Class CarContext

java.lang.Object
com.codename1.car.CarContext
public final class CarContext extends Object

The live handle to a connected head unit. Created by the framework when a car connects and handed to CarApplication#onCreateRootScreen(CarContext) and to every CarActionListener. Use it to drive the head-unit back stack (pushScreen(CarScreen), popScreen()), surface transient messages (showToast(String)) and query driver-distraction limits.

The context delegates rendering to a platform com.codename1.car.spi.CarBridge. On the simulator and on ports without in-car projection the bridge is absent, so every method here is a harmless no-op and isConnected() returns false -- application code never needs platform ifs.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    finish()
    Tears down the in-car experience and dismisses the app from the head unit.
    int
    getGridItemLimit()
    Returns the maximum items the head unit will show in a CarGridTemplate, or 0 if unknown.
    int
    getListRowLimit()
    Returns the maximum rows the head unit will show in a CarListTemplate, or 0 if unknown.
    CarScreen
    getTopScreen()
    Returns the screen currently at the top of the in-car back stack, or null if none.
    boolean
    isConnected()
    Returns true while a head unit is connected and rendering.
    void
    popScreen()
    Pops the top screen, returning to the one beneath it.
    void
    pushScreen(CarScreen screen)
    Pushes a screen onto the head-unit back stack and renders it.
    void
    showToast(String message)
    Shows a short transient message on the head unit.
    void
    showToast(String message, int durationSeconds)
    Shows a transient message on the head unit for a requested duration.

    Methods inherited from class Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • isConnected

      public boolean isConnected()
      Returns true while a head unit is connected and rendering.

    • getTopScreen

      public CarScreen getTopScreen()
      Returns the screen currently at the top of the in-car back stack, or null if none.

    • pushScreen

      public void pushScreen(CarScreen screen)

      Pushes a screen onto the head-unit back stack and renders it. The previous screen is paused.

      Parameters
      • screen: the screen to show

    • popScreen

      public void popScreen()
      Pops the top screen, returning to the one beneath it. No effect when only the root remains.

    • finish

      public void finish()
      Tears down the in-car experience and dismisses the app from the head unit.

    • showToast

      public void showToast(String message)

      Shows a short transient message on the head unit.

      Parameters
      • message: the text to display

    • showToast

      public void showToast(String message, int durationSeconds)

      Shows a transient message on the head unit for a requested duration.

      Parameters

      • message: the text to display

      • durationSeconds: requested duration in seconds (the head unit may clamp it)

    • getListRowLimit

      public int getListRowLimit()

      Returns the maximum rows the head unit will show in a CarListTemplate, or 0 if unknown. Honour this when populating lists -- rows beyond the limit are dropped by the platform.

      Returns

      the row limit, or 0 if unknown

    • getGridItemLimit

      public int getGridItemLimit()

      Returns the maximum items the head unit will show in a CarGridTemplate, or 0 if unknown.

      Returns

      the grid item limit, or 0 if unknown