Multi: Refactor MasterPage and PageStack

[ukane-philemon]

Closes #249

-- Refactor app.NewMasterPage to accept and handle a start page.
-- Refactor *app.MasterPage.Display()
-- Refactor app.PageStack.Push to only prepare the next page.
-- Refactor pages that embed app.Masterpage.
-- Refactor app.PageStack.Pop()
-- Fix some TODOs.

[ukane-philemon]

Forwarding User Interaction should happen after a new page has been assigned if we hit the tab changed if branch. Same thing applies to other master pages.

[dreacot]

@ukane-philemon i'm not fully sure what the scope of this PR aims to achieve or it's necessity

[ukane-philemon]

@ukane-philemon i'm not fully sure what the scope of this PR aims to achieve or it's necessity

Mainly this "Refactor app.NewMasterPage to accept and handle a start page.". This way we don't have to check if pg.CurrentPage() == nil everywhere when we can initialize with a page.

[JustinBeBoy]

@ukane-philemon i'm not fully sure what the scope of this PR aims to achieve or it's necessity

Mainly this "Refactor app.NewMasterPage to accept and handle a start page.". This way we don't have to check if pg.CurrentPage() == nil everywhere when we can initialize with a page.

I agree with @dreacot , I'm not sure about the purpose of this PR, your PR and the current PR are not much different.

• Current code: Whenever we create a new master page, obviously pg.CurrentPage() will be nil, instead of checking we will always create a page for it.
• Your PR: Add a page when creating the master page but that is optional, it does not prevent pg.CurrentPage() from being nil if the page is not initialized for the master page, If the page passed in is mandatory then there would be no need to check pg.CurrentPage() == nil

This PR I see is just another approach but the problem is still not solved as you said

[ukane-philemon]

Your PR: Add a page when creating the master page but that is optional, it does not prevent pg.CurrentPage() from being nil if the page is not initialized for the master page, If the page passed in is mandatory then there would be no need to check pg.CurrentPage() == nil

Yes, most of the master pages don't need to check as they always have a start page. Only the Window's masterPage and dex masterPage check for a nill CurrentPage() and with #238, we can tell which page to display from the onset for the dex masterPage.

[dreacot]

moving to backlog

[ukane-philemon]

I'll resubmit if this is needed in the future.