Question

我有一个具有多个表单的应用程序，每个表单都有一个线程，每隔3秒对给定的URL执行一次GET（）...问题是每次调用GET（）用户界面都会冻结直到GET （）完成后，各种表单如何每3秒做一次同样的事情，应用程序很慢，在主窗体上放了一个“IdAntiFreeze”，大多数都没用，所以读“IdAntiFreeze”不起作用线程，遵循以下示例：

  private
    { Private declarations }
    GlobalHtml : String;
    TimerGlobal : Integer;

//螺纹

TMyThread= class(TThread)
private
  FForm : TForm1;
  strTemp: String;
protected
  procedure Execute; override;
public
  constructor Create(Form : TForm1; gpLinkTemp : String);
  destructor Destroy; override;
end;

//获取字符串http

procedure TMyThread.GetStringHttp;
var
  meuIdHTTP : TIdHttp;
  strResponse:  String;
begin
  meuIdHTTP := TIdHTTP.Create(nil);
  strResponse := meuIdHTTP.Get('url...'); //<-- freezes up complete
  FForm.GlobalHtml := strResponse; //<-- private form variable
end;

//执行

procedure TMyThread.Execute;
begin
  while not (terminated) do
   begin 
      Synchronize(GetStringHttp);
      FForm.LabelStatus.Visible := False;
      FForm.ButtonStatus.Enabled := False;
      FForm.TimerStatus.Enabled := True;
      if FForm.TimerGlobal >= 10 then
       begin
         Synchronize(UpdateGrid);
         FForm.TimerGlobal := 0;
       end;
   end;
end;

//在表单

上更新TStringGrid

procedure TForm1.UpdateGrid;
begin
 //I update the TStringGrid here with the data of variable
 TSGridDados.Cells[0,1] := GlobalHtml;
 //...
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
 Inc(TimerGlobal);
end;

致电线程：

procedure TForm1.Button1Click(Sender: TObject);
begin
  TMyThread.Create(Self, 'string-url');
end;

如果互联网速度慢或者服务器响应更差， TIdHttp组件中是否有任何特殊配置可以避免这种情况？为什么会这样？提前谢谢！

Answer 1

以下是在线程中使用TIDHttp的示例您可以使用TList或TThreadList的多个线程，而不是下面提供的一个线程主要思想是使用＆＃34;线程安全＆＃34; waitinglist和resultlist的列表。
waitinglist用于列出每个网址请求，resultlist用于列出idhttp.get()的回复。

表单上的

Timer用于从resultlist弹出每个项目以进行GUI更新。

这是代码：
.dfm：

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 396
  ClientWidth = 660
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCloseQuery = FormCloseQuery
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  PixelsPerInch = 96
  TextHeight = 13
  object Splitter1: TSplitter
    Left = 193
    Top = 33
    Height = 363
    ExplicitLeft = 256
    ExplicitTop = 248
    ExplicitHeight = 100
  end
  object TreeView1: TTreeView
    Left = 0
    Top = 33
    Width = 193
    Height = 363
    Align = alLeft
    Indent = 19
    ReadOnly = True
    TabOrder = 0
    OnChange = TreeView1Change
    OnDeletion = TreeView1Deletion
  end
  object Memo1: TMemo
    Left = 196
    Top = 33
    Width = 464
    Height = 363
    Align = alClient
    Lines.Strings = (
      'Memo1')
    ScrollBars = ssBoth
    TabOrder = 1
    WordWrap = False
  end
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 660
    Height = 33
    Align = alTop
    BevelOuter = bvNone
    TabOrder = 2
    object Button1: TButton
      Left = 5
      Top = 5
      Width = 75
      Height = 25
      Caption = 'get URL'
      TabOrder = 0
      OnClick = Button1Click
    end
  end
  object IdAntiFreeze1: TIdAntiFreeze
    Left = 56
    Top = 64
  end
  object Timer1: TTimer
    Interval = 33
    OnTimer = Timer1Timer
    Left = 56
    Top = 120
  end
end

.pas：

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,
  Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, IdBaseComponent, IdAntiFreezeBase,
  Vcl.IdAntiFreeze, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP,
  Vcl.ComCtrls, Vcl.ExtCtrls, Vcl.StdCtrls, IdThreadSafe;

type

  TMyUrl = class(TStringlist)
  private
    fUrl:String;
  end;

  TMyThread= class(TThread)
  private
    fWaitingList : TIdThreadSafeObjectList;
    fResultList  : TIdThreadSafeObjectList;
  protected
    procedure Execute; override;
  public
    constructor Create(aWaitingList, aResultList:TIdThreadSafeObjectList);
  end;

  TForm1 = class(TForm)
    IdAntiFreeze1: TIdAntiFreeze;
    TreeView1: TTreeView;
    Memo1: TMemo;
    Splitter1: TSplitter;
    Timer1: TTimer;
    Panel1: TPanel;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure TreeView1Deletion(Sender: TObject; Node: TTreeNode);
    procedure Timer1Timer(Sender: TObject);
    procedure TreeView1Change(Sender: TObject; Node: TTreeNode);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    fWaitingList : TIdThreadSafeObjectList;
    fResultList  : TIdThreadSafeObjectList;
    fThread      : TmyThread;  //... You can change this to Multiple Threads instead
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{TMyThread}
constructor TMyThread.Create(aWaitingList, aResultList:TIdThreadSafeObjectList);
begin
  inherited Create;
  fWaitingList:=aWaitingList;
  fResultList:=aResultList;
end;

procedure TMyThread.Execute;
var
  Url:TMyUrl;
  http:TIdHttp;
begin
  while not Terminated do begin
    url:=fWaitingList.Pop;
    if assigned(url) then begin
      http:=TIdHTTP.Create(nil);
      try
        try
          url.Text:=http.Get(Url.fUrl);
        except
          on E:exception do
            Url.Text:=E.Message;
        end;
      finally
        http.Free;
        fResultList.Add(Url);
      end;
    end else
      sleep(100);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  MyUrl:TMyUrl;
  url:String;
begin
  url:='http://';
  if InputQuery('Add Url','Set Url',url) then begin
    url:=trim(url);
    if (sametext(copy(url,1,7),'http://')) and (length(url)>7) then begin
       MyUrl:=TMyUrl.Create;
       MyUrl.fUrl:=url;
       fWaitingList.Add(MyUrl);
    end;
  end;
end;

procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
  fThread.Terminate;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  fWaitingList:=TIdThreadSafeObjectList.Create;
  fResultList:=TIdThreadSafeObjectList.Create;
  fWaitingList.OwnsObjects:=true;
  fResultList.OwnsObjects:=true;
  fThread:=TMyThread.Create(fWaitingList, fResultList);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FreeAndNil(fWaitingList);
  FreeAndNil(fResultList);
  FreeAndNil(fThread);
end;

//.... For updating GUI every 33 miliseconds
procedure TForm1.Timer1Timer(Sender: TObject);
var
  url:TMyUrl;
begin
  url:=fResultList.Pop;
  if assigned(url) then begin
    with TreeView1.Items.AddChild(nil,url.fUrl) do
      data:=url;
  end;
end;

procedure TForm1.TreeView1Change(Sender: TObject; Node: TTreeNode);
begin
  if TreeView1.Selected<>nil then
    Memo1.Text:=TMyUrl(TreeView1.Selected.Data).Text;
end;

procedure TForm1.TreeView1Deletion(Sender: TObject; Node: TTreeNode);
begin
  TObject(Node.Data).Free;
  Node.Data:=nil;
end;

end.

希望这个小例子可以为你的作品提供一些灵感。

Delphi TIdHttp冻结线程

1 个答案: