As IOS developers know, Apple released SwiftUI few months ago
SwiftUI is a modern way to declare user interfaces for any Apple platform. Create beautiful, dynamic apps faster than ever before.
With SwiftUI your IOS application will follow the MVVM architectural pattern , In this article I’ll show you how to navigate in an IOS app by following this pattern.
Let’s suppose that we have a master-detail app which means a list with some details for each row
I’ll write all the code in one struct , just for rapidity sake , but it ‘s recommended to separate each view with a struct , to make it reusable.
1- NavigationView :
Let’s use the NavigationView in our application to make each row take us to another View, Again to make it easy our detail view will be just another Text with a different content
Our code will be :
Here i added a NavigationView with a bar title “Medium” , and i changed the view of each row to a NavigationLink , which will handle the user click to take him to the destination
Now when the user click on [Row 1] it will take him to the UI below :
So this is the first way to navigate from a page to another one using SwiftUI
Let’s suppose that we have a navigation bar item which should move us to another page to see the available categories , How to do this with SwiftUI ?
We need to call navigationBarItems modifier , this one has an action parameter , so when the user click on this bar item , the app will take him to the categories view
To deal with this , we need a boolean variable with the annotation @ State (this is one of the property wrappers that SwiftUI give us) , and now following the MVVM pattern , SwiftUI will listen to this variable changes to update the UI (in our case to show a sheet)
And it’s clear now that by changing the value of the boolean variable , the app will update the UI, so I will change it inside the navigationBarItem click action
let’s call it showCategoriesSheet and let’s initialize it with false
Enough of talk , let’s move to the code
And After clicking on the the navigationBarItem , the view will be updated to :
3- Conditionally show a view
If someone wants to show another view with a full presentation not modal presentation , he can use the @ State variable showCategoriesSheet to check on it and decide which view will be visible to the user
The code will be like the image below :
As you noticed , I moved the code inside the sheet block to the else block
And after clicking on the navigation bar item , the whole view will be changed to the view in the else block ( as the shown image)
4- Button & NavigationLink
conditional show is good in case of login / main page as example , because we won’t give to the user the ability to navigate back to the login page when he logged successfully.
Now maybe someone want to navigate to another page (View) , but instead of this modal presentation he needs a full presentation ,but with the NavigationView style
to get what i mean , i’m talking about this part :
it’s easy to do this using the NavigationLink , like we did in the first example , but the problem is when we want to move to another page using a button action (for example if we need to move to another page after doing some background jobs)
Well actually it is not a problem , we can use NavigationLink but with another signature which is :
NavigationLink(destination: _ , isActive: _ , label: _ )
This one take a Bindable variable (isActive) , so when isActive == true the link will be executed and it takes the user to the second page ( categories in our case )
Now i added a NavigationLink which contains an EmptyView , with a destination , this link will listen to showCategoriesSheet changes to update the UI , and the result after clicking on the bar item will be like the shown image. with the back button.
Again , it’s recommended to split your views , each view in a separate struct for reusability and maintainability sake
Also in my example i used a simple basic UI , but you can apply this in your complex UI
I’ll try to update this article if i found another use cases in future .