Question

When I try to change the hidden value of a button with performSelectorOnMainThread this works:

[pictureButton performSelectorOnMainThread:@selector(setHidden:) withObject:NO waitUntilDone:YES];

But this:

[pictureButton performSelectorOnMainThread:@selector(setHidden:) withObject:YES waitUntilDone:YES];

Gives this error:

Cannot initialize a parameter of type 'id' with an rvalue of type 'signed char'

What kind of internal conversion occurs to create this error? And how can I solve this?

Answer 1

The parameter is named withObject:. A BOOL isn’t an object, but nil can be passed in, and NO is equivalent to it, so your first example works (by accident).

You have a few options, but the simplest is probably to use GCD and execute the setHidden: method in a block on the main thread instead.