Click on Camera Shutter using UIAutomator

Question

I am writing an Espresso test for my app, and am trying to automate clicking the shutter button after opening of a camera in my app.

I am using Espresso and UIAutomator in the Android Emulator. I managed to dump this UI in UIAutomatorViewer.

I can't figure out why I am unable to click on the shutter button using UIAutomator using this code:

public void clickCameraShutterButton() throws UiObjectNotFoundException
{
    UiDevice device = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation());
    UiSelector shutterSelector = new UiSelector().resourceId("com.android.camera:id/shutter_button");
    UiObject shutterButton = device.findObject(shutterSelector);
    shutterButton.click();
}

The camera just sits there, and the shutter button is never clicked. This is the stack trace I'm getting in the Android Studio monitor:

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.app.Activity.findViewById(int)' on a null object reference

Any advice would be appreciated.

Answer 1

This worked for me

@Before
public void setUp() {
    // Initialize UiDevice instance
    final Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
    mDevice = UiDevice.getInstance(instrumentation);
}

...


/**
 * @@Test comment here@@
 *
 * @throws Exception
 */
@Test
public void culebraGeneratedTest_CameraShutter() throws Exception {
    mDevice.findObject(By.res("com.android.camera2:id/shutter_button").desc("Shutter").clazz("android.widget.ImageView").text(Pattern.compile("")).pkg("com.android.camera2")).clickAndWait(Until.newWindow(), DEFAULT_TIMEOUT);
}

This test finds the shutter and clicks on it.

If you are interested this test was automatically generated using CulebraTester.