UISwitch: what is done earlier:attached selector, or change of state?

Question

Say, I have created an instance of UISwitch programmatically:

    UISwitch *switchBtn = [[UISwitch alloc] initWithFrame:CGRectMake(200, 10, 0, 0)];
    [switchBtn setOn:YES animated:YES];
    [switchBtn addTarget:self action:@selector(switchStateChanged:) forControlEvents:UIControlEventValueChanged];

Then, if I press that switch while application runs, what will be performed earlier: switchStateChanged, or the change of value of switchBtn.on?

Answer 1

For future visitors. As I found out after some obvious experimentation, in XCode 6.1.1, state of UISwitch is changed earlier than attached method is performed.

Answer 2

The UISwitch, when the user manipulates the switch control (“flips” it) a UIControlEventValueChanged event is generated, which results in the control (if properly configured) sending an action message.

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