[范例] Firemonkey Edit 输入框只允许输入数字 for Android

// Android 平台不用下列方法
procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word; var KeyChar: Char; Shift: TShiftState);
begin
     if not (KeyChar in [‘0‘..‘9‘]) then
        KeyChar := #0;
end;

var NowEdit: Boolean;

procedure TForm1.Edit1ChangeTracking(Sender: TObject);
begin
     if NowEdit then Exit;

     if not (Edit1.Text.Chars[Edit1.Text.Length - 1] in [‘0‘..‘9‘]) then
     begin
          NowEdit := True;
          Edit1.Text := Edit1.Text.Substring(0, Edit1.Text.Length - 1);
          NowEdit := False;
     end;
end;