Android Question Add drag and drop to multiple views

[apty]

I am creating panels programatically based on number of entries in a database table, e.g if the table has 10 entries, i create 10 panels. Now i want the panels to be draggable around the screen. I have tried the DraggableView class but i keep getting NullPointerException error. Below is my code, please assist

Dim Cursor1 As Cursor=sql1.ExecQuery("SELECT foodname,imaged FROM tastes")
        Dim ttrow As Int=Cursor1.RowCount
    Dim dv(ttrow) As DraggableView
For i = 0 To Cursor1.RowCount - 1
        Cursor1.Position = i
'        Log("************************")
  
      Dim pnl As Panel
 
    pnl.Initialize("pnl2")
        pnl.LoadLayout("panel1")
  
         dv(i).Initialize(Activity, pnl)
Activity.AddView(pnl,lft,tp,Activity.Width/5,Activity.Width/5+20dip)
Next

 

[Erel]

Please post the full error message and the line that causes it.

pnl.LoadLayout("panel1")

This will not crash your program but it is a mistake. You need to add the panel to its parent before you load the layout. Otherwise the panel size is not known.

 

[apty]

ok thanks Erel. I managed to do it by also initializing the draggable view after Activity.Adview...

By the way, i realised after adding the draggable view i can't get the pnl2_Click event. If i remove the draggableview, the click event works. How can i get the panel click event with the draggable view?

 

[Erel]

The touch event is consumed by the transparent panel that is added above the view. You will need to modify DraggableView class and decide how to treat the touch events.

GestureDetector library might help here.

 

[apty]

i modified the class and included a click event as shown below but it still doesn't work. I can only drag and drop but clicking on the panels doesn't do anything

Sub Initialize(Activity As Activity, v As View)
   innerView = v
   panel1.Initialize("pnl2")
   panel1.Color = Colors.Transparent
   Activity.AddView(panel1, v.Left, v.Top, v.Width, v.Height)
   ACTION_DOWN = Activity.ACTION_DOWN
   ACTION_MOVE = Activity.ACTION_MOVE
   ACTION_UP = Activity.ACTION_UP
   'action_click=activity.
   Dim r As Reflector
   r.Target = panel1
  r.SetOnClickListener("IV_onClick")
   r.SetOnTouchListener("Panel1_Touch") 'why reflection instead of the regular Panel_Touch event? Good question which deserves a forum thread of its own (not related to classes)...
End Sub

Private Sub Panel1_Touch (o As Object, action As Int, x As Float, y As Float, motion As Object) As Boolean
   If action = ACTION_DOWN Then
      downx = x
      downy = y
   Else
      innerView.Left = innerView.Left + x - downx
      innerView.Top = innerView.Top + y - downy     
      panel1.Left = innerView.Left
      panel1.Top = innerView.Top
   End If
   Return True
End Sub

Public Sub IV_onClick(o As Object)
    Msgbox("This click has been trapped by your class", "Clicked")
End Sub

 

[Erel]

It doesn't work because the touch event already consumes the touch gesture.

 

[apty]

How should i do it?

 

[Erel]

https://www.b4x.com/android/forum/threads/lib-gesture-detector.21502/#content

 

[apty]

The library has touch event but no click event. Are they the same?

 

[Erel]

I'm not an expert with this library. The first thing that you need to test is whether it works together with the Touch event that you are already using. If so then it should be easy to find the appropriate gesture.

 

[Smee]

@apty were you able to solve this? a