Android实例-TTabControl的使用(XE8+小米2)

结果： 

1.如果直接改变Tab的TabIndex，那样是没有动态效果的。如果想要动态效果需要用到ChangeTabAction1;

2.ChangeTabAction1可以直接为按钮指定Action这样不写代码，也可以支持动态效果。

3.ExecuteTarget是执行跳转功能，查看源代码，没有找到参数是做什么的。所以真心不明白里面的参数是什么意思。希望哪位前辈指点。

4.有人可能感觉出来了，为什么Android上的QQ、微信什么的手势都那么好用，而Delphi的有时不好使。其实不是这样的。那是因为Delphi中是直线向左、向右才识别。有关手势的我会重写文章说明，此文只是对Tab控件的功能介绍。

实例代码：

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  FMX.Controls.Presentation, FMX.StdCtrls, FMX.ListBox, FMX.Layouts,
  FMX.TabControl, System.Actions, FMX.ActnList, FMX.NumberBox, FMX.Edit,
  FMX.EditBox, FMX.SpinBox, FMX.Gestures;

type
  TForm1 = class(TForm)
    TabControl1: TTabControl;
    Layout1: TLayout;
    ComboBox1: TComboBox;
    Label1: TLabel;
    TabItem1: TTabItem;
    TabItem2: TTabItem;
    TabItem3: TTabItem;
    TabItem4: TTabItem;
    Button1: TButton;
    Button2: TButton;
    ActionList1: TActionList;
    ChangeTabAction1: TChangeTabAction; //手动增加的Action
    ChangeTabAction2: TChangeTabAction; //手动增加的Action
    ChangeTabAction3: TChangeTabAction; //手动增加的Action
    ChangeTabAction4: TChangeTabAction; //手动增加的Action
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Button6: TButton;
    Button7: TButton;
    Button8: TButton;
    Button11: TButton;
    Button12: TButton;
    GestureManager1: TGestureManager; //手动增加的控件
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button7Click(Sender: TObject);
    procedure Button8Click(Sender: TObject);
    procedure Button11Click(Sender: TObject);
    procedure Button12Click(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure TabControl1Gesture(Sender: TObject;
      const EventInfo: TGestureEventInfo; var Handled: Boolean);
    procedure FormKeyUp(Sender: TObject; var Key: Word; var KeyChar: Char;
      Shift: TShiftState);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}
{$R *.NmXhdpiPh.fmx ANDROID}

//为了实现手势必须做的设置
procedure TForm1.FormCreate(Sender: TObject);
begin
  //为Tab指定一个手势控件
  TabControl1.Touch.GestureManager := GestureManager1;
  //设置Tab控件支持的手势有哪些(如果这一项不设置，手势是没有反映的)
  TabControl1.Touch.StandardGestures := [TStandardGesture.sgLeft, TStandardGesture.sgRight];
end;

//Action上一页
procedure TForm1.Button11Click(Sender: TObject);
begin
  if TabControl1.TabIndex > 0 then
  begin
    ChangeTabAction1.Tab := TTabItem(Form1.FindComponent('TabItem' + IntToStr(TabControl1.TabIndex)));
    ChangeTabAction1.ExecuteTarget(Self);
  end;
end;

//Action下一页
procedure TForm1.Button12Click(Sender: TObject);
begin
  if TabControl1.TabIndex < TabControl1.TabCount - 1 then
  begin
    ChangeTabAction1.Tab := TTabItem(Form1.FindComponent('TabItem' + IntToStr(TabControl1.TabIndex + 2)));
    ChangeTabAction1.ExecuteTarget(Self);
  end;
end;

//Tab上一页
procedure TForm1.Button1Click(Sender: TObject);
begin
  if TabControl1.TabIndex > 0 then
  begin
    TabControl1.TabIndex := TabControl1.TabIndex - 1;
  end;
end;

//Tab下一页
procedure TForm1.Button2Click(Sender: TObject);
begin
  if TabControl1.TabIndex < TabControl1.TabCount - 1 then
  begin
    TabControl1.TabIndex := TabControl1.TabIndex + 1;
  end;
end;

//ExecuteTarget方法1
procedure TForm1.Button7Click(Sender: TObject);
begin
  ChangeTabAction1.ExecuteTarget(self);
end;

//ExecuteTarget方法2
procedure TForm1.Button8Click(Sender: TObject);
begin
  ChangeTabAction1.ExecuteTarget(TabControl1);
end;

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
  case ComboBox1.ItemIndex of
    0: TabControl1.TabPosition := TTabPosition.PlatformDefault;
    1: TabControl1.TabPosition := TTabPosition.Top;
    2: TabControl1.TabPosition := TTabPosition.Bottom;
    3: TabControl1.TabPosition := TTabPosition.None;
    4: TabControl1.TabPosition := TTabPosition.Dots;
  end;
end;

//利用手机的返回键实现Tab跳转
procedure TForm1.FormKeyUp(Sender: TObject; var Key: Word; var KeyChar: Char;
  Shift: TShiftState);
begin
  if Key = vkHardwareBack then
  begin
    if TabControl1.TabIndex > 0 then
    begin
      TabControl1.TabIndex := TabControl1.TabIndex - 1 mod TabControl1.TabCount;
      Key := 0;
    end;
  end;
end;

//利用手势实现Tab跳转
procedure TForm1.TabControl1Gesture(Sender: TObject;
  const EventInfo: TGestureEventInfo; var Handled: Boolean);
begin
  case EventInfo.GestureID of
    sgiLeft:
    begin
      case TabControl1.TabIndex of
        0: ChangeTabAction2.ExecuteTarget(self);
        1: ChangeTabAction3.ExecuteTarget(self);
        2: ChangeTabAction4.ExecuteTarget(self);
      end;
    end;
    sgiRight:
    begin
      case TabControl1.TabIndex of
        3: ChangeTabAction3.ExecuteTarget(self);
        2: ChangeTabAction2.ExecuteTarget(self);
        1: ChangeTabAction1.ExecuteTarget(self);
      end;
    end;
  end;
  Handled := True;
end;

end.