Android Question Tabstrip + Scrollview + Keyboard = Height?

JohnC

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I am using a Tabstrip and a few of the tab's pages have edittext controls on them.

So, I am forced to use a scrollview on each tabstrip page that has a edittext on it to make sure they can be visible when the keyboard is shown.

So, then I am forced to use IME to detect when the keyboard switches show/hide states so I can adjust the viewport size of the scrollview.

But I am having a hard time figuring out how to set the sv.height to the proper height of the visible part of the current tab page.

I would like the tab titles to remain visible, so I need to figure out the height of the visible space between the bottom of the tab titles row and the top of the keyboard.

Any ideas?
 

Erel

B4X founder
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See the attached example.

The important code is:
B4X:
Sub EditText_FocusChanged (HasFocus As Boolean)
   If HasFocus Then
       FocusedField = Sender
       UpdateLayoutIfNeeded
   Else
       Dim FocusedField As EditText 'it will be uninitialized
   End If
End Sub

Private Sub ime_HeightChanged (NewHeight As Int, OldHeight As Int)
   If NewHeight < OldHeight Then
       KeyboardSize = OldHeight - NewHeight
   Else
       KeyboardSize = 0
   End If
   UpdateLayoutIfNeeded
End Sub

Private Sub UpdateLayoutIfNeeded
   If FocusedField.IsInitialized = False Then Return
   Dim LowestVisiblePointRelativeToSV As Int = 100%y - KeyboardSize - 50dip '50dip = tab height
   If FocusedField.IsInitialized Then
       Dim fieldBottom As Int = FocusedField.Top + FocusedField.Height + 2dip
       Dim p As Panel = FocusedField.Parent
       Dim sv As ScrollView = p.Parent
       sv.ScrollPosition = fieldBottom - LowestVisiblePointRelativeToSV
   End If
End Sub

Note that the event name of all EditTexts is EditText.
 

Attachments

  • TabStripWithScrollViews.zip
    11 KB · Views: 581
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JohnC

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Longtime User
Hi,

It seems like the OS will automatically scroll the sv to make sure the focused edittext is visible to the user, so I took a slightly different approach in a solution:

I first created a routine that will search for a view's parent scroll view. This way I didn't need a bunch of DIM's for all the different scrollviews in order to be able to work with just one of them.

B4X:
Sub GetParentScrollView (V As View) As Object
    'returns the scrollview that is parent to the passed view (or returns non scrollview object if not found/error)
    'this allows accessing a particular scrollview from among many contained in an activity without requiring a unique declaration for each scrollview
 
    Dim FoundIt As Boolean = False
 
    Do While FoundIt = False
     
        Dim P As Object
     
        Try
            P = V.parent
        Catch
            Return P
        End Try
 
        If P Is ScrollView Then
            FoundIt = True
        Else
            V = P
        End If

    Loop
 
    Return P
 
End Sub

Then I have this code in the keyboard event:

B4X:
Sub IME_HeightChanged(NewHeight As Int, OldHeight As Int)
 
    Dim R As Object
 
    Select Case tabIcon.CurrentPage
        Case 0
            R = Misc.GetParentScrollView(txtName)
        Case 2
            R = Misc.GetParentScrollView(txtTextMessage)
    End Select
 
    If R Is ScrollView Then
        sv = R
        sv.Height = NewHeight - ActionBar.Height - 50dip 'tab header height
    End If
 
End Sub

I was actually surprised to see that you also used a constant of '50' for the tab height when calculating the scrollview height because there is no "tabMain.height" property to use in a calculation. My thought was that using a fixed value would not be a good value to depend on because it could vary from device to device. But I guess it's not.
 
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