Revert "一个ScrollView下拉刷新的Demo"

This reverts commit b9a5565a23d110d02cadc2ba0b74380f61e1b810.
Revert "Revert "一个ScrollView下拉刷新的Demo""

This reverts commit 4fb3702429a34c60d4bdb3e38d9c45a127f7e278.