TestScreenManager

Added in 1.1.0

Kotlin |Java

public class TestScreenManager extends ScreenManager

java.lang.Object
↳	androidx.car.app.ScreenManager
	↳	androidx.car.app.testing.TestScreenManager

The ScreenManager that is used for testing.

This class will track the following usages of the ScreenManager throughout your test:

All the Screens pushed via push, or pushForResult.
All the Screens removed via, pop, popTo, or remove.

Summary

Public methods
`@NonNull List<Screen>`	`getScreensPushed()` Returns all the `Screen`s pushed via `push`, and `pushForResult`.
`@NonNull List<Screen>`	`getScreensRemoved()` Returns all the `Screen`s removed via `pop`, `popTo`, and `remove`.
`boolean`	`hasScreens()` Returns `true` if the `Screen` stack has any screens in it.
`void`	`pop()` Pops the top `Screen` from the stack.
`void`	`popTo(@NonNull String marker)` Removes screens from the top of the stack until a `Screen` which has the given `marker` is found, or the root has been reached.
`void`	`popToRoot()` Removes all screens from the stack until the root has been reached.
`void`	`push(@NonNull Screen screen)` Pushes the `screen` to the stack.
`void`	`pushForResult( @NonNull Screen screen, @NonNull OnScreenResultListener onScreenResultListener )` Pushes a `Screen`, for which you would like a result from, onto the stack.
`void`	`remove(@NonNull Screen screen)` Removes the `screen` from the stack.
`void`	`reset()` Resets the values tracked by this `TestScreenManager` and the `Screen` stack.

Inherited methods

From androidx.car.app.ScreenManager

`@NonNull Collection<Screen>`	`getScreenStack()` Returns the copy of the current screen stack as a type `Collection`
`int`	`getStackSize()` Returns the current stack size.
`@NonNull Screen`	`getTop()` Returns the `Screen` that is at the top of the stack.

Public methods

getScreensPushed

Added in 1.1.0

public @NonNull List<Screen> getScreensPushed()

Returns all the Screens pushed via push, and pushForResult.

The screens are stored in the order in which they were pushed, where the first screen in the list is the first screen that was pushed.

The screens will be stored until reset is called.

getScreensRemoved

Added in 1.1.0

public @NonNull List<Screen> getScreensRemoved()

Returns all the Screens removed via pop, popTo, and remove.

The screens are stored in the order in which they were removed, where the first screen in the list, is the first screen that was removed.

The screens will be stored until reset is called.

hasScreens

Added in 1.1.0

public boolean hasScreens()

Returns true if the Screen stack has any screens in it.

pop

public void pop()

Pops the top Screen from the stack.

If the top Screen is the only Screen in the stack, it will not be removed.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Throws
`java.lang.IllegalStateException`	if the current thread is not the main thread

popTo

public void popTo(@NonNull String marker)

Removes screens from the top of the stack until a Screen which has the given marker is found, or the root has been reached.

The root Screen will not be popped.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Throws
`java.lang.NullPointerException`	if `marker` is `null`
`java.lang.IllegalStateException`	if the current thread is not the main thread

See also
`setMarker`

popToRoot

public void popToRoot()

Removes all screens from the stack until the root has been reached.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Throws
`java.lang.IllegalStateException`	if the current thread is not the main thread

push

public void push(@NonNull Screen screen)

Pushes the screen to the stack.

If the screen pushed is already in the stack it will be moved to the top of the stack.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Throws
`java.lang.NullPointerException`	if `screen` is `null`
`java.lang.IllegalStateException`	if the current thread is not the main thread

pushForResult

public void pushForResult(
    @NonNull Screen screen,
    @NonNull OnScreenResultListener onScreenResultListener
)

Pushes a Screen, for which you would like a result from, onto the stack.

When the given screen finishes, the onScreenResultCallback will receive a callback to onScreenResult with the result that the pushed screen set via setResult.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Parameters
`@NonNull Screen screen`	the `Screen` to push on top of the stack
`@NonNull OnScreenResultListener onScreenResultListener`	the listener that will be executed with the result pushed by the `screen` through `setResult`. This callback will be executed on the main thread

Throws
`java.lang.NullPointerException`	if either the `screen` or the `onScreenResultCallback` are `null`
`java.lang.IllegalStateException`	if the current thread is not the main thread

remove

public void remove(@NonNull Screen screen)

Removes the screen from the stack.

If the screen is the only Screen in the stack, it will not be removed.

If the app's lifecycle is already in the DESTROYED state, this operation is a no-op.

Throws
`java.lang.NullPointerException`	if `screen` is `null`
`java.lang.IllegalStateException`	if the current thread is not the main thread

reset

Added in 1.1.0

public void reset()

Resets the values tracked by this TestScreenManager and the Screen stack.