Check if nsbutton is intersected for a certain number of seconds

Question

I have a cursor object and I want to be able to tell when it intersects an nsbutton, and whether it does continuously for a 3 seconds. My code works except that when the cursor comes near a button, it freezes until it has been three seconds and then logs "Button overlapped for 3 seconds".

   NSDate* date;
   -(BOOL)checkIfIntersects :(NSButton*)button {

      BOOL intersects =  CGRectIntersectsRect (cursor.frame,button.frame);

      if (intersects) {
         date = [NSDate date];

        while (intersects) {
            if ([date timeIntervalSinceNow] < -1)
            {
                NSLog(@"Button overlapped for 3 seconds");

                break;
            }
            intersects =  CGRectIntersectsRect (cursor.frame,button.frame);      
       }

    }

    return NO;

}

Answer 1

This is because your thread is stuck inside the while(intersects) loop, only exiting after the internal if statement is satisfied. This will hang your entire thread.

The quickest/easiest solution for you would be to have an interaction flag outside of your function along with your NSDate.

  NSDate* momentIntersectionBegan = nil;
  BOOL intersectedPreviously = false;

  -(BOOL)checkIfIntersects :(NSButton*)button {
     BOOL currentlyIntersects =  CGRectIntersectsRect (cursor.frame,button.frame);

  if (currentlyIntersects) {
    if(intersectedPreviously){
        if ([momentIntersectionBegan timeIntervalSinceNow] < -3)
        {
            NSLog(@"Button overlapped for 3 seconds");
        }
    }else{
        momentIntersected = [NSDate date];
    }
      intersectedPreviously = true;
  }else{
      intersectedPreviously = false;
  } 

return NO;

}