Fix tab button layout on mobile

[stuartmscott]

Description:

Tab buttons were always rendered in a grid of columns, this PR uses a grid of rows when the tab location is leading or trailing

Checklist:

• Tests included.
• Lint and formatter run with no errors.
• Tests all pass.

[andydotxyz]

Thanks, but not quite the complete solution - 2 cases seem wrong.

Mobile, Portrait, Leading - tabs appear at bottom (should be top)
Mobile, Landscape, Bottom - tabs appear at left (leading), but should be right

[stuartmscott]

Where are you getting these expectations from?

From the ticket (#1310), AppTabs is a combination of two Material Design components;

• Bottom Navigation - which, as the name, suggests doesn't appear at the top.
• Navigation Rail - "The navigation rail is placed on the left side of the screen for left-to-right languages, and on the right side of the screen for right-to-left languages."

[andydotxyz]

Where are you getting these expectations from?

From how it worked before?

[stuartmscott]

From how it worked before?

I don't think that is true, Fyne v2.0.0 AppTab on Mobile always moved Leading & Trailing to Bottom (https://github.com/fyne-io/fyne/blob/master/container/apptabs.go#L323):

func (r *appTabsRenderer) adaptedLocation() TabLocation {
	tabLocation := r.container.tabLocation
	if fyne.CurrentDevice().IsMobile() && (tabLocation == TabLocationLeading || tabLocation == TabLocationTrailing) {
		return TabLocationBottom
	}

	return r.container.tabLocation
}

And does not have different behaviour for Mobile Portrait vs Mobile Landscape

[andydotxyz]

Fyne v2.0.0 AppTab on Mobile always moved Leading & Trailing to Bottom

Strange, seems I misremembered how it was previously working.

I misremembered how it used to work, needs re-testing