The main problem is that I tried command+drag to the view and selecting "align horizontally in the container", but for some reason(I was doing this on the iPhone 7) when I checked the other devices(such as the iPad Pro) they were not aligned. Then I tried adding constraints, which also did not work. My question is how in the world do you center a label without using Swift?
First thing first: "Center Horizontally in Container" is a constraint.
My initial guess is that you’ve neglected some sort of ambiguity or possibly created a constraint which conflicts with (and overrides) the centering constraint. If this is the case, you should see warnings telling you what the problem is.
As long as there's no vertical ambiguity, and no conflicting horizontal constraints (leading/trailing space), your label should be centered—no Swift code necessary.
I get the impression that you’re fairly new to Xcode, so if you don’t know already, you can check the existing constraints on an object in the Size Inspector, denoted by the ruler in the right sidebar. It’s quite possible that there’s an old constraint you forgot to remove, or one you added but don’t need.
Another thing to note: I’ve experienced some layout issues when switching devices in the new Interface Builder in Xcode 8—it’s just a bit buggy in my experience, especially with regard to Stack Views. If you have doubts about how something looks, I’d recommend running the app in Simulator for some devices you don’t have on hand to check it out.
Related
I'm hardly learning to implement some iOS app screens in xCode Interface Builder with auto-layout.
I've already placed some elements with working constraints but I realize it would be more practical to group them into a vertical StackView.
At first it seems pretty easy as I did it for a previous screen. However, once I embed my elements in the StackView, all my margins constraints are gone ! Also, if I try to manually put back my constraints, they don't work at all and generate ambiguity.
I don't fully understand the way iOS UI builder works, so I'd gladly need some help.
See screenshots below.
Constraints inside stack views can be quirky, but playing around with / experimenting with the characteristics can help.
In particular, adjusting Alignment, Distribution, and Spacing can often do the trick.
My question is that, can I trust on
Resolve autolayout issues’ - “Add missing constraints”
option(as in the attached Screen shot), which automatically adds constraints to the objects present in the storyboard?
I used this and tried running the app in all screen formats and it works fine, so can I continue using this or is it wrong to consider “Add missing constraints” for the constraint design. I’m new to auto layout and any kind of response, explaining this concept will be appreciated. Thanks
Utilizing the automatic constraint system is a bad idea. Most of the time, it won't work dynamically for all screen sizes. It generally adds constraints so objects appear correct in the current resolution you're designing in.
For example, it may pin a label you have placed in the center of an iPhone screen based on the distance from the left edge of the screen instead of the X value. That distance from the edge is going to stay the same when you run it on an iPad and it's going to be significantly off-center to satisfy that constraint.
However, depending on the situation, it could pin them correctly (IE leading edges to the super view instead of a constant). You can use the automatic constraint system for suggestions to reference what you need to add still, but I would not rely on it for dynamic UI.
Spend your time learning autolayout instead of throwing darts in the dark, it's really not as intimidating as it seems!
No you should not trust. Add missing constraints will add constraints that are missing. It will not add constraints that's your design actually want.
So I suggest you to understand what constraint you'll require to complete UI.
`For every control, Compiler need to know its : x,y,width and height.
For example : You drag & drop UILabel on your xib. Now you add top space constraint. So compiler will give warning. Need constraint for : X position.
On above example width and height will take according to text of label. Now you had given top space so its y position is known.
But for X you didn't give any constraint. In this case if you use Add missing constraints. compiler will add constraint for x position according to your placement. It may be your require constraint or may be not.
No iT just add the required constant so may be they are fixed so remove all constraints and try again.
Just like what the others say, "Add Missing Contraints" will always give the result of the layout that you desired. It's best that you learn to add constraints manually. But, there are times that you can be lazy for a couple of seconds by using that method but only for very simple layout.
I'll just share my thoughts about when should we use this method.
I use "Add Missing Constraints" when:
My layout is very much simple, it's like I know that when I do it automatically will yield the same result as doing it manually. This help saves a lot of time.
I am setting up constraints manually, but sometimes I don't know what constraints I am missing because the object that I am setting the constraints still shows red lines(missing constraints). This is just my purpose of learning.
I'm having a problem with Xcode constraints. I'm laying out my entire layout, then selecting all the items and having Xcode 'fill in missing constraints'. Now when I run the application in the simulator, labels and textboxes are NOT in the right places. Sometimes not visible at all (appear to be off screen)
So are there any tips or tricks? Should I layout 1 item at a time, set the constraints automatically then move to the next?
Don't trust XCode and 'fill in missing constraints' feature. The best option is to set all constraints manually. After some practice it's not that hard. You need to indicate X and Y coordinates and sometimes height/weight.
I really don't advice setting constraints automatically. It usually causes more problems than benefits.
Also check the console log at runtime. It may happen that there are conflicts between constraints and you need to fix it.
Check out the official guidlines
In the new "Xcode 6" the ability to change the center of measure of a button is missing.
In Xcode 5: http://imgur.com/jWHJp4v
Xcode 6: http://imgur.com/rsNayVZ
When I put an item (like a button or label) somewhere, I am unsure of the center, so my code that deals with the item is incorrect.
The "center" shown here in Xcode 6 is measured from the top left of the item, not the actual center.
How should I fix this so it is measured from the center like here, in Xcode 5?
You can't “fix it”. That control is gone in Xcode 6. I suspect they removed it to encourage you to use constraints instead of setting frames directly. You can use constraints to pin the center, right, or bottom of a view.
It's driving me crazy that the origin widget has been removed. It has made the placement of any object relative to another very difficult. I always use auto layout and I'm not sure how this improves it. Also, I'm not sure I follow the logic of improving a feature by making it more difficult to use. In the past, it was very helpful to set the "anchor point" of the origin and then adjust the object's position or size and have the frame grow on the unanchored sides. Now i have to break out the calculate and add position + size and then add buffer space to figure out where next object should start. And if I adjust the first object's frame in any way I need to break out the calculator again. Once you have a few objects that are relative to each other, it becomes vary painful to tweak any object's frame without having to recalculating everything.
As a side note, the removal of the ability to delete a constraint right in the size inspect is also a confusing choice. Instead we have to go through the document outline and manually delete them there. This is not a big deal for the size constraints as they are keep in the object's sub-directory however finding edge related constrains is much more difficult as they are grouped with the rest of the edge constrains and can be difficult to find. Again, is this an example of encouraging / improving auto layout? Very frustrating!
The feature has been removed from Xcode. I believe this is to account for the various sizes of devices now available, and as a result, the use of constraints is the way to go.
If you are using auto layout then this two will help you place you control in center for all the view different size of devices.
simple:
http://technet.weblineindia.com/mobile/using-auto-layout-in-xcode-6-for-universal-ios-app-development/
Advance:
http://www.youtube.com/watch?v=G53PuA_TlXk&feature=youtu.be&list=UUtc1Jt_UTPsXpAGtvlr0nUQ
Apple has removed this feature as there are 4 different size of devices only for iphone and it would be difficult to set frame for all controller and will increase the length of code and will become a tedious task as it check's the size of device and then set frame so in XCode 6.0.1 we need to use auto layout + size class and prepare our view based on the constraints set in storyboard or Xib.
Hope the above link's will help in solving your problem.
If your layout isn't too complex you can "Pin" your button or view to the top or bottom, sides, etc.
Or you can do your constraints manually here:
The first method works really well and is super easy! I had a similar problem as you looking for tools that have been left out in Xcode 6 and found this wonderful tutorial on Auto Layout:
http://www.raywenderlich.com/50317/beginning-auto-layout-tutorial-in-ios-7-part-1
If you are trying to center it I would click on the button or view you are working on and look at the size inspector here:
Look at where I circled and make sure that the bottom space and the top space are equal to the same amount (mine aren't equal), but that should give you the center.
I'm new to iOS development and I'm working through my first tutorial. One thing the tutorial kind of skipped over is positioning. I have a list where each cell has an image with some text next to it. At least in Interface Builder that's how it appears. When I actually run the app the image appears on top of the text (i.e. both have the same exact positioning from the left-hand side of the screen).
Interface Builder:
Running App:
I essentially want what, in CSS lingo, would be "float: left", or even just relative positioning with x/y coordinates for each element (i.e. if it would look the same/similar when running the app as it appears in the storyboard), that would be great.
In playing with all of various View attributes, I'm not finding anything that will position the views… I can find attributes that will position them in Interface Builder, but none of those settings seem to carry over to the app when it is running, and the image/text always appear on top of each other.
I apologize for the newbie question… it's probably something simple/obvious that has somehow slipped by me.
If you are using Xcode5 to do the test, the app will use AutoLayout feature by default. And the constraint you made for this layout seems to be wrong.If you want to position the views to the right place with AutoLayout ,you need to read some material from apple official website.If you do not have too much time to learn,you can try to edit xib without AutoLayout. You can disable AutoLayout in "file inspector" of interface builder.
If you are new to iOS development (as I am), you should familiarize yourself with AutoLayout, as suggested in Eric's answer.
If you're looking for a quick fix to the question as asked, all of the following options worked for me:
Select the label, then select the Horizontal Space Constraint and delete it.
Select the label and hit cmd-plus (i.e. cmd+shift+equals). This will delete all of the positioning constraints at once.
Turn off AutoLayout.
There are other ways to fix the problem I was having, but generally the issue was incorrect AutoLayout constraints.
If you feel comfortable in the code, I suggest manually setting the frame to a CGRect that you define with CGRectMake(origin.x, origin.y, width, height). You can also do this with the autolayout settings but I find that programmatically positioning elements gives me much more flexibility, and, as a programmer, it's much easier than trying to figure out the options in interface builder.
The iOS coordinate system is top-down, meaning that y=0 is the top of the screen and y=568 is the bottom of the screen (on iPhone 5). X is 0 on the left side of the screen.
Coordinate systems are relative to the view that they are in. In your case, your elements are in a UITableCell, which is given its own coordinate system by the rendering engine. So if you want your image to be 10px from the top and 10px from the left of the cell's edge (a la padding:10px in css), you would set its frame like so:
image.frame = CGRectMake(10, 10, 50, 50)
...assuming the image is 50x50.