Question

Can you explain this assignment? What does it mean?

boolean activityExists = testIntent.resolveActivity(pm) != null;

Answer 1

It means to assign true if testIntent.resolveActivity(pm) does not return null otherwise assigns false.

Understandable long form of this would be

boolean activityExists;
if(testIntent.resolveActivity(pm) != null) {
    activityExists = true;
} else {
    activityExists = false;
}