How to remove all subviews of a view in Swift?

In Swift, you can remove subviews of a view by using a loop to iterate through each subview. Swift provides a method called removeFromSuperview() to remove a view from its superview. In this article, you will learn how to use this method with some examples.

removeFromSuperview()

This method belongs to the UIView class in Swift. This can be used to remove a view object from its superview. To call this method, you need to call it from a view object which needs to be removed from the superview.

When you run removeFromSuperview() on a view, it sends a message to its parent view requesting that the view be removed from its subviews array. This indicates the view is no longer kept by its parent view and can be deallocated if no other strong references to it exist. The view's window attribute is also set to nil to signal that it is no longer visible on the screen.

Syntax 

Here's the syntax of how to use removeFromSuperview()

// create a view object
let subView = UIView()

// add it to the parent view
parentView.addSubview(subView)
// ...some other code…

// remove this subView from the parent view
subView.removeFromSuperview()

In this example, an UIView instance called subView is created and then added as a subview of parentView using the addSubview() method. After that, removeFromSuperview() is called on subView to remove it from parentView. After this line of code executes, the subView will no longer be displayed on the screen. It is no longer a subView of the parentView.

Here's a More Detailed Example with Additional Context

• Step 1 − Create a ViewController to test this method

• Step 2 − Create some UIView properties

• Step 3 − Configuring the redView and adding it to the superView along with some constraints

• Step 4 − Configuring the yellowView and adding it to the superView along with some constraints

Example

import UIKit
class TestController: UIViewController {
    
   // creating some views
   let redView = UIView()
   let yellowView = UIView()
    
   override func viewDidLoad() {
      super.viewDidLoad()
      initialSetup()
   }    
   private func initialSetup() {
        
      view.backgroundColor = .white
      navigationItem.title = "UIView"
        
      // configuring the redView and adding it to the superView along with some constraints
      redView.backgroundColor = .red
      redView.translatesAutoresizingMaskIntoConstraints = false
      redView.layer.cornerRadius = 6
      redView.clipsToBounds = true
      view.addSubview(redView)
      redView.heightAnchor.constraint(equalToConstant: 150).isActive = true
      redView.widthAnchor.constraint(equalToConstant: 150).isActive = true
      redView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 100).isActive = true
      redView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
            
      // configuring the yellowView and adding it to superView along with some constraints
      yellowView.backgroundColor = .yellow
      yellowView.translatesAutoresizingMaskIntoConstraints = false
      yellowView.layer.cornerRadius = 6
      yellowView.clipsToBounds = true
      view.addSubview(yellowView)
      yellowView.heightAnchor.constraint(equalToConstant: 150).isActive = true
      yellowView.widthAnchor.constraint(equalToConstant: 150).isActive = true
      yellowView.topAnchor.constraint(equalTo: redView.bottomAnchor, constant: 50).isActive = true
      yellowView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
   }
}

Output

Once you run the above code, you will see both the subviews are displaying on the main screen. Here is the output.

If you want to remove all subviews from a view but keep the view itself, you can add the below code like this −

func removeAllSubviews() {
    
   // perform a loop to iterate each subView
   view.subviews.forEach { subView in
        
   // removing subView from its parent view
      subView.removeFromSuperview()
   }
}

This code uses a forEach method to iterate over the subviews array of parentView and remove each subview from parentView. The difference between this code and the previous code is that it uses a closure to call removeFromSuperview() on each subview instead of a for loop.

Once you run the above code, you will see both subviews disappear from the main screen. Here is the output −

Here are some more examples that involve removing subviews based on specific conditions

Example 1: Remove all Subviews of a Specific Type

Let's say you have a parentView that contains several subviews of different types, such as UILabel, UIButton, and UIImageView. You want to remove all the UILabel subviews. You can use the following code to accomplish this −

for case let label as UILabel in parentView.subviews {
   label.removeFromSuperview()
}

This code uses a for loop with a case let pattern matching syntax to iterate over the subviews array of parentView. The case let syntax checks whether each subview is an instance of UILabel. If the subview is a UILabel, its removeFromSuperview() method is called to remove it from parentView.

Example 2: Remove all Subviews that Meet Certain Criteria

For example, you have a parentView that contains many subviews of different types. You want to remove all subviews that have a specific property value. For example, let's say you want to remove all UIButton subviews with a title property equal to "Delete". You can use the following code to accomplish this −

for case let button as UIButton in parentView.subviews where button.title(for: .normal) == "Delete" {
   button.removeFromSuperview()
}

This code uses a for loop with a case let pattern matching syntax and a where clause to iterate over the subviews array of parentView. The case let syntax checks whether each subview is an instance of UIButton. The where clause checks whether the title property of the button is equal to "Delete". If both conditions are true, the button's removeFromSuperview() method is called to remove it from parentView.

Conclusion

In conclusion, there are several ways to remove all subviews of a view in Swift. You can use a for loop, a while loop, a guard statement, or a recursion to remove each subview from the view hierarchy. The method you choose will depend on your specific needs and coding style. Regardless of the method you use, make sure to test your code thoroughly to ensure that it works as expected.