Delphi XE2 之 FireMonkey 入门(33) - 控件基础: TFmxObject: SaveToStream、LoadFromStream、SaveToBinStream、LoadFromBinStream

Delphi XE2 之 FireMonkey 入门(33) - 控件基础: TFmxObject: SaveToStream、LoadFromStream、SaveToBinStream、LoadFromBinStream

SaveToStream()、LoadFromStream() 对应文本流;
SaveToBinStream()、LoadFromBinStream() 对应二进制流; 相对文本流, 二进制流会小一些.

有这几个方法, 控件数据与状态的序列化就太容易了.

示例:
1、控件: ListBox1、Button1、Button2
2、事件: Button1.OnClick、Button2.OnClick、Form1.OnCreate

unit Unit1;

interface

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

type
TForm1 = class(TForm)
ListBox1: TListBox;
Button1: TButton;
Button2: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.fmx}

{给 ListBox1 加点内容}
procedure TForm1.FormCreate(Sender: TObject);
var
i: Integer;
begin
for i := 0 to 9 do
ListBox1.Items.Add('Item' + IntToStr(i));
end;

{存取 ListBox1}
procedure TForm1.Button1Click(Sender: TObject);
const
path = 'c:\temp\ListBox1Stream.txt';
var
stream: TFileStream;
begin
{1}
stream := TFileStream.Create(path, fmCreate);
ListBox1.SaveToStream(stream);
stream.Free;

{2}
ListBox1.Clear;
ShowMessage('a');

{3}
stream := TFileStream.Create(path, fmOpenRead);
ListBox1.LoadFromStream(stream);
stream.Free;
end;

{存取当前窗体}
procedure TForm1.Button2Click(Sender: TObject);
const
path = 'c:\temp\Form1Stream.dat';
var
stream: TFileStream;
begin
{1}
stream := TFileStream.Create('c:\temp\Form1Stream.dat', fmCreate);
Self.SaveToBinStream(stream);
stream.Free;

{2}
Button1.Free;
Button2.Free;
ListBox1.Free;
Realign;
ShowMessage('a');

{3}
stream := TFileStream.Create('c:\temp\Form1Stream.dat', fmOpenRead);
Self.LoadFromBinStream(stream);
stream.Free;
end;

end.

状态保存测试:
1、控件: Button1、Button2、Panel1; 在 Panel1 中再放三个 TCheckBox
2、事件: Button1.OnClick、Button2.OnClick、Form1.OnCreate、Form1.OnDestroy

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)
Panel1: TPanel;
CheckBox1: TCheckBox;
CheckBox2: TCheckBox;
CheckBox3: TCheckBox;
Button1: TButton;
Button2: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.fmx}

var
stream: TMemoryStream;

procedure TForm1.FormCreate(Sender: TObject);
begin
stream := TMemoryStream.Create;
Button2.Enabled := False;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
stream.Free;
end;

{调整三个 CheckBox 的状态后保存}
procedure TForm1.Button1Click(Sender: TObject);
begin
Panel1.SaveToStream(stream);
ShowMessage(IntToStr(stream.Size));
Button2.Enabled := True;
end;

{恢复}
procedure TForm1.Button2Click(Sender: TObject);
begin
stream.Position := 0;
Panel1.LoadFromStream(stream);
end;

end.