B4J Question Getting started ...

[Brian Dean]

I have done several projects with B4A. Now I am trying out B4J but I always have trouble getting started, partly because I don't usually use Layouts and I am trying to use them with B4J. This time I want to fill MainForm with a scrollable canvas. Here is my code ...

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("main")     ' Loads a scrollpane
    scrMain.LoadLayout("canvas", -1, -1)     ' Loads a canvas anchored to parent's extents
    ' Do something to see if this worked ...
    Dim p As Paint = fx.Colors.Green
    cvs.DrawCircle(200, 200, 200, p, True, 0)
    MainForm.Show
End Sub

This is the result ...

.

The canvas does not fill the scrollpane. In the Layout Designer the parent of the canvas is "Main", which is not what I want. But I can see another problem ahead when I want to extend the canvas beyond the scrollpane boundary. How should I be doing this?

 

[klaus]

Sorry, but you don't give enough information!
It would be much easier for us to help you if you posted your project as a zip file.
That way, we see what exactly you have done and how, and we can test your project as you do !!!

 

[EnriqueGonzalez]

when dealing with scrollpane you have an innerNode property.

scrMain.innerNode

then you have prefWidth and prefHeight

scrMain.innerNode.prefWidth = 700
scrMain.innerNode.prefWidth = 600

 

[Brian Dean]

Sorry, but you don't give enough information!

@klaus - Yes, I thought that you might say that. I have stripped out just the main form and here it is ...

 

[klaus]

Move the drawing in the MainForm_Resize routine.
In AppStart the dimensions of the view is not known.
Attached a modified version of your project.
What do you need the ScrollPane for, you don't set the dimensions of the InnerNode bigger than the ScrollPane view !?

 

[Brian Dean]

In AppStart the dimensions of the view is not known.

Thanks for explaining - I can understand that. I will move forward now to my next problem. Best regards.

 

[Brian Dean]

... then you have prefWidth and prefHeight

@Enrique Gonzalez R : Thanks for the pointer - I am making progress now.