ListView 下拉更新 (支持 Android)

//------------------------------------------------------------------------------
// 2013.12.30 by 龟山阿卍 QQ 1467948783                                        -
// http://www.cnblogs.com/onechen/                                             -
//                                                                             -
// 需修改                                                                      -
// FMX.Platform.Android.pas                                                    -
// function TPlatformAndroid.GetScrollingBehaviour: TScrollingBehaviours;      -
//------------------------------------------------------------------------------

unit Main;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.StdCtrls,
  FMX.ListView.Types, FMX.Objects, FMX.ListView, FMX.Ani;

type
  TForm1 = class(TForm)
    ToolBar1: TToolBar;
    ListView1: TListView;
    PullPaintBox: TPaintBox;
    AniIndicator1: TAniIndicator;
    RefreshTimer: TTimer;
    RefreshLabel: TLabel;
    RefreshImage: TImage;
    FloatAnimation1: TFloatAnimation;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure ListView1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Single);
    procedure ListView1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Single);
    procedure RefreshTimerTimer(Sender: TObject);
  private
    ShowUp, ShowDown: Boolean;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.FormCreate(Sender: TObject);
var i: Integer;
    Item1: TListViewItem;
begin
     for i:=0 to 100 do
     begin
          Item1 := ListView1.Items.Add;
          Item1.Text := i.ToString;
     end;
     ShowUp   := False;
     ShowDown := False;
end;

procedure TForm1.ListView1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Single);
begin
     if not AniIndicator1.Visible then
     begin
          RefreshLabel.Visible := True;
          if ListView1.ScrollViewPos < -80 then
          begin
               RefreshLabel.Text := '放开后可更新';

               RefreshImage.Visible := True;
               if not ShowUp then
               begin
                    ShowUp := True;
                    FloatAnimation1.StartValue := 360;
                    FloatAnimation1.StopValue  := 180;
                    FloatAnimation1.Start;
               end;
          end
          else
          if ListView1.ScrollViewPos < -40 then
          begin
               RefreshLabel.Text := '下拉可更新';

               RefreshImage.Visible := True;
               if not ShowDown then
               begin
                    ShowDown := True;
                    FloatAnimation1.StartValue := 180;
                    FloatAnimation1.StopValue  := 360;
                    FloatAnimation1.Start;
               end;
          end
          else
          begin
               RefreshLabel.Text := '';
               RefreshImage.Visible := False;
          end;
     end;
end;

procedure TForm1.ListView1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Single);
begin
     if RefreshLabel.Visible then
     begin
          RefreshLabel.Visible := False;

          // 开始更新
          AniIndicator1.Visible := True;
          AniIndicator1.Enabled := True;

          RefreshTimer.Enabled := True;
     end;
end;

procedure TForm1.RefreshTimerTimer(Sender: TObject);
begin
     // 结束更新
     RefreshTimer.Enabled  := False;

     AniIndicator1.Enabled := False;
     AniIndicator1.Visible := False;

     ShowUp   := False;
     ShowDown := False;
end;

end.