How to check element properties in iOS gui automation?

Question

All UI Automation examples I've seen uses standard components whose state can be inspected with the JavaScript API using the value() method. This is a bit limiting. Lets say you want to check the color or alpha value and whatnot.

How can I inspect the properties of a view?

An example: a tap on a certain element should make it "selected". I'd like to perform a tap on it and then verify that isSelected is TRUE.

Update:

I found the withPredicate() method which should do it in theory, except it seems to only trigger on name properties:

element.withPredicate("isSelected == YES")          // always fails
element.withPredicate("name matches 'my element'")  // works

Answer 1

I ended up with this approach which works for my purposes:

Let UIView.accessibilityValue return a JSON string with relevant properties:

- (NSString *)accessibilityValue
{
    return [NSString stringWithFormat:
            @"{'alpha':%f, 'isSelected':%@}", 
            self.alpha, self.isSelected ? @"true" : @"false"];
}

Then use eval() in the test code and check those properties. value() is shorthand for calling accessibilityValue:

var props = eval("(" + element.value() + ")");

if (props.isSelected) {
    UIALogger.logFail("Should not be selected");
}

UIATarget.localTarget().tap({"x":471, "y":337});

var props = eval("(" + element.value() + ")");

if (!props.isSelected) {
    UIALogger.logFail("Should be selected");
}