Button placed on selected TListItem in most cases

问题:

I have a Firemonkey TListBox in an Android app and in OnPaint I place 3 buttons on the selected TListBoxItem. They are being displayed and all have a OnClick event assigned. But when clicking them this event usually does not fire. Only seldom I get the button clicked.

I guess the TListBox already received the click and declared it as handled. Is there any way otherwise? Can I register a tap in the form itsself and determine from the position of the tap which of the buttons must have been pressed? How would that work?

Here's the code of the current solution, the TListBox is client aligned to the form and the buttons in the TLayout are right aligned.

unit MainForm;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, 
  System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, 
  FMX.Dialogs, FMX.Layouts, FMX.ListBox, FMX.Controls.Presentation, 
  FMX.StdCtrls, FMX.Objects;

type
  TForm1 = class(TForm)
    lb_Files: TListBox;
    Layout1: TLayout;
    Image1: TImage;
    Image2: TImage;
    Button1: TButton;
    Button2: TButton;
    Rectangle1: TRectangle;
    Rectangle2: TRectangle;
    procedure FormCreate(Sender: TObject);
    procedure lb_FilesPaint(Sender: TObject; Canvas: TCanvas;
      const ARect: TRectF);
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
  public
  end;

var
  Form1: TForm1;

implementation

uses
  System.UIConsts;

{$R *.fmx}

procedure TForm1.Button1Click(Sender: TObject);
begin
  lb_Files.ListItems[lb_Files.ItemIndex].Text := 'Info';
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  lb_Files.ListItems[lb_Files.ItemIndex].Text := 'Test';
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  i : Integer;
begin
  for i := 0 to 30 do
    lb_Files.Items.Add('File' + i.ToString +'.dat');
end;

procedure TForm1.lb_FilesPaint(Sender: TObject; Canvas: TCanvas;
  const ARect: TRectF);
begin
  if lb_Files.ItemIndex > -1 then
  begin
    Layout1.Parent  := lb_Files.ListItems[lb_Files.ItemIndex];
    Layout1.Align   := TAlignLayout.Right;
    Layout1.Visible := true;
  end;
end;

end.

Here is the FMX content's now:

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 480
  ClientWidth = 640
  StyleBook = StyleBook1
  FormFactor.Width = 320
  FormFactor.Height = 480
  FormFactor.Devices = [Desktop]
  OnCreate = FormCreate
  DesignerMasterStyle = 3
  object lb_Files: TListBox
    Align = Client
    Enabled = False
    Size.Width = 640.000000000000000000
    Size.Height = 480.000000000000000000
    Size.PlatformDefault = False
    StyleLookup = 'listboxstyle'
    TabOrder = 0
    OnPaint = lb_FilesPaint
    DisableFocusEffect = True
    DefaultItemStyles.ItemStyle = 'listboxitemstyle'
    DefaultItemStyles.GroupHeaderStyle = ''
    DefaultItemStyles.GroupFooterStyle = ''
    Viewport.Width = 640.000000000000000000
    Viewport.Height = 480.000000000000000000
    object Layout1: TLayout
      Position.X = 384.000000000000000000
      Position.Y = 192.000000000000000000
      Size.Width = 153.000000000000000000
      Size.Height = 50.000000000000000000
      Size.PlatformDefault = False
      TabOrder = 0
      object Rectangle1: TRectangle
        Align = Right
        Fill.Color = claBlue
        HitTest = False
        Position.X = 53.000000000000000000
        Size.Width = 50.000000000000000000
        Size.Height = 50.000000000000000000
        Size.PlatformDefault = False
        Stroke.Kind = None
        OnClick = Button1Click
        object Button1: TButton
          Align = Client
          Size.Width = 50.000000000000000000
          Size.Height = 50.000000000000000000
          Size.PlatformDefault = False
          StyleLookup = 'buttonstyle'
          TabOrder = 0
          TintColor = claBlue
          OnClick = Button1Click
        end
      end
      object Rectangle2: TRectangle
        Align = Right
        Fill.Color = claGreen
        HitTest = False
        Position.X = 103.000000000000000000
        Size.Width = 50.000000000000000000
        Size.Height = 50.000000000000000000
        Size.PlatformDefault = False
        Stroke.Kind = None
        OnClick = Button2Click
        object Button2: TButton
          Align = Client
          Size.Width = 50.000000000000000000
          Size.Height = 50.000000000000000000
          Size.PlatformDefault = False
          StyleLookup = 'buttonstyle'
          TabOrder = 0
          TintColor = claGreen
          OnClick = Button2Click
        end
      end
    end
  end
end