iOS Question How to set TableView Section Header size, color etc

[Derek Johnson]

I'm trying to set the Size, Color etc of the section headers in a Tableview.

It appears possible to do this using Objective-C but I can't figure out how.

[Short summary - to save you reading the whole thing, it turns out that you can't do this unless you are prepared to implement all the methods of a TableView in Objective C. ]

I thought it might be possible to replace a Section Header with a Label with this code

Sub ChangeSectionHeader(Table As TableView)
    Dim MyView As Label
    MyView.Initialize("Section")
    MyView.Text="Custom Header"
    MyView.Color=Colors.Blue
    MyView.Height=60dip
    MyView.TextColor=Colors.Red
 
    Try
        Dim no As NativeObject = Table
        no.RunMethod("willDisplayHeaderView:", Array (True,MyView,0))
    Catch
        Log(LastException)
    End Try
 
End Sub

but I get this exception when I try it:

<B4IExceptionWrapper: Error Domain=caught_exception Code=0 " Method not found: willDisplayHeaderView:, target: <UITableView: 0x17101600; frame = (357.838 248.686; 328.266 238); clipsToBounds = YES; hidden = YES; gestureRecognizers = <NSArray: 0x16d93b50>; layer = <CALayer: 0x16d8deb0>; contentOffset: {0, 387}; contentSize: {328.26596, 624.84717}>" UserInfo={NSLocalizedDescription= Method not found: willDisplayHeaderView:, target: <UITableView: 0x17101600; frame = (357.838 248.686; 328.266 238); clipsToBounds = YES; hidden = YES; gestureRecognizers = <NSArray: 0x16d93b50>; layer = <CALayer: 0x16d8deb0>; contentOffset: {0, 387}; contentSize: {328.26596, 624.84717}>}>

I think that I'm sending the message to the wrong object, but not sure.

What am I doing wrong?

 

[JanPRO]

I think as you can see, willDisplayHeaderView is not a method like you know from B4i, so you have to use obj inline code to catch the sub.

 

[Derek Johnson]

JanPro,

Thanks - I missed off the bit of Objective-C that I was trying to call:

#if objc
- (void)tableView:(UITableView *)tableView willDisplayHeaderView:(UIView *)view forSection:(NSInteger)section
{
    // Background color
    view.tintColor = [UIColor blackColor];

    // Text Color
    UITableViewHeaderFooterView *header = (UITableViewHeaderFooterView *)view;
    [header.textLabel setTextColor:[UIColor whiteColor]];

    // Another way to set the background color
    // Note: does not preserve gradient effect of original header
    // header.contentView.backgroundColor = [UIColor blackColor];
}

#end if

but this code is not being reached I think .

 

[JanPRO]

Right.

I have never used before, but you can try https://www.b4x.com/android/forum/threads/tableview-with-custom-items.51205/

Or try Obj code:

#If objc
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    return anyView;
}
#End If

 

[Derek Johnson]

Right.

I have never used before, but you can try https://www.b4x.com/android/forum/threads/tableview-with-custom-items.51205/

Thanks for this suggestion, I've looked at this article, and just tried it. I managed to work round most of the issues involving the section numbering by creating a real section header with no header title and no footer title, followed by a table item that is formatted to look like a section header. I also put tags on the table items so that I could distinguish between pseudo-headers and standard table items.

This is my code for setting up a Custom Section Header if anyone is interested:

p_TableView is a Globally defined tableview
objAnchor is a reference TextField used for positioning

Sub InsertHeader(SectionHeader As String)
  
    'This creates an invisible section divider and increments the section number
    p_TableView.AddSection("","")
  
    Dim tc As TableCell = p_TableView.AddSingleLine("")
    tc.Bitmap=Null
    tc.ShowSelection = False
  
    Dim p As Panel
    p.Initialize("")
    p.Width = objAnchor.Width
    p.Height = objAnchor.Height
    p.Tag="Header"

    Dim Myview As Label
    'Can set these as required
    Myview.Initialize("Header")
    Myview.Text=SectionHeader
    Myview.Color=Colors.white
    Myview.Height=objAnchor.Height
    Myview.TextColor=Colors.Red
  
    p.AddView(Myview,10dip,0,p.Width,p.Height)
    tc.CustomView = p
End Sub

One thing that I couldn't manage to achieve however was the effect whereby the current section header appears at the top of the scroll area as you scroll down to later sections.

[Edit added later: I've also discovered an issue when the device is rotated. The Panel and Label in the above example needs to be re-sized and moved. I've had to add code to remember the objects and then to update them in the Page_Resize event. Will update the example at some point]

I still couldn't figure out how to re-format the actual section headers using your Objective-C and my previous guesses.

#If objc
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    return anyView;
}
#End If

In the above code anyView is obviously undefined and I wasn't sure what to set it too.

 

[JanPRO]

I still couldn't figure out how to re-format the actual section headers using your Objective-C and my previous guesses.

Something like

#If objc
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
        UILabel*label =[[UILabel alloc] init];
    label.textColor =[UIColor blackColor];
    label.backgroundColor =[UIColor whiteColor];
    label.text = @"test";
   
    return label;
}
#End If

 

[narek adonts]

To make it work you shold change the tableview delegate to your module where you are using inline objc.

 

[Derek Johnson]

To make it work you should change the tableview delegate to your module where you are using inline objc.

Sorry - I can't figure out how to do that. Could you explain what that would look like - I've having great trouble understanding and working with delegates of objects.

 

[JanPRO]

Changing the tableview delegate

Dim NaObj As NativeObject = TableView1
NaObj.RunMethod("setDelegate:",Array(Me))
NaObj.RunMethod("setDataSource:",Array(Me))

means also, that the B4i methods for the TableView wouldn't work any more. So you have to do all operations for the tableview with inline objc code ...

 

[Derek Johnson]

means also, that the B4i methods for the TableView wouldn't work any more. So you have to do all operations for the tableview with inline objc code ...

Aargh!!

I don't think I'll be going down that route - sounds decidedly scary, but thanks for your patient help.