NSScreencast Episode #97 Scrolling Nub

Scrolling Nub - NSScreencast

スクロールバーの実装

• dropbox app, instapaper (example)
• grabbable
  • highlight when grabbed
• loadView (<UITableViewDataSource, UITableViewDelegate>)
  • scrollingNub initWithFrame
  • self.scrollingNub.layer.cornerRadius = 12;
  • self.scrollingNub.alpha = 0;
  • [self.view addSubview:self.scrollingNub];
  • UIPanGestureRecognizer
    • action:@selector(onNubScrub:)
• onNubScrub
  • Math
    • BUGFIX: Use negative value
      • CGFloat minOffset = - self.tableView.contentInset.top;
  • self.scrubbing = YES/NO
  • [pan translationInView:self.view].y
  • [self.tableView setContentOffset:offset];
  • [pan setTranslation:CGPointZero inView:self.view];
• animateNumbAlpha
• hideNubAfterDelay
  • dispatch_after
• scrollViewDidScroll
  • [self repositionNub];
• scrollViewDidEndDragging
  • [self hideNubAfterDelay];
• scrollViewDidEndDecelerating
  • [self hideNubAfterDelay];
• percentageThroughContent
• nubY
• bounce at the bottom