# UiController

`public interface UiController`
``

android.support.test.espresso.UiController

Provides base-level UI operations (such as injection of `MotionEvent`s) that can be used to build user actions such as clicks, scrolls, swipes, etc. This replaces parts of the android Instrumentation class that provides similar functionality. However, it provides a more advanced synchronization mechanism for test actions. The key differentiators are:

- test actions are assumed to be called on the main thread
- after a test action is initiated, execution blocks until all messages in the main message queue have been cleared.

## Summary

### Public methods
`abstract boolean` | `injectKeyEvent(KeyEvent event)` Injects a key event into the application.
`abstract boolean` | `injectMotionEvent(MotionEvent event)` Injects a motion event into the application.
`abstract boolean` | `injectString(String str)` Types a string into the application using series of `KeyEvent`s.
`abstract void` | `loopMainThreadForAtLeast(long millisDelay)` Loops the main thread for a specified period of time.
`abstract void` | `loopMainThreadUntilIdle()` Loops the main thread until the application goes idle.

## Public methods

### injectKeyEvent

    boolean injectKeyEvent (KeyEvent event)

Injects a key event into the application.

Parameters
`event` | `KeyEvent`: the (non-null!) event to inject

Returns
`boolean` | true if the event was injected, false otherwise

Throws
`InjectEventSecurityException` | if the event couldn't be injected because it would interact with another application.

### injectMotionEvent

    boolean injectMotionEvent (MotionEvent event)

Injects a motion event into the application.

Parameters
`event` | `MotionEvent`: the (non-null!) event to inject

Returns
`boolean` | true if the event was injected, false otherwise

Throws
`InjectEventSecurityException` | if the event couldn't be injected because it would interact with another application.

### injectString

    boolean injectString (String str)

Types a string into the application using series of `KeyEvent`s. It is up to the implementor to decide how to map the string to `KeyEvent` objects. if you need specific control over the key events generated use `injectKeyEvent(KeyEvent)`.

Parameters
`str` | `String`: the (non-null!) string to type

Returns
`boolean` | true if the string was injected, false otherwise

Throws
`InjectEventSecurityException` | if the events couldn't be injected because it would interact with another application.

### loopMainThreadForAtLeast

    void loopMainThreadForAtLeast (long millisDelay)

Loops the main thread for a specified period of time. Control may not return immediately, instead it'll return after the time has passed and the queue is in an idle state again.

Parameters
`millisDelay` | `long`: time to spend in looping the main thread

### loopMainThreadUntilIdle

    void loopMainThreadUntilIdle ()

Loops the main thread until the application goes idle. An empty task is immediately inserted into the task queue to ensure that if we're idle at this moment we'll return instantly.

- ## Interfaces

  - BaseLayerComponent
  - EspressoException
  - FailureHandler
  - IdlingResource
  - IdlingResource.ResourceCallback
  - UiController
  - ViewAction
  - ViewAssertion
  - ViewFinder
  - ViewInteractionComponent

- ## Classes

  - AmbiguousViewMatcherException.Builder
  - DataInteraction
  - Espresso
  - GraphHolder
  - IdlingPolicies
  - IdlingPolicy
  - NoMatchingViewException.Builder
  - PerformException.Builder
  - Root
  - Root.Builder
  - ViewInteraction

- ## Exceptions

  - AmbiguousViewMatcherException
  - AppNotIdleException
  - IdlingResourceTimeoutException
  - InjectEventSecurityException
  - NoActivityResumedException
  - NoMatchingRootException
  - NoMatchingViewException
  - PerformException