Now, let’s look at our three navigation goals again:

Where am I?

By hiding the navigation in child-views the user no longer knows which top-level page of the app he/she is in. Users lose the position in your overall information architecture.

By hiding the navigation in child-views the user no longer knows which top-level page of the app he/she is in. Users lose the position in your overall information architecture. Where else can I go?

By hiding other top-level pages users can no longer directly navigate to other areas of the app. Instead they first have to navigate back to the top level of the information architecture.

By hiding other top-level pages users can no longer directly navigate to other areas of the app. Instead they first have to navigate back to the top level of the information architecture. What will I find when I get there?

The only navigation element in the child screen is a small left-arrow without a label or description. It doesn’t tell a user where he/she will go by clicking it.

Medium might have had the best intentions when they did include a tab navigation. And so did thousands of other iOS and Android apps. It works perfectly on top-level views, but their execution failed to meet every single goal of a navigation in child-views.

The child-view behaves like a modal-view by overlaying the overall navigation (tab bar), but it animates like a child-view (right to left) and displays a back-link (arrow) like a child-view. Modality isn’t a bad thing at all. “Modality creates focus by preventing people from doing other things until they complete a task or dismiss a message or view” (Apple). But modality also requires the usage of modal animations (iOS: animating from the bottom into the screen) and including completion and cancel buttons to exit the modal view. Modal views are only used for short-term tasks that are self-contained processes and can be either completed or canceled, like writing a mail, adding an event to a calendar, dismissing a notification, … They are not intended to be used as a detail-view or to replace a child-view. Those child views are not a self-contained process and they can neither be canceled nor saved.

Would you like to know more about the use of modality? The following article will explain the concept in more detail:

One could argue that there are exemptions to this restrictive use of modality, e.g. for fullscreen detail-views like a single photo. Hiding the app’s overall UI (like tab bar) creates focus and minimises distraction. In this case, a custom transition is often used to explain the uncommon use of modality. While a Medium article could be considered a fullscreen detail-view that lacks a custom transition and close-functionality the app’s settings-view definitely can’t be.