Fight with Programming

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 t...

To study how to draw some sort of figures such as lines and circles etc., and how to tap&drag those items, I developed a sample program referring to the official site of SkiaSharp and Inventing Events from Effects . In this sample program, correlation diagrams of novel characters can be easily created and editted.  Inputting characters group names in the 1st (main) page, they are listed in the ListView of the page.  If tap one of the name (the list item), move to the page where the correlation diagram of the tapped characters group can be created and editted. MainPage.xaml <? xml  version = " 1.0 "  encoding = " utf-8 "   ?> < ContentPage   xmlns = " http://xamarin.com/schemas/2014/forms "               xmlns : x = " http://schemas.microsoft.com/winfx/2009/xaml "               xmlns : views = " clr-name...