The result today is:
As you can see there is an error with the view which contains both Labels doesn't respect the constraint between icon and its.
Global constraints:
Did you see some configuration errors guys on constraints?
Aren't you getting constraint issue in your "Xib" or "Storyboard" because when I added the same constraints that you have used, I am getting constraint conflict issue.
After correcting it, It is like this now:
First the Texts layout.centerX = centreX is not required if you are adding leading and trailing.
Second Icon View.leading = leading + 16 if you want the icon view to stick to the left side.
Related
I have two columns of text. The left is anchored top, left and bottom and the righthand side conversely. This still generates leading and trailing warnings. How do I connect the two columns' rows to tell Auto Layout to just expand the space in between?
While YOU know exactly what text you're going to put into those labels, Storyboard / Interface Builder (IB) has no idea.
So this looks great to you:
But... what happens if the "Date" text changes to "When do you want to get started?":
Because we haven't given a constraint between the two labels, they overlap.
So, let's do the same thing on both "rows" but, add a Trailing-to-Leading constraint of 8 between the labels:
We've prevented the overlap but now we see a new problem (that IB will warn you about)... Which label should get compressed? IB (and auto-layout at run-time) will make its own decision, which may not be what you want, and which may be inconsistent between similar layouts.
To fix that, we give a higher Content Compression Resistance Priority to the label we do not want compressed:
And here is the result - top "row" has the left-hand label at the default of 750, and the right-hand label at 751, and the bottom "row" has the left-hand label at 751, and the right-hand label at the default of 750:
It looks the same as "C" but we no longer have errors/warnings from IB.
So, even if you know the text in your two columns will never be enough to overlap, IB is going to encourage you to provide enough constraints (and priority settings) to make sure you get exactly what you want.
I'd like to perform an interactive gesture-based animation with my views that requires moving a view which is centered in the screen to the top-left corner of the screen. I can't seem to interpolate between the position of two different x/y constraints (only changing the constant), so as an alternative, I thought perhaps I could lay out the views in my storyboard, then animate them by changing the frame directly. Is there a good way to do this, or is it a bad idea?
You don't need to remove them! Just deactivate them is enough.
If you have seen the docs, you should know that the constraints property of a UIView returns the constraints that it has as a [NSLayoutConstraint]. You just need to loop through this array and deactivate all the constraints!
for constraint in someView.constraints {
constraint.active = false
}
Or using forEach:
someView.constraints.forEach { $0.active = false }
The advantage of deactivating constraints instead of removing them is that you can activate them again easily when you need it.
If I were you I would choose to animate constraint instead. Even if you cannot change the constraint constant for some reason, you can still remove the previous contraint and add a new one.
To do so you'll need to :
Keep a reference to the constraint you want to change
remove it from the view
set the new constraint and add it to the view
keep the reference of that new constraint
Animate with :
UIView.animateWithDuration(0.5) {
self.view.layoutIfNeeded()
}
The app allows users to post images/follow others etc.
So it works fine but i get the following warnings:
(I know some has to do with AutoLayout constraints but how do i know which is causing the problems?)
2015-07-05 17:19:37.701 Pixym[1271:72192] CUICatalog: Invalid asset name supplied:
2015-07-05 17:19:37.702 Pixym[1271:72192] Could not load the "" image referenced from a nib in the bundle with identifier "HP.Pixym"
2015-07-05 17:19:37.705 Pixym[1271:72192] 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.
(Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
(NSLayoutConstraint:0x7fa83b822a40 H:[UIImageView:0x7fa83b8529a0(300)],
NSLayoutConstraint:0x7fa83b85ccb0 H:[UIImageView:0x7fa83b8529a0]-(10)-| (Names: '|':UITableViewCellContentView:0x7fa83b871ff0 ),
NSLayoutConstraint:0x7fa83b8643d0 H:|-(10)-[UIImageView:0x7fa83b8529a0] (Names: '|':UITableViewCellContentView:0x7fa83b871ff0 ),
NSLayoutConstraint:0x7fa83b80ab00 'UIView-Encapsulated-Layout-Width' H:[UITableViewCellContentView:0x7fa83b871ff0(375)])
Will attempt to recover by breaking constraint
NSLayoutConstraint:0x7fa83b822a40 H:[UIImageView:0x7fa83b8529a0(300)]
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.
Any help will be appreciated.
From the constraints, it seems you have an imageView with a width of 300 and a left and right padding of 10. That would work fine on iPhone 5(where the screen width is 320) but it will crash on iPhone 6/ 6 Plus because there the width is bigger.
What you need to do, is figure out how would you want the image to look like on all screens. Is the 10 pixels padding more important than the width or you would like it to always have a width of 300?
If you want the width, remove the other 2 constraints and add a center horizontal in container constraint for the image.
In the other case, just remove the width constraints and all should work.
Good luck!
I have been trying to insert a UIButton programatically, as I am using Autolayout I have done something like that...
[self.add_scroll_view addConstraints : [NSLayoutConstraint constraintsWithVisualFormat : #"V:[date_picker_btn]-[button(==date_picker_btn)]"
options:0
metrics:nil
views:NSDictionaryOfVariableBindings(date_picker_btn, button)]];
I have two questions here...
i) Button inserted is not the same width as date_picker_btn even though I mentioned button(==date_picker_btn).
ii) I have inserted properely, however below views should align accordingly down to accommodate new button... How to do that...
Thanx
When using the visual format language, the superview of the view for which the constraint is being described is represented by the | character.
Example:
V:|-20-[mybutton1(>=70#500)]-[mybutton2(==mybutton1)]-30-[mybutton3]-|
Refer this link
For first question I have mentioned V: so it means (==) will assign height not width. To set width it should start with H:.
Next question, To insert a button between two existing button need to handle already existing constraints, here above I have added new constraints only not handle old existing, so I have to delete the existing constraints, so that it avoid conflicts. Works fine.. Happy coding :)
I have a scence with a bunch of labels and buttons. When you tap on a button a view slides up from the bottom with controls in it, a kind of keyboard so to say. It "looks" like this:
-----------------------------
| |
| [Button 1] [ Slider 1 ] |
| |
| [Button 2] [ Slider 2 ] |
| |
-----------------------------
This "keyboard" is created at the very beginning when the view loads and the animation is done switching its heigth from 0 to its instrinsic content size. This escene only supports landscape mode and it took me quite a while to keep the "keyboard" on the view when the device rotates 180 degrees.
The problem I see pops up with either of the two following situations:
The device rotates 180 degrees.
The "keyboard" is called.
This problem as follows:
Unable to simultaneously satisfy constraints...
.
.
.
.
(
"<NSLayoutConstraint:0x718c6c0 UIButton:0x717e0d0.centerY == UISlider:0x717d9d0.centerY>",
"<NSLayoutConstraint:0x7190a00 UIButton:0x717e0d0.centerY == UISlider:0x717d9d0.centerY>"
)
The error log gives me this error twice, once for each set of button-slider.
What I think is weird is that the conflicting constraints are exactly the same. I thought I did some copy-paste mistake and added the same constraint twice, but it's not the case.
I'm guessing it has something to do with updateViewConstraints being called upon rotation and also whe I perform the animation, but I cannot see why only these constraints are affected since there are some more in this "keyboard" view.
All and all, this Autolayout is beign quite more difficult than Apples whants to claim. In my opinion, of course.
Any ideas?
EDIT: the constrains are set all in code using mainly the visual language format. The constrains of the controls inside the "keyboard" are added into the "keyboard" view which is the normal thing to do, I believe.
Just to try it out, I changed the problematic constraints and, instead to adding them to the "keyboard" subview, I added them to the self.view ("keyboard" superview). All the sudden, no more errors are shown.
Despite of that, I'd really like some discussion on the matter because I still don't know what's wrong and I just had a lucky shot. I'd really like to undestand it.
The fact that the conflicting constraints are exactly the same is in fact the error. With Auto Layout, you can't have a constraint twice. That will generate the error you see above.
Definitely, you have added the constraint twice. You can see this from the memory addresses. You have two different NSLayoutConstraint instances, 0x718c6c0 and 0x7190a00. However, the instances each refers to are both the same. That being that the vertical center centerY of your UIButton instance 0x717e0d0 should be in the middle of the UISlider 0x717d9d0.
Possibly your updateConstraints method has been called and you haven't checked to see if a constraint already exists before adding it again.
I don't know if this may help you but I just used this tutorial for setting up constraints to buttons and labels in my app