Loop through subview to check for empty UITextField - Swift - ios

Question

I"m wondering how to essentially transform the objective c code below into swift.
This will loop through all the subviews on my desired view, check if they are textfields, and then check if they are empty of not.
for (UIView *view in contentVw.subviews) {
NSLog(#"%#", view);
if ([view isKindOfClass:[UITextField class]]) {
UITextField *textfield = (UITextField *)view;
if (([textfield.text isEqualToString:""])) {
//show error
return;
}
}
}
Here is where i am with swift translation so far:
for view in self.view.subviews as [UIView] {
if view.isKindOfClass(UITextField) {
//...
}
}
Any help would be great!

Answer 1

Update for Swift 2 (and later): As of Swift 2/Xcode 7 this can be simplified.
Due to the Objective-C "lightweight generics", self.view.subviews
is already declared as [UIView] in Swift, therefore the cast
is not necessary anymore.
Enumeration and optional cast can be combined with to a for-loop
with a case-pattern.
This gives:
for case let textField as UITextField in self.view.subviews {
if textField.text == "" {
// show error
return
}
}
Old answer for Swift 1.2:
In Swift this is nicely done with the optional downcast operator as?:
for view in self.view.subviews as! [UIView] {
if let textField = view as? UITextField {
if textField.text == "" {
// show error
return
}
}
}
See "Downcasting"
in the Swift book.

Answer 2

Swift 5 and Swift 4: -
A Very simple answer you can understand easyly : - You can handle all kind of Objects like UILable, UITextfields, UIButtons, UIView, UIImages . any kind of objecs etc.
for subview in self.view.subviews
{
if subview is UITextField
{
//MARK: - if the sub view is UITextField you can handle here
if subview.text == ""
{
//MARK:- Handle your code
}
}
if subview is UIImageView
{
//MARK: - check image
if subview.image == nil
{
//Show or use your code here
}
}
}
//MARK:- You can use it any where, where you need it
//Suppose i need it in didload function we can use it and work it what do you need
override func viewDidLoad() {
super.viewDidLoad()
for subview in self.view.subviews
{
if subview is UITextField
{
//MARK: - if the sub view is UITextField you can handle here
if subview.text == ""
{
//MARK:- Handle your code
}
}
if subview is UIImageView
{
//MARK: - check image
if subview.image == nil
{
//Show or use your code here
}
}
}
}