NavigationStack

Provides a stack of Pages with navigation. More...

Import Statement: import VPlayApps 1.0
Inherits:

Item

Properties

Signals

Methods

Detailed Description

The NavigationStack item manages the navigation of hierarchical content represented by a stack of Pages.

Basic Usage

The pages presented by a NavigationStack item typically represent a hierarchical organization of the displayed data. At each level of the hierarchy, a custom Page component represents the content of the currently displayed screen.

As an example a simple hierachical settings app can look like the following:

The first page (the root screen) displays a list of main setting groups. The individual detail pages with the settings for a setting group can be pushed by calling the push() method of the associated NavigationStack item.

As an example, to push the General page after selecting the according row you can call:

 navigationStack.push(detailPage)

A third page in the stack and all other following can be pushed accordingly.

Note: If you plan to use the split view feature (which is enabled by default on tablets) you should use popAllExceptFirstAndPush() instead of push() for the first level page pushes within your navigation stack:

 navigationStack.popAllExceptFirstAndPush(detailPage)

Note: This only applies to the first pages right after the initial page, for all other pushes you still use push().

You can also set additional properties for a newly pushed page, like in the following example for which an additional boolean property of the pushed detail page is set:

 navigationStack.push(detailPage, { showAdvancedSettings: true })

Note: As seen in the previous two examples every Page item has a convenience property called navigationStack which is set to the parent NavigationStack item, if contained in any.

To navigate back to a previous page you can either use the provided back button in the NavigationBar. This back button is provided for all pages pushed to the stack except the root page. As an alternative (e.g. when you decided to hide the navigation bar on a specific page) you can also implement your own interaction element and call pop() on the NavigationStack item.

Split View on Tablets

The NavigationStack component supports a tablet optimized visualization that automatically uses a two pane layout on devices with a diameter of more than 5 inches. The previous settings example looks like the following on a tablet:

When splitView is enabled, the first page of your NavigationStack is shown in the left pane of the split layout, regardless of the currently pushed pages.

Note: As noted above make sure to use popAllExceptFirstAndPush() instead of push() for pushing the first level pages for the right pane.

For more details on how to enable and disable the split view feature have a look at splitView.

Property Documentation

[read-only] canNavigateBack : bool

Use this property to determine if one of either the currentPage or the leftColumnPage allow to navigate back. If it is true, Page::backNavigationEnabled is true for one of these pages and it is possible to open a previous page. The NavigationStack automatically shows a back button in the NavigationBar and allows to go back with the hardware back button if this is the case.

Calling pop() will always go to back to the previous page, even if the Page::backNavigationEnabled setting wouldn't allow it.

See also pop().


[read-only] currentPage : Page

The currently shown page on top of the navigation stack.

See also currentTitle.


[read-only] currentTitle : string

The title of the currently displayed page on top of the stack.

See also currentPage.


[read-only] depth : int

Use this readonly property to get the number of items currently pushed onto the stack. This property is if there is only the initial page on the stack.


initialPage : var

The first Page that is shown initially. Must be a QML item derived from Page.

If no initial page is set, the first Page item that is a child of the NavigationStack will be used as the initial page.

The following two definitions have the same effect:

 NavigationStack {
   // initial page as child item
   Page { title: "initial page" }
 }
 NavigationStack {
   // initial page set via property
   initialPage: Page { title: "initial page" }
 }

[read-only] leftColumnBar : NavigationBar

Use this readonly property to get a reference to the internal NavigationBar item for the left column when using splitView mode.

This QML property was introduced in V-Play 2.6.2.


leftColumnIndex : int

Usually the initial Page item within a NavigationStack is used as the left pane content when using the splitView layout.

There might be cases where you want to pin another page as the left content item. For that you can set this property to another index value of your page stack.

Note: This is an advanced setting, in most cases the default value of 0 is sufficient.


[read-only] leftColumnPage : var

The currently displayed page in the left column if using the splitView layout.


leftColumnWidth : real

Set this property to control the width of the left split view column when using the splitView layout.

By default this property is set to 300 dp or using at least one third of the width when below.


Use this readonly property to get a reference to the internal NavigationBar item used by this navigation stack.


splitView : bool

Set this property to explicitely use or disable the split view feature of NavigationStack. In split view mode the NavigationStack uses a two column layout.

By default the split view feature is deactivated. To use the split view only on devices with a diameter of equally or greater than 5 inches, simply set:

 NavigationStack {
   // Use splitview only on tablets
   splitView: tablet
 }

You can also enable it for all devices by setting the property to true or disable it with false. It's also possible to use more advanced settings like in the following example:

 NavigationStack {
   // Use splitview only in landscape mode on tablets
   splitView: tablet && landscape
 }

See also splitViewActive and leftColumnWidth.


[read-only] splitViewActive : bool

You can use this readonly property to determine if the pages are currently shown with a split view layout.

Note: This property is only true if splitView is true, the navigation-stack is visible and the depth is greater than the leftColumnIndex.


[read-only] transitioning : bool

True, if a push or pop transition animation is currently running.


Signal Documentation

popped(Item page)

Emitted after a Page has been popped from the stack.


pushed(Item page)

Emitted after a Page has been pushed from the stack.


transitionFinished()

Emitted after the push or pop transition animation have finished.


Method Documentation

clearAndPush(source, options)

Clear the whole stack and show a new page.

Useful if a new top-level navigation is selected.


bool contains(Page page)

Returns true, if the passed page is inside the NavigationStack.


Page getPage(int index, bool dontLoad)

Return the Page at the specified index of the stack. The index must be between 0 and depth - 1.

dontLoad is an optional argument, passed to StackView::get.


void pop(var options)

Pop from the NavigationStack.

options is an optional argument, passed to StackView::pop.


popAllExceptFirst()

Pop all pages except the first. Useful to remove all pages on the right side of a multi-column splitView layout.

Note: The page that at the position of the leftColumnIndex is considered the first page. Usually this is the page with index 0.


popAllExceptFirstAndPush(source, options)

Clears all pages except the first, then pushes a new one.

Note: The page that at the position of the leftColumnIndex is considered the first page. Usually this is the page with index 0.

Internally this function calls popAllExceptFirst() and then push(). This is useful if a navigation happens from the left column of a multi-column layout, as it pushes a page as top-level item in the right column.


void push(var source, var options)

Push a Page onto the NavigationStack.

source can be either an URL to a QML file, a Component or a Page object. Note that it is not advised to directly push items.

options is any JS object used as properties for the created object, if source is an url or a Component.


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