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Working with watchOS Navigation in Xamarin

  • Artikkeli

The simplest navigation option available on the watch is a simple modal popup that appears on top of the current scene.

For multi-scene watch apps there are two navigation paradigms available:

Use the PresentController method to open an interface controller modally. The interface controller must already be defined in the Interface.storyboard.

PresentController ("pageController","some context info");

Modally-presented controllers use the entire screen (covering the previous scene). By default the title is set to Cancel and tapping it will dismiss the controller.

To programmatically close the modally-presented controller, call DismissController.

DismissController();

Modal screens can be either a single scene or use a page-based layout.

Hierarchical Navigation

Presents scenes like a stack that can be navigated back through, similar to the way UINavigationController works on iOS. Scenes can be pushed onto the navigation stack and popped off (either programmatically or by user-selection).

Scenes can be pushed onto the navigation stack Scenes can be popped off of the navigation stack

As with iOS, a left-edge-swipe navigates back to the parent controller in a hierarchical navigation stack.

Pushing and Popping in Code

Watch Kit does not require an over-arching "navigation controller" to be created like iOS does - simply push a controller using the PushController method and a navigation stack will automatically be created.

PushController("secondPageController","some context info");

The watch's screen will include a back button in the top left, but you can also programmatically remove a scene from the navigation stack using PopController.

PopController();

As with iOS, it is also possible to return to the root of the navigation stack using PopToRootController.

PopToRootController();

Using Segues

Segues can be created between scenes in the storyboard to define hierarchical navigation. To get context for the target scene, the operating system calls GetContextForSegue to initialize the new interface controller.

public override NSObject GetContextForSegue (string segueIdentifier)
{
  if (segueIdentifier == "mySegue") {
    return new NSString("some context info");
  }
  return base.GetContextForSegue (segueIdentifier);
}

Page-Based Interfaces

Page-based interfaces swipe left-to-right, similar to the way UIPageViewController works on iOS. Indicator dots are displayed along the bottom of the screen to show which page is currently displayed.

Sample first page Sample second page Sample fifth page

To make a page-based interface the main UI for your watch app, use ReloadRootControllers with an array of interface controllers and contexts:

var controllerNames = new [] { "pageController", "pageController", "pageController", "pageController", "pageController" };
var contexts = new [] { "First", "Second", "Third", "Fourth", "Fifth" };
ReloadRootControllers (controllerNames, contexts);

You can also present a page-based controller that is not the root using PresentController from one of the other scenes in an app.

var controllerNames = new [] { "pageController", "pageController", "pageController", "pageController", "pageController" };
var contexts = new [] { "First", "Second", "Third", "Fourth", "Fifth" };
PresentController (controllerNames, contexts);