I am trying to create a custom tabBarController, but it seems like there is a memory leak caused by presenting the different view controllers. I can see the memory usage climb when I toggle between different options. I also checked the view hierarchy and noticed that there were a bunch of UITransitionViews. My CustomTabBar is below:
import UIKit
struct CustomTabBarViewControllerObject {
let title: String
let icon: UIImage
let viewController: UIViewController
let index: Int
}
class CustomTabBar: UIView {
// MARK: - Singleton
/// if you plan on using the CustomTabBar singleton then the following should be set:
/// - viewControllerObjects
/// - presentingVC
/// - selectedIconTintColor
/// - unselectedIconTintColor
static let shared = CustomTabBar(frame: .zero)
//MARK: - Variables
private var _viewControllerObjects: [CustomTabBarViewControllerObject]?
public var viewControllerObjects: [CustomTabBarViewControllerObject]? {
get {
return self._viewControllerObjects
} set {
_viewControllerObjects = newValue
if frame.width > 0 {
updateViewControllers()
}
}
}
override func layoutSubviews() {
super.layoutSubviews()
if frame.width > 0 {
updateViewControllers()
}
}
private var viewControllerButtons: [UIButton] = []
private var displayTitles = false
private let iconSize = CGSize(width: 30, height: 30)
public var selectedIconTintColor: UIColor!
public var unselectedIconTintColor: UIColor!
public var presentingVC: UIViewController!
private var selectedIndex = 0
//MARK: - init
private init(_ presentingVC: UIViewController? = nil, frame: CGRect, displayTitles: Bool = false, selectedIconTintColor: UIColor = .text1, unselectedIconTintColor: UIColor = .text3, bgColor: UIColor = .background1) {
self.displayTitles = displayTitles
self.selectedIconTintColor = selectedIconTintColor
self.unselectedIconTintColor = unselectedIconTintColor
self.presentingVC = presentingVC
super.init(frame: frame)
backgroundColor = bgColor
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
//MARK: - Methods
private func updateViewControllers() {
guard let viewControllerObjects = viewControllerObjects else {
return
}
// remove all current icons
for view in subviews {
view.removeFromSuperview()
}
let vcCount = CGFloat(viewControllerObjects.count)
let numberOfSpaces = vcCount 1
let interIconSpacing = (frame.width-(vcCount*iconSize.width))/numberOfSpaces
//let interIconSpacing = (frame.width-(iconSize.width*(CGFloat(vcCount) 1)))/(CGFloat(vcCount) 1)
// app fails if there are too many items in view controller
if interIconSpacing < 5 {fatalError("Too many elements in viewControllerObjects")}
var lastXPosition: CGFloat = 0
let yPosition: CGFloat = frame.height/2-iconSize.height/2
var iconWidthSizeAdjustment: CGFloat = -30
// iterate through viewControllerObjects to add them to the view with icon and action
for vcObject in viewControllerObjects {
iconWidthSizeAdjustment =30
let vcButton = UIButton(frame: CGRect(origin: CGPoint(x: lastXPosition interIconSpacing iconWidthSizeAdjustment, y: yPosition), size: iconSize))
vcButton.setBackgroundImage(vcObject.icon, for: .normal)
vcButton.layoutIfNeeded()
vcButton.subviews.first?.contentMode = .scaleAspectFit
vcButton.addAction(UIAction(title: "", handler: { [unowned self] _ in
if vcObject.index != selectedIndex {
vcObject.viewController.modalPresentationStyle = .fullScreen
self.presentingVC.present(vcObject.viewController, animated: false, completion: nil)
self.presentingVC = vcObject.viewController
self.updateSelected(newSelectedIndex: vcObject.index)
}
}), for: .touchUpInside)
if vcObject.index == selectedIndex {
vcButton.tintColor = selectedIconTintColor
} else {
vcButton.tintColor = unselectedIconTintColor
}
addSubview(vcButton)
viewControllerButtons.append(vcButton)
lastXPosition = lastXPosition interIconSpacing
}
roundCorners([.topLeft, .topRight], radius: 15)
addShadow(shadowColor: UIColor.text1.cgColor, shadowOffset: CGSize(width: 0, height: -1), shadowOpacity: 0.2, shadowRadius: 4)
}
func updateSelected(newSelectedIndex: Int) {
if viewControllerButtons.indices.contains(selectedIndex) && viewControllerButtons.indices.contains(newSelectedIndex) {
viewControllerButtons[selectedIndex].tintColor = unselectedIconTintColor
viewControllerButtons[newSelectedIndex].tintColor = selectedIconTintColor
selectedIndex = newSelectedIndex
} else {
fatalError("Index does not exist: \(newSelectedIndex)")
}
}
}
This is the CustomTabBarViewController class that all tabBar items inherit from:
import UIKit
class CustomTabBarViewController: UIViewController {
public let customTabBar = CustomTabBar.shared
public let mainView = UIView(frame: .zero)
public var tabBarHeight: CGFloat = 60
override func viewDidLoad() {
super.viewDidLoad()
setUpTabBar()
}
func setUpTabBar() {
// setting up properties of customTabBar
customTabBar.selectedIconTintColor = .text1
customTabBar.unselectedIconTintColor = .text2
customTabBar.presentingVC = self
customTabBar.backgroundColor = .background1
// adding viewControllers for tabBar
customTabBar.viewControllerObjects = [
CustomTabBarViewControllerObject(title: "Home", icon: Images.home, viewController: UINavigationController(rootViewController: HomeViewController()), index: 0),
CustomTabBarViewControllerObject(title: "Search", icon: Images.search, viewController: UINavigationController(rootViewController: SearchViewController()), index: 1)
]
//adding mainView to view
view.addSubview(mainView)
mainView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
mainView.topAnchor.constraint(equalTo: view.topAnchor),
mainView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
mainView.leftAnchor.constraint(equalTo: view.leftAnchor),
mainView.rightAnchor.constraint(equalTo: view.rightAnchor),
])
// add customTabBar to view
view.addSubview(customTabBar)
customTabBar = false
NSLayoutConstraint.activate([
customTabBar.bottomAnchor.constraint(equalTo: view.bottomAnchor),
customTabBar.leftAnchor.constraint(equalTo: view.leftAnchor),
customTabBar.rightAnchor.constraint(equalTo: view.rightAnchor),
customTabBar.heightAnchor.constraint(equalToConstant: tabBarHeight),
])
}
}
CodePudding user response：
So I am going out on a limb here but in
override func layoutSubviews() {
super.layoutSubviews()
if frame.width > 0 {
updateViewControllers()
}
}
I think this is where the problem lies. This function gets called by this system fairly rapidly
private func updateViewControllers() { ...
Combine that with this line
addShadow(shadowColor: UIColor.text1.cgColor, shadowOffset: CGSize(width: 0, height: -1), shadowOpacity: 0.2, shadowRadius: 4)
And basically you have a recipe for disaster. This just keeps adding shadows. There may be other objects getting re added as well but this is what I noticed without full testing and debug. Basically shadows are fairly expensive. They use both a decent amount of computing as well as ram. This will basically re add the shadow every time. I would start by commenting the add shadow and seeing if that reduces resource usage. If it doesn't then comment out the updateViewController() in layoutSubviews().
CodePudding user response：
You can debug using instruments to see what is being allocated causing the spike. https://www.raywenderlich.com/16126261-instruments-tutorial-with-swift-getting-started