Swift - ScrollView最初没有加载

Question

我在viewDidLoad和didRotateFromInterfaceOrientation方法中使用以下代码。名为topScrollView的scrollView在初始启动时不滚动，但在旋转后滚动。 我错过了什么？

func setLayoutOfGraphs(){

    self.graphView.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y,  self.view.bounds.width, 0.5 * self.view.bounds.height )

    self.barGraphHostingView!.frame = CGRectMake(self.graphView.bounds.width, self.graphView.frame.origin.y, self.graphView.bounds.width, self.graphView.bounds.height)
    self.pieGraph = CPTXYGraph(frame: self.graphView.bounds)
    self.barGraph = CPTXYGraph(frame: CGRectMake(self.graphView.bounds.width, self.graphView.bounds.origin.y, self.graphView.bounds.width, self.graphView.bounds.height))

    self.scrollView1.contentSize = CGSizeMake(self.scrollView1.frame.size.width, 1000)
    self.scrollView2.contentSize = CGSizeMake(self.scrollView2.frame.size.width, 1000)
    self.topScrollView.frame = CGRectMake(self.topScrollView.frame.origin.x, self.topScrollView.frame.origin.y,  self.graphView.bounds.width, self.view.bounds.height*0.5 )
    self.topScrollView.backgroundColor = UIColor.yellowColor()
    self.topScrollView.contentSize =   CGSizeMake(self.topScrollView.frame.width * 2 ,self.topScrollView.bounds.height)
    self.pieGraph!.frame = self.graphView.bounds


}