ios - Adjust UIScrollView's contentSize with an embedded UIView? -

i have uiscroll view contains 1 subview. subview called contentviewis uiview. here did in viewdidload():

self.scrollview = uiscrollview() self.view.addsubview(self.scrollview) self.scrollview.backgroundcolor = uicolor.yellowcolor()  // pin edges edges of superview (self.view) self.scrollview.snp_makeconstraints { (make) -> void in   make.edges.equalto(self.view) }  // create contentview self.contentview = uiview() self.contentview.backgroundcolor = uicolor.redcolor() self.scrollview.addsubview(self.contentview)  // pin edges of contentview scrollview self.contentview.snp_makeconstraints { (make) -> void in   make.edges.equalto(self.scrollview)  }  let myview = uiview(frame: cgrectmake(100, 100, 20, 300)) myview.backgroundcolor = uicolor.greencolor() self.contentview.addsubview(myview) 

the result this:

there ne red contentview shown in previous screen shot.

next, tried adjust size of contenview in viewdidlayoutsubviews():

let newsize: cgsize = self.contentview.systemlayoutsizefittingsize(uilayoutfittingcompressedsize) println("newsize: \(newsize)") 

the result is:

newsize: (0.0, 0.0) 

how can either setup correct size of contentview or set correct size of uiscrollview's contentsize?

have tried setting var contentsize: cgsize of uiscrollview? documentation says

discussion
unit of size points. default size cgsizezero.

if don't know size of content view, recommend setting

scrollview.autoresizingmask = (uiviewautoresizingflexiblewidth| uiviewautoresizingflexibleheight); 

and

scrollview.autoresizessubviews = yes; 

for measure.