Android Excel File Reader Application using Basic4Android - Tutorial Part 2

Submitted by donbermoy on Thursday, January 16, 2014 - 15:09.
This is my continuation of my tutorial in creating a an Excel File Reader Application in Basic4Android. My part 1 tutorial is the creation of our main program but you have to add a class module and named it as "Table". To add a class module follow the picture below.
Here's the complete code of our table.bas and write this code together with my main code in the first tutorial in Creating Excel File Reader Application in Android.
Sub Class_Globals
        Private StringUtils1 As StringUtils
        Private SV As ScrollView
        Public Header As Panel
        Private Callback As Object
        Private Event As String
        Private SelectedRow As Int
        Private Data As List
        Private LabelsCache As List
        Private minVisibleRow, maxVisibleRow As Int
        Private visible As Boolean
        Private visibleRows As Map
        Public NumberOfColumns, ColumnWidth As Int
        Public RowHeight, HeaderColor, TableColor, FontColor, HeaderFontColor As Int
        Public FontSize As Float
        Type RowCol (Row As Int, Col As Int)
        Public Alignment As Int
        Public SelectedDrawable(), Drawable1(), Drawable2() As Object
        'Table settings
        HeaderColor = Colors.Gray
        RowHeight = 30dip
        TableColor = Colors.LightGray
        FontColor = Colors.Black
        HeaderFontColor = Colors.White
        FontSize = 14
        Alignment = Gravity.LEFT 'change to Gravity.LEFT or Gravity.RIGHT for other alignments.
End Sub
 
Public Sub Initialize (CallbackModule As Object, EventName As String, vNumberOfColumns As Int)
        SV.Initialize2(0, "SV")
        SV.Panel.Color = TableColor
        Callback = CallbackModule
        Event = EventName
        innerClearAll(vNumberOfColumns)
End Sub
 
'Clears the table
Public Sub ClearAll
        innerClearAll(NumberOfColumns)
End Sub
 
'Sets the columns widths.
'Example: <code>Table1.SetColumnsWidths(Array As Int(100dip, 30dip, 30dip, 100%x - 160dip))</code>
Public Sub SetColumnsWidths(Widths() As Int)
        Dim v As View
        For i = 0 To Widths.Length - 1
                v = Header.GetView(i)
                v.Width = Widths(i) - 1dip
                If i > 0 Then
                        v.Left = Header.GetView(i-1).Left + Widths(i-1) + 1dip
                End If
        Next
        Dim lbls() As Label
        For i = 0 To visibleRows.Size - 1
                lbls = visibleRows.GetValueAt(i)
                For lbl = 0 To lbls.Length - 1
                        lbls(lbl).SetLayout(Header.GetView(lbl).Left, lbls(lbl).Top, _
                                Header.GetView(lbl).Width, RowHeight)
                Next
        Next
End Sub
 
Private Sub innerClearAll(vNumberOfColumns As Int)
        For i = SV.Panel.NumberOfViews -1 To 0 Step -1
                SV.Panel.RemoveViewAt(i)
        Next
        NumberOfColumns = vNumberOfColumns
        Dim Drawable1(NumberOfColumns) As Object
        Dim Drawable2(NumberOfColumns) As Object
        Dim SelectedDrawable(NumberOfColumns) As Object
        For i = 0 To NumberOfColumns - 1
                Dim cd1, cd2, cd3 As ColorDrawable
                cd1.Initialize(Colors.White, 0)
                cd2.Initialize(0xFF98F5FF, 0)
                cd3.Initialize(0xFF007FFF, 0)
                Drawable1(i) = cd1
                Drawable2(i) = cd2
                SelectedDrawable(i) = cd3
        Next
        SV.Panel.Height = 0
        SelectedRow = -1
        minVisibleRow = -1
        maxVisibleRow = 0
        Data.Initialize
        LabelsCache.Initialize
        visibleRows.Initialize
        SV.ScrollPosition = 0
        DoEvents
        SV.ScrollPosition = 0
        For i = 1 To 80 'fill the cache to avoid delay on the first touch
                LabelsCache.Add(CreateNewLabels)
        Next
        If visible Then
                SV_ScrollChanged(0)
        End If
End Sub
 
Private Sub SV_ScrollChanged(Position As Int)
        Dim currentMin, currentMax As Int
        currentMin = Max(0, Position / RowHeight - 30)
        currentMax = Min(Data.Size - 1, (Position + SV.Height) / RowHeight + 30)
        If minVisibleRow > -1 Then
                If minVisibleRow < currentMin Then
                        'need to hide the upper rows
                        For I = minVisibleRow To Min(currentMin - 1, maxVisibleRow)
                                HideRow(I)
                        Next
                Else If minVisibleRow > currentMin Then
                        'need to show the upper rows
                        For I = currentMin To Min(minVisibleRow - 1, currentMax)
                                ShowRow(I)
                        Next
                End If
                If maxVisibleRow > currentMax Then
                        'need to hide the lower rows
                        For I = maxVisibleRow To Max(currentMax + 1, minVisibleRow) Step -1
                                HideRow(I)
                        Next
                Else If maxVisibleRow < currentMax Then
                        'need to show the lower rows
                        For I = currentMax To Max(maxVisibleRow + 1, currentMin) Step -1
                                ShowRow(I)
                        Next
                End If
        End If
        minVisibleRow = currentMin
        maxVisibleRow = currentMax
End Sub
 
'Adds the tablet to the activity.
Public Sub AddToActivity(Act As Activity, Left As Int, Top As Int, Width As Int, Height As Int)
        visible = True
        Header.Initialize("")
        Header.Color = TableColor
        Act.AddView(Header, Left, Top , Width, RowHeight)
        Act.AddView(SV, Left, Top + RowHeight, Width, Height - RowHeight)
        ColumnWidth = SV.Width / NumberOfColumns
        
        SV_ScrollChanged(0)
 
End Sub
 
'Adds a row to the table
'Example:<code>Table1.AddRow(Array As String("aaa", "ccc", "ddd", "eee"))</code>
Public Sub AddRow(Values() As String)
        If Values.Length <> NumberOfColumns Then
                Log("Wrong number of values.")
                Return
        End If
        Data.Add(Values)
        Dim lastRow As Int
        lastRow = Data.Size - 1
        If lastRow < (SV.ScrollPosition + SV.Height) / RowHeight + 1 Then
                ShowRow(lastRow)                
        End If
        SV.Panel.Height = Data.Size * RowHeight
End Sub
 
Public Sub RemoveRow(Row As Int)
        SV_ScrollChanged(SV.ScrollPosition)
        Dim sr As Int = SelectedRow
        SelectRow(-1)
        Data.RemoveAt(Row)
        If Data.Size = 0 Then
                ClearAll
                Return
        End If
        For i = minVisibleRow To maxVisibleRow
                HideRow(i)
        Next
        maxVisibleRow = Min(maxVisibleRow, Data.Size - 1)
        minVisibleRow = Min(minVisibleRow, Data.Size - 1)
        For i = minVisibleRow To maxVisibleRow
                ShowRow(i)
        Next
        If sr = Row Then
                sr = -1
        Else If sr > Row Then
                sr = sr - 1
        End If
        SelectRow(sr)
        SV.Panel.Height = Data.Size * RowHeight
        SV_ScrollChanged(Min(SV.ScrollPosition, SV.Panel.Height))
End Sub
 
Private Sub ShowRow(row As Int)
        If visibleRows.ContainsKey(row) Then Return
        'Log("ShowRow: " & row)
        Dim lbls() As Label
        Dim values() As String
        lbls = GetLabels(row)
        values = Data.Get(row)
        visibleRows.Put(row, lbls)
        Dim rowColor() As Object
        If row = SelectedRow Then
                rowColor = SelectedDrawable
        Else If row Mod 2  = 0 Then
                rowColor = Drawable1
        Else
                rowColor = Drawable2
        End If
        For I = 0 To lbls.Length - 1
                SV.Panel.AddView(lbls(I), Header.GetView(I).Left, row * RowHeight, Header.GetView(I).Width, _
                        RowHeight - 1dip)
                lbls(I).Text = values(I)
                lbls(I).Background = rowColor(I)
        Next
End Sub
 
Private Sub IsRowVisible(Row As Int) As Boolean
        Return Row < (SV.ScrollPosition + SV.Height) / (RowHeight + 1) AND _
                Row > SV.ScrollPosition / RowHeight
End Sub
 
Private Sub HideRow (Row As Int)
        'Log("HideRow: " & row)
        Dim lbls() As Label
        lbls = visibleRows.Get(Row)
        If lbls = Null Then 
                Log("HideRow: (null) " & Row)
                Return
        End If
        For I = 0 To lbls.Length - 1    
                lbls(I).RemoveView
        Next
        visibleRows.Remove(Row)
        LabelsCache.Add(lbls)
End Sub
 
Private Sub GetLabels(Row As Int) As Label()
        Dim lbls() As Label
        If LabelsCache.Size > 0 Then
                'Log("from cache")
                lbls = LabelsCache.Get(LabelsCache.Size - 1)
                LabelsCache.RemoveAt(LabelsCache.Size - 1)
        Else
                lbls = CreateNewLabels          
        End If
        For I = 0 To lbls.Length - 1
                Dim rc As RowCol
                rc = lbls(I).Tag
                rc.Row = Row
        Next
        Return lbls
End Sub
 
Private Sub CreateNewLabels As Label()
        Dim lbls(NumberOfColumns) As Label
        For I = 0 To NumberOfColumns - 1
                Dim rc As RowCol
                rc.Col = I
                Dim l As Label
                l.Initialize("cell")
                l.Gravity = Alignment
                l.TextSize = FontSize
                l.TextColor = FontColor
                l.Tag = rc
                lbls(I) = l
        Next
        Return lbls
End Sub
'Set the headers values
'Example:<code>Table1.SetHeader(Array As String("Col1", "Col2", "Col3"))</code>
Public Sub SetHeader(Values() As String)
        For I = Header.NumberOfViews - 1 To 0 Step -1
                Header.RemoveViewAt(I)
        Next
        For I = 0 To NumberOfColumns - 1
                Dim l As Label
                l.Initialize("header")
                l.Gravity = Gravity.CENTER
                l.TextSize = FontSize
                l.Color = HeaderColor
                l.TextColor = HeaderFontColor
                l.Text = Values(I)
                l.Tag = I
                Header.AddView(l, ColumnWidth * I, 0, ColumnWidth - 1dip, RowHeight)
        Next
End Sub
 
Private Sub Cell_Click
        Dim rc As RowCol
        Dim l As Label
        l = Sender
        rc = l.Tag
        SelectRow(rc.Row)
        If SubExists(Callback, Event & "_CellClick") Then
                CallSub3(Callback, Event & "_CellClick", rc.Col, rc.Row)
        End If
End Sub
 
Private Sub Header_Click
        Dim l As Label
        Dim col As Int
        l = Sender
        col = l.Tag
        If SubExists(Callback, Event & "_HeaderClick") Then
                CallSub2(Callback, Event & "_HeaderClick", col)
        End If
End Sub
 
'Gets the value of the given cell.
Public Sub GetValue(Col As Int, Row As Int)
        Dim values() As String
        values = Data.Get(Row)
        Return values(Col)
End Sub
'Sets the value of the given cell.
Public Sub SetValue(Col As Int, Row As Int, Value As String)
        Dim values() As String
        values = Data.Get(Row)
        values(Col) = Value
        If visibleRows.ContainsKey(Row) Then
                Dim lbls() As Label
                lbls = visibleRows.Get(Row)
                lbls(Col).Text = Value
        End If
End Sub
 
Private Sub SelectRow(Row As Int)
        Dim prev As Int
        prev = SelectedRow
        SelectedRow = Row
        'remove the color of previously selected row
        If prev > -1 Then
                If visibleRows.ContainsKey(prev) Then
                        HideRow(prev)
                        ShowRow(prev)
                End If
        End If
        SelectedRow = Row
        For col = 0 To NumberOfColumns - 1
                If visibleRows.ContainsKey(SelectedRow) Then
                        HideRow(SelectedRow)
                        ShowRow(SelectedRow)
                End If
        Next
End Sub
 
'Makes the given row visible.
Public Sub JumpToRow(Row As Int)
        SV.ScrollPosition = Row * RowHeight
End Sub
 
'Clears the previous table and loads the CSV file to the table.
'You should first add the Table to the activity before calling this method.
Public Sub LoadTableFromCSV(Dir As String, Filename As String, HeadersExist As Boolean)
        
        Dim List1 As List
        Dim h() As String
        If HeadersExist Then
                Dim headers As List
                List1 = StringUtils1.LoadCSV2(Dir, Filename, ",", headers)
                Dim h(headers.Size) As String
                For i = 0 To headers.Size - 1
                        h(i) = headers.Get(i)
                Next
        Else
                List1 = StringUtils1.LoadCSV(Dir, Filename, ",")
                Dim firstRow() As String
                firstRow = List1.Get(0)
                Dim h(firstRow.Length)
                For i = 0 To firstRow.Length - 1
                        h(i) = "Col" & (i + 1)
                Next
        End If
        innerClearAll(h.Length)
        ColumnWidth = SV.Width / NumberOfColumns
        SetHeader(h)
        For Each row() As String In List1
                AddRow(row)
        Next
End Sub
 
'Saves the table to a CSV file.
Public Sub SaveTableToCSV(Dir As String, Filename As String)
        Dim headers(NumberOfColumns) As String
        Dim i As Int
        For Each l As Label In Header
                headers(i) = l.Text
                i = i + 1
        Next
        StringUtils1.SaveCSV2(Dir, Filename, ",", Data, headers)
End Sub
 
Public Sub Size As Int
        Return Data.Size
End Sub
Please read the comment in the code (color "green") to understand what that code means. And then now you come up with an Excel File Reader that can view an Excel File. Best regards, Engr. Lyndon R. Bermoy IT Instructor/System Developer/Android Developer STI College - Surigao City 09126450702 [email protected] Follow and add me in my Facebook Account: www.facebook.com/donzzsky. I can also make thesis and documentation. Just contact the number above. Visit my page on Facebook at: https://www.facebook.com/BermzISware
Comments

TUTORIAL ON TABLEVIEW AND SQLITE

Thanks. Can you also do a tutorial on how to display data from sqlite db to tableview? thanks
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