Force instrumented activity run in multi-window mode

Question

As you know, android provided Multi-Window support mode in android N. Our application has multi-window support.
But how to test it? How to force test run the app in that mode? I haven't founded any such method in Instrumentation class or anywhere else in documentation. Maybe it is somehow possible with Espresso?

Answer 1

Unfortunately the way provided by azizbekian requires an app which has been loaded in multi-window mode previously, so I want to provide own solution. At the answer I have found how to enter multi-window mode programmatically. Using it I built the complete solution:

    UiAutomation uiAutomation = InstrumentationRegistry.getInstrumentation().getUiAutomation();
    //enter multi-window mode
    uiAutomation.performGlobalAction(AccessibilityService.GLOBAL_ACTION_TOGGLE_SPLIT_SCREEN);
    //wait for completion, unfortunately waitForIdle doesn't applicable here
    Thread.sleep(1000);
    //simulate selection of our activity
    MotionEvent motionDown = MotionEvent.obtain(SystemClock.uptimeMillis(), SystemClock.uptimeMillis(), KeyEvent.ACTION_DOWN,
            150, 200, 0);
    motionDown.setSource(InputDevice.SOURCE_TOUCHSCREEN);
    uiAutomation.injectInputEvent(motionDown, true);
    motionDown.recycle();
    MotionEvent motionUp = MotionEvent.obtain(SystemClock.uptimeMillis(), SystemClock.uptimeMillis(), KeyEvent.ACTION_UP,
            150, 200, 0);
    motionUp.setSource(InputDevice.SOURCE_TOUCHSCREEN);
    uiAutomation.injectInputEvent(motionUp, true);
    motionUp.recycle();
    //perform test actions below

As you can see, there are two workarounds:

1. We can't use uiAutomation.waitForIdle to wait entering multi-mode completion
2. I haven't found a way to select an application in task manager to request focus to our activity. So I just perform some touch event on the possible location of our activity.

After implementing it you'll be able to test the activity as usual with Espresso etc.