Tap & Drag on ScrollView (1)
In the previous post, Drawing (1) , I developed an Xamarin.Forms App that draws correlation diagrams of novel characters. In other word, the App can display graph data, which nodes are ContextView corresponding to novel characters and linked each other. At that time, I tried to use ScrollView to be able to show a large correlation diagram including many novel characters. But it's not so easy, because tap & drag are stolen by ScrollVIew. I googled and googled, but nothing seem to make sense. So I made it possible to Tap & Drag on ScrollView in a pseudo way. The point is content size of ScrollView. In ScrollView, scroll is enable if content size is larger than window (display) size. But, on the contrary, if content size is smaller than window size, scroll is disable (Naturally!). Besides, while scroll is disable, Tap & Drag is not stolen by ScrollView. So, the following simple procedure, Reduce content size of ScrollView to window (display) size when Contex