your content height.
You can avoid the error by setting your table separators to None. Although setting up one of the priorities to 999 (usually the bottom priority) as the other answer has suggested is a good solution in general.
The warning is telling you exactly what the problem is, but you may not realize it. The first three constraints are for a 90 pixel-high image that's 20 pixels below the top of its container, and 20 pixels above its container's bottom margin. That's 130, and that's not compatible with the fourth constraint, which wants a total height of 138. However, because the bottom edge constraint is relative to the container's margin, that adds a certain number of pixels more. Either remove the total height constraint (my recommendation), or change the top and bottom edge amounts.
I'm trying to place a UITableViewCell containing a single UIImageView in a UITableView using dynamic cell heights with AutoLayout (i.e. tableView.rowHeight = UITableViewAutomaticDimension).
The images I will be displaying have a specific ratio (1000:667), but there are other cells besides the image cells. I've built my constraint logic for this cell to respect the Aspect Ratio of the UIImageView.
Therefore, to avoid malformation or parts of the image not being shown (clip subviews) the aspect ratio constraint should determine the cell's height depending on the device screen width.
The cell was built in a Nib file with the following constraints:
Apparently this works, since the cell's height is set accordingly on runtime depending on the device (simulator) used.
The problem is I get lots of breaking constraint error logs (below). Any ideas why iOS/the table view complaints about this constraints?
Suggestions on different approaches to displaying a UITableViewCell that respects the aspect ratio would be appreciated too.
Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x7ff5097a7910 UIImageView:0x7ff5097393a0.width == 1.49925*UIImageView:0x7ff5097393a0.height>",
"<NSLayoutConstraint:0x7ff509739550 V:|-(0)-[UIImageView:0x7ff5097393a0] (Names: '|':UITableViewCellContentView:0x7ff5097a8e10 )>",
"<NSLayoutConstraint:0x7ff5097aa180 UIImageView:0x7ff5097393a0.centerY == UITableViewCellContentView:0x7ff5097a8e10.centerY>",
"<NSLayoutConstraint:0x7ff5097a8c70 H:|-(0)-[UIImageView:0x7ff5097393a0] (Names: '|':UITableViewCellContentView:0x7ff5097a8e10 )>",
"<NSLayoutConstraint:0x7ff5097a8cc0 H:[UIImageView:0x7ff5097393a0]-(0)-| (Names: '|':UITableViewCellContentView:0x7ff5097a8e10 )>",
"<NSLayoutConstraint:0x7ff5097b6440 'UIView-Encapsulated-Layout-Height' V:[UITableViewCellContentView:0x7ff5097a8e10(276)]>",
"<NSLayoutConstraint:0x7ff5097b4930 'UIView-Encapsulated-Layout-Width' H:[UITableViewCellContentView:0x7ff5097a8e10(414)]>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x7ff5097a7910 UIImageView:0x7ff5097393a0.width == 1.49925*UIImageView:0x7ff5097393a0.height>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
This one cause b'cos u gave unnecessary autolayouts (height, width and center y) conflits.
eg. you gave height then top and bottom, height is fixed still you gave top and bottom alignment... that's unnecessary...
you can try this suggestions.
1)center y + Trailing + Leading + Height.
2)Top + Bottom + Trailing + Leading.
3)height + width + center y + Leading
and many more
I hope you understand...
Fdo, the logs that you have posted clearly explains what is going wrong in there :)
What is the issue?
You have aspect ratio being set on imageView. As a result imageView will try to resize itself on assigning the image, while maintaining the aspect ratio that you have specified. So ImageView's height and width can/may vary depending on the image that you are assigning.
You have applied trailing and leading space constraint from imageView to the cell's contentView. That means no matter what happens you want the image view to cover the entire width of the cell. You are conflicting with your own constraint. Just above you said imageView is free to change its frame now you are saying it should cover whole width of cell how is that even possible buddy?
Similarly, you applied top and bottom constraint on image view to the cell's contentView. Now why is that not breaking then? Simple because cells height is dynamically being calculated based on the image you pass to imageView. So obviously the imageView's size after resizing will be equal to the height of cell. So no issue with cell height.
How to solve ?
Simple remove trailing and leading space constraint on imageView to cell's contentView and instead apply horizontally centre constraint on imageView that will give imageViews x position as well and will not mess with the width of imageView. Hence no constraints breaks and everything will work like charm
Extra piece of advice
When you have specified that imageView will have top and bottom constraint to cells content view which means that imageView height will always be equal to the cell's height, dude does it seriously make any sense to say that imageView will be at vertically centre of cell? Because anyway your imageView will cover the whole cell top to bottom.Any way it won't break anything but passing constraints more than what is actually needed is not the best thing to do as it might result in other consequences in future.
Hope it helps.
For autolayouting any view, only thing required to be satisfied is all views should get width, height,and x and y positions.
Now from your question, it looks that out of 6 constraints that you provided, only last 4 constaints are self sufficient to complete the requirements, so first 2 constraints are not required. Just remove them. All things will be fine.
The warning messages you are seeing is due to more than 2 constraints that you provided confuses system to take which out of them.
I have a label in a tableview cell with several constraints in Interface builder.
The cell is self sizing and thats working fine.
My problem is, that the "trailing space" constraint is not working.
The text is not broken and goes to far to the right - out of the screen.
I dont understand this. If someone could help me out, what be fantastic, because I am now searching for hours and dont find the root cause.
The Label is set to 0 lines by:
cell.commentLabel?.numberOfLines = 0
http://picpaste.com/p1-AmKNGkwx.jpg
http://picpaste.com/p2-7ODUyyoc.jpg
The problem is that you're setting a fixed size (600 x 444 - based on your comments above) on your tableview, which is larger than the logical resolution of the width for most devices and this causes the cells to expand beyond the visible area.
So, you must remove the fixed constraints and add some relative ones (for example match the width of the superview & set the bottom of the tableview to the top of your 'footer' - or whatever makes sense in your case... you can even stick with the hardcoded 444 for its height - the width is the important one here)
I'm currently trying to figure out what I am doing wrong with the following constraint-based UITableViewCell layout (iOS 8).
My cell is laid out as shown in this image:
There is an image view on the left, a label on the right, and both should be touching the cell margins everywhere. The image has a fixed size (64x64), the label's height will always be smaller than that. I want the image's height to cause the cell to expand the height to the correct value (image height + 2 * margin).
The problem is this: I have three constraints for the vertical size, V[Image(64)], Reset.bottom == UITableViewCellContentView.bottomMargin and Reset.top == UITableViewCellContentView.topMargin (all defined via the storyboard). When I display the cell, I get an unsatisfiable constraints error. The UIView-Encapsulated-Layout-Height constraint interferes with my constraints, and auto layout breaks my image view height constraint. Everything looks as it should, but I don't like errors at runtime.
If I give my height constraint the priority 999, everything looks fine, no errors.
So my understanding is, that my height constraint will be broken in both cases at runtime.
But when I delete the height constraint altogether, the image displays at its original height (the file has different resolution than what I display in the cell). Why is this, or what am I getting wrong here?
Edit/Update: I just noticed I was wrong about everything working. The initial display of my cell is fine, but when the cell changes (in my case I am moving another, simple single line label, cell below it) my cell changes its height to the default row height (44 pts), squashing the image in the process. This happens in both cases, when auto layout breaks my constraints or when I reduce the priority of height to 999. I'm really at a loss as to how to get these cells to do what I want.
You should try setting the estimatedRowHeight property in code, and also, depending on which version of iOS 6 you're using, set the rowHeight property to UITableViewAutomaticDimension,
self.tableView.estimatedRowHeight = 44;
self.tableView.rowHeight = UITableViewAutomaticDimension;
The default rowHeight for nib or storyboard table views, is supposed to be changed to UITableViewAutomaticDimension at some point; I don't know if it has yet in 6.0.1, so that last line may or may not be necessary.
Are you supporting older version of iOS? If that is the case, be sure to uncheck the Relative to margin option for the constraints that are complaining.