使用UIGestureRecognizer下面的代碼:在iOS上,爲什麼UIGestureRecognizer可以實例化,如果它是抽象類?
UIGestureRecognizer *gestureRecog = [[UIGestureRecognizer alloc]
initWithTarget:self
action:@selector(handletap:)];
[self.view addGestureRecognizer:gestureRecog];
實際上可以編譯和運行。我以爲abstract class不能被實例化?