Understanding basics of iOS uiautomation selector strategy for Appium

I am writing UI automation tests for an iOS native app using Appium and gradually realizing how most of the element locating strategies don't reliably work for iOS.

Apart from XPath which randomly works, other options that I have are:

• Accessibility ID (did not work for me)
• name (not every element will have value for 'name' attribute)
• class (makes sense when you are working with a list of elements)
• iOS UiAutomation predicates (steep learning curve for beginners)

I have been trying to understand how to use iOS UiAutomation locator strategy and find elements using it but it's not working on Appium Inspector. I have referred to these documentations (Appium iOS Predicate reference, Apple UIAutomation reference) but I feel they cater to an advanced Appium user audience who have some knowledge on iOS development, not for beginners.

Currently the element hierarchy that I am trying to find element in is something like this:

My current automation setup is:

• XCode 6.3.2
• Appium 1.4.8
• iOS 8.3
• Appium Java Client 3.1.0

What will be the locator I can use to locate the highlighted element using UiAutomation predicate strategy? I have been trying a few options on the Appium Inspector like:

• applications()[0].windows()[0].navigationBars()[0].textFields().withPredicate("value == 'Search eBay'")
• .textFields().withPredicate("value == 'Search eBay'")

These did not work. What am I doing wrong here? Are there any other documentations which clearly explain iOS UiAutomation locators from ground-up? It will really help if someone can explain these basics.