uses FMX.Objects;

procedure TForm1.Button1Click(Sender: TObject);
begin
  (Self.Children[0] as TRectangle).Fill.Color := claRed; //默认情况下, 通过 Children[0] 可读出这个矩形, 但其次序(Index)是可变的
  ShowMessage(Children[0].ToString); //TRectangle

  {Panel1 上也是盖着一个矩形对象, 应该还有其它也是这样}
  TRectangle(Panel1.Children[0]).Fill.Color := claYellow;
end;

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs;

type
  TForm1 = class(TForm)
  private
  public
    { 在 TForm1 声明区 -> Ctrl+空格 -> 输入 MouseM... -> 回车 -> Shift+Ctrl+C }
    procedure MouseMove(Shift: TShiftState; X: Single; Y: Single); override;
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.MouseMove(Shift: TShiftState; X, Y: Single);
begin
  inherited;
  Caption := Format('%f, %f', [X, Y]);
end;

end.

{ TCommonCustomForm }
public
  constructor Create(...); override;   //
  constructor CreateNew(...); virtual; //它比 Create() 多出一个默认参数 Dummy, 但没看出什么用途(可能是给3D窗口用的吧); 暂时它和 Create() 没什么区别
  destructor Destroy; override;        //
  procedure InitializeNewForm; virtual;   //窗体初始化, 可通过覆盖此方法初始化窗体属性
  procedure AfterConstruction; override;  //建立后
  procedure BeforeDestruction; override;  //销毁前
  procedure AddObject(...); override;     //添加对象
  { children }
  function ObjectAtPoint(...): IControl; virtual; //指定位置上的控件
  { called from Platform }
  procedure SetMarkedText(...); virtual; //使用输入法时, 确认输入前的文本; 覆盖此方法可截获
  procedure PaintRects(...); virtual;    //更新指定的矩形(数组)范围; TCustomForm 里才有它的实现代码
  procedure MouseDown(...); virtual;          //响应鼠标事件
  procedure MouseMove(...); virtual;          //...
  procedure MouseUp(...); virtual;            //...
  procedure MouseWheel(...); virtual;         //...
  procedure MouseLeave; virtual;              //...
  procedure KeyDown(...); virtual;            //响应键盘事件
  procedure KeyUp(...); virtual;              //...
  function GetImeWindowRect: TRectF; virtual; //获取拥有输入焦点对象的范围矩形
  procedure Activate;                   //激活
  procedure Deactivate;                 //取消激活
  procedure DragEnter(...); virtual;    //响应拖放事件
  procedure DragOver(...); virtual;     //...
  procedure DragDrop(...); virtual;     //...
  procedure DragLeave; virtual;         //...
  procedure EnterMenuLoop;              //调用 TMenuBar 对象的 StartMenuLoop 方法
  { settings }
  procedure SetBounds(...); virtual;      //设置位置与大小
  function ClientToScreen(...): TPointF;  //点转换
  function ScreenToClient(...): TPointF;  //...
  function CloseQuery: Boolean; virtual;  //触发 OnCloseQuery 事件
  function ClientRect: TRectF;            //客户区矩形
  procedure Release;                      //释放
  procedure Close;                        //关闭
  procedure Show;                         //显示
  procedure Hide;                         //隐藏
  function ShowModal: TModalResult;       //显示为模态窗口
  procedure CloseModal;                   //触发 OnCloseQuery、OnClose 事件
  procedure Invalidate;                   //使无效而强制刷新
  procedure BeginUpdate;                  //开始更新
  procedure EndUpdate;                    //结束更新
  property Handle: TFmxHandle ...;        //窗口句柄
  property ContextHandle: THandle ...;    //环境句柄
  property ModalResult: TModalResult ...; //模态窗口的返回值
  property FormState: TFmxFormStates ...; //窗口模式状态
  property Designer: IDesignerHook ...;   //设计时相关的接口
  { IRoot }
  property Captured: IControl ...;  //被鼠标选中的控件
  property Focused: IControl ...;   //拥有焦点的控件
  property Hovered: IControl ...;   //鼠标下的控件
  property IsActive: Boolean ...;   //是否是激活状态
  property BiDiMode: TBiDiMode ...; //不同语言的方向
  property Caption: string ...;     //标题
  property Cursor: TCursor ...;     //光标类型
  property BorderStyle: TFmxFormBorderStyle ...; //边框样式
  property BorderIcons: TBorderIcons ...;        //工具条上的按钮
  property ClientHeight: Integer ...;            //客户区高
  property ClientWidth: Integer ...;             //客户区宽
  property Margins: TBound ...;                  //内边距
  property Position: TFormPosition ...;          //相对位置
  property Width: Integer ...;                   //宽
  property Height: Integer ...;                  //高
  property ShowActivated: Boolean ...;           //打开时是否激活
  property StaysOpen: Boolean ...;               //是否延迟打开
  property Transparency: Boolean ...;            //能否透明
  property TopMost: Boolean ...;                 //是否在最顶层
  property Visible: Boolean ...;                 //是否隐藏
  property WindowState: TWindowState ...;        //窗口状态(常态、最大化、最小化)
  property OnCreate: TNotifyEvent ...;          //建立时
  property OnDestroy: TNotifyEvent ...;         //销毁时
  property OnClose: TCloseEvent ...;            //关闭时
  property OnCloseQuery: TCloseQueryEvent ...;  //将要关闭时
  property OnActivate: TNotifyEvent ...;        //被激活时
  property OnDeactivate: TNotifyEvent ...;      //丢激活时
  property OnResize: TNotifyEvent ...;          //调整大小时
published
  property Left: Integer ...; //左
  property Top: Integer ...;  //上
end;


{ TCustomForm }
public
  constructor Create(...); override;    //
  constructor CreateNew(...); override; //
  destructor Destroy; override;               //释放
  procedure InitializeNewForm; override;      //初始化 Form, 应该是内部自动调用的
  procedure AddObject(...); override;         //添加对象
  procedure UpdateStyle;                      //更新样式
  property Canvas: TCanvas ...;               //绘图层
  property Fill: TBrush ...;                  //画刷
  property StyleBook: TStyleBook ...;         //样式表
  property ActiveControl: TStyledControl ...; //激活控件或获取被激活的控件
  property StyleLookup: string ...;           //指定控件样式名
  property OnPaint: TOnPaintEvent ...;        //重绘时
end;