어플의 상태변화 이벤트 받아오기

uses
  .., FMX.Platform;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    function AppEventHandler(AppEvent: TApplicationEvent; AContext: TObject): Boolean;
  end;

FormCreate에서 어플의 이벤트서비스에 이벤트핸들러를 추가합니다.

procedure TForm1.FormCreate(Sender: TObject);
var
  AppEventService: IFMXApplicationEventService;
begin
  if TPlatformServices.Current.SupportsPlatformService(IFMXApplicationEventService, IInterface(AppEventService)) then
  begin
    AppEventService.SetApplicationEventHandler(AppEventHandler);
  end;
end;

function TForm1.AppEventHandler(AppEvent: TApplicationEvent;
  AContext: TObject): Boolean;
begin
  with TApplicationEvent do
  begin
    case AppEvent of //받아온 이벤트에 따라 처리합니다.
      FinishedLaunching: {To Do};
      BecameActive:  {To Do};
      WillBecomeInactive: {To Do};
      EnteredBackground: {To Do};
      WillBecomeForeground: {To Do};
      WillTerminate: {To Do};
      LowMemory: {To Do};
      TimeChange: {To Do};
      OpenURL: {To Do};
    end;
  end;

  Result := True;
end;

Description

Type of an application event.

An instance of TApplicationEvent may have any of the following values:

Item	Description	Platform
		Android	iOS
BecameActive	Your application has gained the focus.	Supported	Supported
EnteredBackground	The user is no longer using your application, but your application is still running in the background.	Supported	Supported
FinishedLaunching	Your application has been launched.	Supported	Supported
LowMemory	This warns your application that the device is running out of memory. Your application should reduce memory usage, freeing structures and data that can be loaded again at a later point.	Supported	Supported
OpenURL	You application has received a request to open an URL. Application events of this type are usually associated with a context. This context is an instance of the iOS-only TiOSOpenApplicationContext class, which provides the following read-only properties: TiOSOpenApplicationContext.SourceApp is a string that contains the bundle ID of the application that requested your application to open the URL. TiOSOpenApplicationContext.URL is the URL to open, either a network resource or a file. TiOSOpenApplicationContext.Context is a pointer to a property-list object that might provide additional information. See the iOS API reference documentation for more information.		Supported
TimeChange	There has been a significant change in time. This event might happen for example when the day changes or when the device changes to or from daylight savings time.		Supported
WillBecomeForeground	The user is now using your application, which was previously in the background.	Supported	Supported
WillBecomeInactive	Your application is going to loose the focus.	Supported	Supported
WillTerminate	The user is quitting your application.	Supported	Supported

참조 : http://docwiki.embarcadero.com/Libraries/XE8/en/FMX.Platform.TApplicationEvent