Send a DEBUG log message @param tag @param msg

Send an INFO log message @param tag @param msg

@param index Index into the color array of the color to display in the progress spinner.

@return The amount the progress spinner is currently rotated, between [0..1].

Send a VERBOSE log message. @param tag @param msg

绘制stick

Send an ERROR log message @param tag @param msg

Do real refresh work. If there is a hook, execute the hook first. @param ignoreHook

perform UI after refresh

prepare for loading @param frame

@param show Set to true to show the arrow head on the progress spinner.

If the start / end trim are offset to begin with, store them so that animation starts from that offset.

Scroll back to to if is not under touch

Check can do refresh or not. For example the content is empty or the first child is in view.

Default implement for check can perform pull to refresh @param frame @param content @param header @return

将dip或dp值转换为px值，保证尺寸大小不变

将dip或dp值转换为px值，保证尺寸大小不变

Proceed to the next available ring color. This will automatically wrap back to the beginning of colors.

if deltaY > 0, move the content down @param deltaY

perform refreshing UI

When the content view has reached top and refresh has been completed, view will be reset. @param frame

Do refresh complete work when time elapsed is greater than {@link #mLoadingMinTime}