Interface CarBridge

public interface CarBridge

Internal service-provider interface implemented by each platform port to render the portable com.codename1.car template tree onto the native in-car UI (Apple CarPlay's CPTemplate hierarchy or Google Android Auto's androidx.car.app templates).

Application code never touches this interface -- it is obtained by the com.codename1.car framework classes from com.codename1.ui.Display#getCarBridge() and driven through the public com.codename1.car.CarContext / com.codename1.car.CarScreen API. The base implementation returns null, which is why the public API degrades to a harmless no-op on the simulator and on ports without an in-car projection (so application code needs no platform if statements).

A bridge renders a screen by pulling its template through CarScreen.createTemplate() (the framework calls CarScreen#dispatchCreateTemplate() on its behalf) and is responsible for invoking the relevant com.codename1.car.CarActionListener when the user activates a row, grid item or action -- the bridge identifies the activated element by the indices it assigned while rendering.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    finish()
    Tears down the in-car experience, dismissing the app from the head unit.
    int
    getGridItemLimit()
    Returns the maximum number of items the head unit will display in a single grid, or 0 when the limit is unknown.
    int
    getListRowLimit()
    Returns the maximum number of rows the head unit will display in a single list, or 0 when the limit is unknown.
    void
    invalidate(CarScreen screen)
    Re-pulls and re-renders the template for the supplied screen (call after mutating the model behind a screen, mirroring androidx.car.app.Screen#invalidate()). No effect if the screen is not currently on the stack.
    boolean
    isConnected()
    Returns true while a head unit (CarPlay / Android Auto) is currently connected and the projected UI is live.
    void
    popScreen()
    Pops the top screen off the in-car back stack, returning to the previous screen.
    void
    pushScreen(CarScreen screen)
    Pushes a screen onto the in-car back stack and renders its template.
    void
    showToast(String message, int durationSeconds)
    Shows a short transient message on the head unit (CarPlay banner / Android Auto toast).

  • Method Details

    • pushScreen

      void pushScreen(CarScreen screen)

      Pushes a screen onto the in-car back stack and renders its template. The pushed screen becomes the visible top of stack.

      Parameters
      • screen: the screen to push and render

    • popScreen

      void popScreen()
      Pops the top screen off the in-car back stack, returning to the previous screen. Has no effect when only the root screen remains.

    • invalidate

      void invalidate(CarScreen screen)

      Re-pulls and re-renders the template for the supplied screen (call after mutating the model behind a screen, mirroring androidx.car.app.Screen#invalidate()). No effect if the screen is not currently on the stack.

      Parameters
      • screen: the screen whose template should be rebuilt

    • finish

      void finish()
      Tears down the in-car experience, dismissing the app from the head unit.

    • isConnected

      boolean isConnected()

      Returns true while a head unit (CarPlay / Android Auto) is currently connected and the projected UI is live.

      Returns

      true if a car is connected

    • showToast

      void showToast(String message, int durationSeconds)

      Shows a short transient message on the head unit (CarPlay banner / Android Auto toast).

      Parameters

      • message: the text to display

      • durationSeconds: requested display duration in seconds; the head unit may clamp it

    • getListRowLimit

      int getListRowLimit()

      Returns the maximum number of rows the head unit will display in a single list, or 0 when the limit is unknown. Driver-distraction rules cap this aggressively (often 6-12); honour it when populating a com.codename1.car.CarListTemplate.

      Returns

      the row limit, or 0 if unknown

    • getGridItemLimit

      int getGridItemLimit()

      Returns the maximum number of items the head unit will display in a single grid, or 0 when the limit is unknown.

      Returns

      the grid item limit, or 0 if unknown