Hide and Unhide Toggle button - running very slow - excel

Question

I have a workbook with 12 sheets and I have placed one Command button in each sheet to hide/unhide rows. For hiding specific rows, I have typed "A" in coloumn A, for every row that needs to be hidden. So code works but it runs forever, takes long time and very slow in hidding or unhiding the rows. In some sheets total number of rows to check are 100 and some sheets it is 750. Please advice the reason for slow running or Is there a better way I can make it work faster. Here is the code:-
Private Sub CommandButton1_Click()
Sheet2.Unprotect ("aaa")
Dim rng As Range
Dim iRow As Range
Dim hidden_status As Boolean
CommandButton1.Caption = "Show / Hide Guidelines"
On Error Resume Next
Set rng = Range("A1:A750")
For Each iRow In rng.Rows
If iRow.Text = "A" Then
With iRow.EntireRow
hidden_status = .Hidden
.Hidden = Not hidden_status
End With
End If
Next iRow
On Error GoTo 0
Sheet2.Protect ("aaa")
End Sub

Answer 1

Each time you hide a row, Excel then is stopping to update your screen (and potentially perform calculations). So to help really speed things up, disable all the screen updates and application events (including calculations) until you've finished hiding.
So with a Sub like this:
Private Sub SetUpdates(ByVal newState As Boolean)
With Application
.ScreenUpdating = newState
.EnableEvents = newState
.DisplayAlerts = newState
End With
End Sub
You can do something like this:
Private Sub CommandButton1_Click()
SetUpdates newState:=False
'--- hide your rows here
SetUpdates newState:=True
End Sub

Answer 2

You could use AutoFilter.
This procedure will hide any row that doesn't contain a value in column A on whichever sheet reference is passed to it. If the filter is already applied it will remove it.
Public Sub HideA(wrkSht As Worksheet)
With wrkSht
If .FilterMode Then
.ShowAllData
Else
.Range("A1", .Cells(.Rows.Count, 1).End(xlUp)) _
.AutoFilter Field:=1, Criteria1:="=", VisibleDropDown:=False
End If
End With
End Sub
On each sheet that contains a button add this code for the button (renaming the procedure as required):
Private Sub CommandButton1_Click()
HideA ActiveSheet
End Sub
The one downside to this is that it doesn't include cell A1 in the filtering.