import android.support.test.uiautomator.Direction; //导入依赖的package包/类

/**

* Navigates through the focus items in a container returning the container child that has a

* descendant matching the {@code selector}.

*

* The navigation starts in the {@code direction} specified and

* {@link Direction#reverse(Direction) reverses} once if needed. Fails if there is not a

* focused

* descendant, or if after completing both directions no focused child has a descendant

* matching

* {@code selector}.

*

* Fails if the menu item can not be navigated to.

*

* @param uiDevice the device under test.

* @param container contains children to navigate over.

* @param selector the selector for the object to navigate to.

* @param direction the direction to start navigating.

* @return the object navigated to.

*/

public static UiObject2 assertNavigateTo(UiDevice uiDevice, UiObject2 container,

BySelector selector, Direction direction) {

int count = 0;

while (count < 2) {

BySelector hasFocusedDescendant = By.hasDescendant(FOCUSED_VIEW);

UiObject2 focusedChild = null;

SearchCondition untilHasFocusedDescendant = Until

.hasObject(hasFocusedDescendant);

boolean result = container.wait(untilHasFocusedDescendant,

UiObject2Asserts.getAdjustedTimeout(Constants.MAX_SHOW_DELAY_MILLIS));

if (!result) {

// HACK: Try direction anyways because play control does not always have a

// focused item.

UiDeviceUtils.pressDpad(uiDevice, direction);

UiObject2Asserts.assertWaitForCondition(container, untilHasFocusedDescendant);

}

for (UiObject2 c : container.getChildren()) {

if (c.isFocused() || c.hasObject(hasFocusedDescendant)) {

focusedChild = c;

break;

}

}

if (focusedChild == null) {

Assert.fail("No focused item found in container " + container);

}

if (focusedChild.hasObject(selector)) {

return focusedChild;

}

if (!UiObject2Utils.hasSiblingInDirection(focusedChild, direction)) {

direction = Direction.reverse(direction);

count++;

}

UiDeviceUtils.pressDpad(uiDevice, direction);

}

Assert.fail("Could not find item with " + selector);

return null;

}