Xcode is not showing all the buttons, textfields, etc. I have in my storyboard. As you can see in the image below, somehow all my elements are appearing with a "watermark" in the storyboard element inspector on the left. Why is it doing this? How can I fix it? It is driving me crazy because I cannot see where my elements are when I try and add some more...
How can I solve this and why is Xcode so buggy anyways?
You have a size class enabled (note the blue bar across the center-bottomish). My guess is that all those views are missing in that size class. Click the bar, turn it back to Any x Any.
I had a similar problem, some of my IBOutlets (labels) were showing on the Storyboard, I had no AutoLayout warnings/errors and everything seemed fine but yet some of the outlets were not showing on the Simulator.
Things got even more complicated when I noticed that SOMETIMES the outlets DID show.. strange..
I ended up wrapping the call to show the view controller in a GCD method like this (swift code):
dispatch_async(dispatch_get_main_queue()) {
[unowned self] in
let vc = self.pages[0]
self.setViewControllers([vc], direction: .Forward, animated: false, completion: nil)
}
And that solved it..
Related
I have an extremely bizarre problem. I created a UIButton and put it on my ViewController storyboard. I added a segue from the Button to another ViewController by pressing control and dragging. I also added an outlet to the corresponding ViewController file and added a border color and width (to the button). The segue and the button border work fine on the simulator but on a device the button border does not show up and the segue does not work.
The only thing I can think of that could be causing the problem is that a little while ago I accidentally deleted my Main.storyboard, so I dragged it from my trash back to my Xcode project. But I am pretty sure my app has worked on the device even after that incident. I wasn't sure if my viewDidLoad method was being fired (since that is where I set my border color and width for the button) so I added a print statement and found out that it was indeed being called. Take a look at the code below...
override func viewDidLoad() {
super.viewDidLoad()
print("Begin Setup Process...")
// Do any additional setup after loading the view.
calibrateButton.layer.borderColor = UIColor.white.cgColor
calibrateButton.layer.borderWidth = 3
}
How would I get this to work on my device as well? What I am doing wrong
Assign Your Border Styling Here...
Try adding the code to change layer properties of calibrateButton in viewDidLayoutSubviews(), i.e.
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
calibrateButton.layer.borderColor = UIColor.white.cgColor
calibrateButton.layer.borderWidth = 3
}
Also, since you're giving borderColor as white, that might not be visible if the calibrateButton is placed on a white background. Try changing it to something else that is more visible, red for example.
First try in viewDidAppear(), if it works then cut and paste it in viewDidLayoutSubviews().
I finally solved the issue. The problem was that I didn't have a height constraint on my button. I am still not exactly sure why or how this issue occurred. Why couldn I see the button text but not the border? If the segue was not working there must have been a view on top of the button that was preventing it from going off. But anyway adding a height constraint solved the problem. In answering my own question I realize that the title of my question is misleading in relation to the solution of the problem. This problem, in the end had nothing to do with wether the app was running on a simulator or the device. I just assumed it was a device issue since it was working fine on my iPhone XR simulator but not my actual iPhone 6s. However the actual problem was the screen size and how my constraints adapted to it.
I'm kind of new with ios development with swift 4, so I'm testing some functionalities.
I have a tableview inside a normal UIViewController:
The space left blank is intentionally, as I have some custom tabs.
When I show a detail from a table cell element, and then press back button, the table view gets pushed down (and up). Please see this where I show the problem.
The iphone is a SE with ios10. In simulations with iOS11, this does not happen. Developing in MacOS Sierra 10.12.6 with xCode 9.2.
Any clue on how to fix this?
EDIT:
Using the view debugger, I got this:
The selected area is a UITableWrapperView element. Behind it, is the UITableView, which preserve its constrains.
set
self.tableView.bounces = false
Or put this in viewDidAppear
let offset = CGPoint.init(x: 0, y:0)
self.tableView.setContentOffset(offset, animated: false)
It can happen because of SafeArea... Check you constraint which connects tableView top with navigation bar.
You can also try placing blank UIView between Navigation bar and tableView. Your custom tabs should be in this view. So tableView will be connected with the nearest view (which you have just added) and should not bounce.
Thats a really weird behavior. I recommend you to use the Xcode view debugger. You would be able to examine dimensions and constraints values by using size inspector.
The code where you set up your tableview, try implementing it in the method viewDidLayoutSubviews(in case you are doing it in viewDidLoad).
override func viewDidLayoutSubviews() {
//mention your tableview setup code here
}
A similar thing happened to me, and this method came quite handy. Hope this helps.
Try this for iOS 11.0
tableView.contentInsetAdjustmentBehavior = .never
I am still new to iOS and Swift and I am using Swift4 and Xcode9 to edit an iOS project which is made with a prior versions of Xcode and Swift (Xcode8 and Swift3). In the project there is a TableViewController used. So the problem is when I open the project in Xcode9 and run it, it shows some space on the top. I tried changing y values, but didn't work. My questions are,
How to solve the upper mentioned problem. (There is a question like this in Stack Overflow already. But it's not due to different Xcode version. But I even tried all the suggestions in the answers. But none of them worked for me.)
When there is a text label or something on the top of the table content, I can remove that space, from the top, but it goes to in between that label and the table added. And the label is unable to get a click action or something when it's moved to the top. How to solve that?
Any suggestion/ answer will be highly appreciated. Thank you!
You can try this
if #available(iOS 11.0, *) {
yourTableView.contentInsetAdjustmentBehavior = .never
}
Ok I'm going to attempt to answer your question but I wasn't totally positive since you didn't include any code or screenshots.
Firstly. If you mean that there seems to be a gap between where the tableView starts and where the first cell is displayed, this is correct. You can fix that by doing:
tableView.contentInset = .zero
this means that any content inside the tableView starts goes all the way to the edges.
Now for the label receiving touches. You want to look at user interaction enabled values on the storyboard:
Whenever you have views that stack on top of each other, the view UNDER will not receive touches if the view on top has user interaction enabled. If you want a touch to bleed through another view you either can
1) avoid the issue by not stacking views on top of each other (often unavoidable, like putting a label on a view and wanting the background view to do something)
2) turn off the user interaction on the view on top so the view on bottom gets the touch
tableView.setContentOffset(CGPoint.zero, animated: true)
this code will move
I am attempting to implement a "Share" feature in my iOS app with a similar look and feel to that of the Google Photos iOS app:
The bottom two rows of icons are what I care about. They look nearly identical to those displayed when using the UIActivityViewController.
In the Google Photos app, these icons appear inline with the "select photos" portion of the screen (e.g. you can still interact with the upper portion of the screen). However, the documentation for the UIActivityViewController states that "On iPhone and iPod touch, you must present [the view controller] modally."
This is the difference that is really important to me -- I'd like for the "share" icons to display inline with the rest of my content, rather than having a modal that is displayed on top of my content.
Is it possible to use the UIActivityViewController to achieve a similar effect shown in the screenshot above? If not, is there a recommended approach that I might use to implement this sort of functionality?
As discussed in another answer, reverse engineering UIActivityViewController is the only option in order to be able to achieve a similar effect. I tried this using iPhone 6s - 10.3 Simulator. The following findings may not be accurate for iOS 9.x or 11.x or above.
A. Find out all internal variables for UIActivityViewController
var variablesCount: UInt32 = 0
let variables = class_copyIvarList(UIActivityViewController.self, &variablesCount)
for i in 0..<variablesCount {
if let variable = variables?[Int(i)] {
let name = String(cString: ivar_getName(variable))
let typeEncoding = String(cString: ivar_getTypeEncoding(variable))
print("\(name)\n\(typeEncoding)\n\n")
}
}
free(variables)
The ones those got my attention at first sight are (in order) -
_activityViewController
#"UIViewController"
_contentController
#"_UIActivityViewControllerContentController"
_activityAlertController
#"UIAlertController"
On inspecting them further, I found out that _contentController is the one we should be looking for. We need to look one level deeper in hierarchy for UICollectionViewController to get to where we want to be.
if let activityContentController = activityVC.value(forKeyPath: "_contentController") as? UIViewController {
print("Found _contentController!")
for child in activityContentController.childViewControllers {
print(String(describing: child))
if child is UICollectionViewController {
print("Found UICollectionViewController!")
break
}
}
}
Why did I look for UICollectionViewController?
Debug View Hierarchy has the answer for this.
I tried adding this as a childViewController to my UIViewController -
self.addChildViewController(child)
child.didMove(toParentViewController: self)
self.view.addSubview(child.view)
child.view.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
child.view.topAnchor.constraint(equalTo: self.view.topAnchor),
child.view.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
child.view.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
child.view.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
])
IT SHOWS UP CORRECTLY ONLY IF YOU HAVE LOADED/PRESENTED UIActivityViewController FIRST.
I was able to achieve this using a silent present/dismiss call -
self.present(activityVC, animated: false, completion: {
self.dismiss(animated: false, completion: nil)
})
IS THIS APP STORE SAFE? - Most likely not.
As soon as you start stealing the view(s) or viewController(s) from UIKit's standard components, the behavior is not stable and it will break with upcoming updates for sure.
What Google Photos has is the result of way more advanced reverse engineering. In above implementation, you can't see More option screen. The hierarchy UIActivityViewController expects is broken.
Hope this helps.
Okay, I thought about this and I did some intensive research on the web but nobody ever seemed to needed to modify it like you want. So here are my guesses how Google engineers solved this:
They reverse engineered the UIActivityViewController and call some private APIs to get the same icons to show up and the reordering controllers
They use the UIViewController transitioning API and hack the view hierarchy of a modally presented UIActivityViewController, removing the cancel button and adding some custom views on top of its view
An indicator for the second option could be that the top of the presented "sheet" has a white background while the bottom has the greyish color.
Unfortunately I'm not very fit with the transitioning API as I'm just about to learn it but my understanding is that you can provide a custom object as the transitioning delegate.
This object then gets called when you present/dismiss or push/pop a UIViewController. It will get a reference to both, the presenting and the presented view controller and you can have fun with both of their views.
This should make it "quiet" easy to remove and add some subviews, change frames and colors etc while still having all the default behavior.
I hope this answer helps you to achieve what you want. However, be aware that the structure of the controller could change at any time so always make sure to also test agains betas so that you don't get caught by surprise when apple releases an update which breaks your UI. :)
Built-in Photo application fades in/out navigationBar when you tap on an image . This way Photo app allows to see it full screen.
How does it do this (fade efect)?
As I understand navigationController?.navigationBar.alpha doesn't work anymore (so you can't animate it this way).
Sharing all my finding.
Complain mode on
Frankly, I feel half pissed/like a dummy that I had to fight a good day to implement simple thing existing in Apple app.
Complain mode off
First of all here is some context. I am working with navigationBar which are provided by navigationController (vs just standalone bars which are manually dropped in your view)
There are several approaches which I found. I will mention all of them (even if I had no success using them)
1) Animate change of alpha of navigationBar
UIView.animateWithDuration(0.1, animations: {
navigationController?.navigationBar.alpha = 0
}, completion: nil)
#rmaddy mention here that it works for him. However, I believe he has a standalone bar (vs a bar managed by navigationController).
I used a tool Reveal to check UI hierarchy and found couple of things.
- There is a navigationBar which is hidden (and navigationController?.navigationBar is referencing it). So you can change alpha to your hearts joy, but these changes won't be visible.
There is however another navigationBar . I assume it's referenced in some private members of navigationController (let's call it private navigationBar). It's visible and that's what is displayed at the top of your view.
2) Use setNavigationBarHidden:animated:
This is a standard way to hide/show navigation bar. It's animated different way (it slides/up and down). However, if it's ok for you, just go with this is, because it's simple and clean.
navigationController?.setNavigationBarHidden(true, animated: true)
Additionally you can wrap it in UIView.beginAnimations, UIView.commitAnimations to animate it together with some other stuff (to make it smoother)
3) Animate change of alpha of private navigation bar.
This worked for me:
let privateNavigationBar = self.superview?.superview?.superview?.superview?.superview?.superview?.subviews[1]
UIView.animateWithDuration(0.1, animations: {
privateNavigationBar.alpha = 0
}, completion: nil)
I am going way up through the hierarchy to get a view which contains private navigationBar (which is second subview for that view).
However, this approach has multiple downsides:
I believe # of superviews? depends on your app hierarchy (vs you are using split view and so on). I think you can generalize or may be you just walk the whole hierarchy to find non hidden UINavigationBar to solve this.
I have a feeling that Apple may frown at this (your app be not accepted to AppStore)
4) Make navigationBar transparent and set background image to be transparent and change alpha channel on it.
I can't find where I read about this idea. There was couple of mentioning.
There is Apple example app which shows how to customize NavigationBar, including making it transparent.
It's interesting that this example app works for me (the navigation bar is transparent in it). However, when I tried this code in my app it didn't work (I still didn't figured out what is going on with this). As usual there are bunch of variables (may be something in Info.plist, also they subclass NavigationController, also may be something in view hierarchy)
5) Adding standalone navigationBar
You can hide a bar provided by navigationController. Add your own to the UIView, wire it to #IBOutlet and use alpha animation on it (most likely that's what #rmaddy was referring too).
I checked and this is work.
This approach is used in this tutorial.
However, it has a downside:
I believe it won't handle well rotation, increase of statusbar height while call or GPS
Each time when I see a code like this (written in the article) I know that there will be problems with resizing: CGRectMake(0, 0, CGRectGetWidth(self.view.bounds), 64.0)
You can potentially replace it with constrains. I went this route, but stumble upon some issues.
6) Other methods
I saw two more methods. I don't know whether they will work or what will be downsides:
One of them in this question: How to hide/show status bar and navigation bar by fading in/out at the same time like the Photos app in iOS 7?
And this answer: https://stackoverflow.com/a/18063898/422080