How can I get the last element using Xpath in Appium

Question

For example, I have message elements in my Android app and all of them have a resource-id called "message_view" . What I want is to get the last message with this resource-id using Xpath only. I have tried to use [last()] , but it does not work:

driver.findElement (By.xpath ("//*[contains(@resource-id,'message_view')][last()]"));

I know that I can use findElements() , and then .get(list.size() - 1) . But I want to understand how can I do this with Xpath only.

Answer 1

In Xpaths, [] has a higher precedence over // , so in your given Xpath, the last() doesn't work because it's being executed first rather than last. Use a pair of parenthesis in order to force this to work as you expect:

(//*[contains(@resource-id,'message_view')])[last()]

Answer 2

You need to wrap locator with () , as it was mentioned in another answer.

I will explain difference between //locator[last()] and (//locator)[last()]

Let's imagine you have following DOM:

<div>
  <div>
   <p1></p1> // 1
   <p1></p1> // 2
  </div>
  <div>
   <p1></p1> // 3
   <p1></p1> // 4
  </div>
</div>

With //p1[last()] you'll find all p1 elements, that ARE last elements in their nodes (last of siblings), so it's 2nd and 4th p1 element.

By (//locator)[last()] locator, you'll find all p1 nodes, and pick the last one (which will be actually the last p1 node in DOM), so it's 4th p1 element.