省去全局变量记忆光标位置

Unit1.LgXhdpiPh.fmx

@@ -20,7 +20,6 @@ inherited Form1_LgXhdpiPh: TForm1_LgXhdpiPh
     Size.Height = 695.000000000000000000
     inherited Memo1: TMemo
       Size.Width = 433.000000000000000000
-      OnExit = Memo1Exit
       Viewport.Width = 433.000000000000000000
       Viewport.Height = 473.000000000000000000
     end

Unit1.pas

@@ -29,18 +29,13 @@ type
     procedure FormClose(Sender: TObject; var Action: TCloseAction);
     procedure Memo1MouseLeave(Sender: TObject);
     procedure Button1Click(Sender: TObject);
-    procedure Memo1Exit(Sender: TObject);
-
 
 
   private
     { Private declarations }
 
-
-
     procedure ToastConfirm(const AStr: string);
     procedure AniToastFinish(Ani: TObject);
-
     procedure SetFileName(const FileName: String);
     procedure PerformFileOpen(const AFileName: string);
     procedure ResultProc(AResult: Boolean; AFileName: string);   //打开参数过程
@@ -67,8 +62,7 @@ uses
   MyDialogs;
 type
   TTextFormat=(tfAnsi, tfUnicode, tfUnicodeBigEndian, tfUtf8);
-var
-  MemoLastPos:integer;  //光标最后位置
+
 const
   //TextFormatFlag: array[tfAnsi..tfUtf8] of word=($0000,$FFFE,$FEFF,$EFBB);
   TextFormatFlag: array[tfAnsi..tfUtf8] of word=($0000,$FEFF,$FFFE,$BBEF); //编码标志高低字节互换
@@ -85,7 +79,6 @@ resourcestring
   sCommonDlgFileName = '文本文档(*.txt)|*.txt|所有文件(*.*)|*.*';
 
 
-
 procedure TForm1.SetFileName(const FileName: String);
 begin
   FFileName := System.IOUtils.Tpath.GetSharedDocumentsPath+'/'+FileName+'.txt';
@@ -197,7 +190,7 @@ begin
    with Memo1 do
    begin
      Line := CaretPosition.line ;
-     SelStart := MemoLastPos-CaretPosition.pos ;
+     SelStart := SelStart - CaretPosition.pos ;
      if lines.count>0 then SelLength := Length(Lines[Line]) ;  //如不是空文件，选当前行
    end;
 end;
@@ -231,15 +224,11 @@ begin
   SetFileName(sUntitled);
   label1.text:='当前文件：'+sUntitled+'.txt';
   memo1.height:= 473;  //将meno控件恢复到默认高度
-  MemoLastPos:=0; //光标位置变量初始化
 
 end;
 
 
-procedure TForm1.Memo1Exit(Sender: TObject);
-begin
-   MemoLastPos:= memo1.SelStart;  //memo1失去焦点前记住当前光标位置
-end;
+
 
 procedure TForm1.Memo1MouseLeave(Sender: TObject);     //改变memo1高度以适应虚拟键盘
 var