How to build a custom control in iOS
跟蹤用戶觸控,要重寫以下方法哼拔。
- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(nullable UIEvent *)event;
- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(nullable UIEvent *)event;
- (void)endTrackingWithTouch:(nullable UITouch *)touch withEvent:(nullable UIEvent *)event;?
- (void)cancelTrackingWithEvent:(nullable UIEvent *)event;