拖曳滑动

类似凤凰网拖曳滑动效果:

http://code4app.com/ios/ifengNewsOrderDemo/53159e83933bf0473e8b5d08

类似网易新闻拖曳滑动效果:

http://code4app.com/ios/%E7%BD%91%E6%98%93%E6%96%B0%E9%97%BB%E5%AE%A2%E6%88%B7%E7%AB%AF%E7%BF%BB%E9%A1%B5%E5%8A%A8%E7%94%BB%E6%95%88%E6%9E%9C-qq%E6%B0%94%E6%B3%A1%E6%B6%88%E6%81%AF%E6%8B%96%E6%8B%BD%E6%95%88%E6%9E%9C/55bb1f19594b90cc718b79ce