iOS：如何在日期选择器对话框中添加标题

Question

我想在日期选择器对话框中添加一个标题。这就是我创建日期选择器对话框的方式：

  // We should Create instance of UIDatePicker before creating main container.
  // Because We use UIViewPicker for determinate finally size of picker container
  // (Toolbar + Picker)
  FUIDatePicker := TUIDatePicker.Create;
  FUIDatePicker.setTimeZone(TNSTimeZone.Wrap(TNSTimeZone.OCClass.timeZoneForSecondsFromGMT(0)));
  FUIDatePicker.setDatePickerMode(UIDatePickerModeDate);

  { Subscribing to change orientation events }
  DefaultNotificationCenter.addObserver(GetObjectID, sel_getUid('DeviceOrientationChanged'), StringToID(FMXViewControllerFrameChanged), nil);

  { Creating Root view container for picker }
  FUIOverlayView := TUIView.Create;
  aUIColor := AlphaColorToUIColor($32000000);
  FUIOverlayView.setBackgroundColor(aUIColor);
  FUIOverlayView.setAutoresizingMask(UIViewAutoresizingFlexibleWidth or
                                     UIViewAutoresizingFlexibleHeight or
                                     UIViewAutoresizingFlexibleLeftMargin or
                                     UIViewAutoresizingFlexibleRightMargin or
                                     UIViewAutoresizingFlexibleTopMargin or
                                     UIViewAutoresizingFlexibleBottomMargin);
  FUIOverlayView.setFrame(CGRect.Create(0, 0, screen.Size.Width, screen.Size.Height));
  aSingleTapGestureRecognizer := TUITapGestureRecognizer.Wrap(TUITapGestureRecognizer.Alloc.initWithTarget(GetObjectID, sel_getUid('HandleTap')));
  aSingleTapGestureRecognizer.setDelegate(GetObjectID);
  aSingleTapGestureRecognizer.setNumberOfTapsRequired(1);
  try
    FUIOverlayView.addGestureRecognizer(aSingleTapGestureRecognizer);
  finally
    aSingleTapGestureRecognizer.release;
  end;

  { Creating Root view container for picker }
  FUIContainerView := TUIView.Create;
  FUIContainerView.setBackgroundColor(TUIColor.Wrap(TUIColor.OCClass.whiteColor));
  FUIContainerView.setAutoresizingMask(UIViewAutoresizingFlexibleWidth or
                                       UIViewAutoresizingFlexibleLeftMargin or
                                       UIViewAutoresizingFlexibleRightMargin);
  FUIContainerView.setFrame(GetPopupFrame);
  FUIContainerView.layer.setMasksToBounds(true);
  FUIContainerView.layer.setCornerRadius(12);

  { Creating Toolbar }
  FUIToolBar := TUIToolbar.Create;
  FUIToolBar.setAlpha(0.8);
  FUIContainerView.addSubview(FUIToolBar);
  CreateToolbarConstraint;

  { Creating Toolbar buttons }
  aButtons := TNSMutableArray.Create;
  try

    { Adding Flexible Separator }
    FUIFlexibleSepararator1 := TUIBarButtonItem.Create;
    FUIFlexibleSepararator1.initWithBarButtonSystemItem(UIBarButtonSystemItemFixedSpace, nil, nil);
    FUIFlexibleSepararator1.setWidth(5);
    aButtons.addObject(NSObjectToID(FUIFlexibleSepararator1));

    { Adding clear Button }
    if aBtnClearCaption <> '' then begin
      FUIClearButton := TUIBarButtonItem.Create;
      FUIClearButton.setTitle(StrToNSStr(aBtnClearCaption));
      FUIClearButton.setStyle(UIBarButtonItemStyleBordered);
      FUIClearButton.setTarget(Self.GetObjectID);
      FUIClearButton.setAction(sel_getUid('Clear'));
      aButtons.addObject(NSObjectToID(FUIClearButton));
    end
    else FUIClearButton := nil;

    { Adding Flexible Separator }
    FUIFlexibleSepararator2 := TUIBarButtonItem.Create;
    FUIFlexibleSepararator2.initWithBarButtonSystemItem(UIBarButtonSystemItemFlexibleSpace, nil, nil);
    aButtons.addObject(NSObjectToID(FUIFlexibleSepararator2));

    { Adding Close Button }
    if aBtnCancelCaption <> '' then begin
      FUICancelButton := TUIBarButtonItem.Create;
      FUICancelButton.setTitle(StrToNSStr(aBtnCancelCaption));
      FUICancelButton.setStyle(UIBarButtonItemStyleBordered);
      FUICancelButton.setTarget(Self.GetObjectID);
      FUICancelButton.setAction(sel_getUid('Cancel'));
      aButtons.addObject(NSObjectToID(FUICancelButton));
    end
    else FUICancelButton := nil;

    { Adding Flexible Separator }
    FUIFlexibleSepararator3 := TUIBarButtonItem.Create;
    FUIFlexibleSepararator3.initWithBarButtonSystemItem(UIBarButtonSystemItemFixedSpace, nil, nil);
    FUIFlexibleSepararator3.setWidth(28);
    aButtons.addObject(NSObjectToID(FUIFlexibleSepararator3));

    { Adding Done Button }
    FUIDoneButton := TUIBarButtonItem.Create;
    FUIDoneButton.setTitle(StrToNSStr(aBtnOKCaption));
    FUIDoneButton.setStyle(UIBarButtonItemStyleDone);
    FUIDoneButton.setTarget(Self.GetObjectID);
    FUIDoneButton.setAction(sel_getUid('Done'));
    aButtons.addObject(NSObjectToID(FUIDoneButton));

    { Adding Flexible Separator }
    FUIFlexibleSepararator4 := TUIBarButtonItem.Create;
    FUIFlexibleSepararator4.initWithBarButtonSystemItem(UIBarButtonSystemItemFixedSpace, nil, nil);
    if aBtnClearCaption <> '' then FUIFlexibleSepararator4.setWidth(5)
    else FUIFlexibleSepararator4.setWidth(15);
    aButtons.addObject(NSObjectToID(FUIFlexibleSepararator4));

    { Adding button to Toolbar }
    FUIToolBar.setItems(aButtons);

  finally
    aButtons.release;
  end;

  { Adding DatePicker }
  FUIContainerView.addSubview(FUIDatePicker);
  CreateCalendarConstraint;
  FUIOverlayView.addSubview(FUIContainerView);

和

  {~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~}
  procedure CreateToolbarConstraint;
  var Constraint: NSLayoutConstraint;
  begin
    FUIToolBar.setTranslatesAutoresizingMaskIntoConstraints(False);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIToolBar), NSLayoutAttributeLeft,   NSLayoutRelationEqual, NSObjectToID(FUIContainerView),    NSLayoutAttributeLeft,           1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIToolBar), NSLayoutAttributeRight,  NSLayoutRelationEqual, NSObjectToID(FUIContainerView),    NSLayoutAttributeRight,          1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIToolBar), NSLayoutAttributeBottom, NSLayoutRelationEqual, NSObjectToID(FUIContainerView),    NSLayoutAttributeBottom,         1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIToolBar), NSLayoutAttributeHeight, NSLayoutRelationEqual, nil,                               NSLayoutAttributeNotAnAttribute, 1, _ToolBarHeight));
    Constraint.setActive(True);
  end;

  {~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~}
  procedure CreateCalendarConstraint;
  var Constraint: NSLayoutConstraint;
  begin
    FUIDatePicker.setTranslatesAutoresizingMaskIntoConstraints(False);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIDatePicker), NSLayoutAttributeLeft,   NSLayoutRelationEqual, NSObjectToID(FUIContainerView), NSLayoutAttributeLeft,           1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIDatePicker), NSLayoutAttributeRight,  NSLayoutRelationEqual, NSObjectToID(FUIContainerView), NSLayoutAttributeRight,          1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIDatePicker), NSLayoutAttributebottom, NSLayoutRelationEqual, NSObjectToID(FUIToolBar),       NSLayoutAttributetop,            1, 0));
    Constraint.setActive(True);
    Constraint := TNSLayoutConstraint.Wrap(TNSLayoutConstraint.OCClass.constraintWithItem(NSObjectToID(FUIDatePicker), NSLayoutAttributeHeight, NSLayoutRelationEqual, nil,                            NSLayoutAttributeNotAnAttribute, 1, _DefaultPickerHeight));
    Constraint.setActive(True);
  end;

您知道我需要在此代码中进行哪些更改才能添加标题吗？