delphi – 在firemonkey移动开发中正确使用TAniIndicator等待处

发布时间：2020-12-15 09:43:12 所属栏目：大数据来源：网络整理

导读：我正在使用Delphi XE-5(Firemonkey移动应用程序) 我想通过在长时间处理期间显示来让TAniIndicator工作. 我的主表单上有一个TAniIndicator(AniIndi),但它没有旋转.它显示正确,但不旋转. begin Loading:= True; AniIndi.Visible:= True; AniIndi.Enabled:= Tru

我正在使用Delphi XE-5(Firemonkey移动应用程序)

我想通过在长时间处理期间显示来让TAniIndicator工作.
我的主表单上有一个TAniIndicator(AniIndi),但它没有旋转.它显示正确,但不旋转.

begin
 Loading:= True;
 AniIndi.Visible:= True;
 AniIndi.Enabled:= True;
 UpdateAll;
 Application.ProcessMessages;

 //do my processsing here

 Loading:= False;
 AniIndi.Enabled:= False;
 AniIndi.Visible:= False;
 UpdateAll;
 Application.ProcessMessages;
end;

//基于REMY的答案进行编辑

TLoadThread = class(TThread)
 public
  Config: Boolean;
  constructor Create(const aConfig: Boolean); reintroduce;
 protected
  procedure DoProcessing;
  procedure Execute; Override;
 end;

var
 loading: Boolean = false;
 zLThread: TLoadThread = nil;

constructor TLoadThread.Create(const aConfig: Boolean);
begin
 inherited Create(true);
 Config:= aConfig;
end;

procedure TLoadThread.DoProcessing;
var
begin
 //do processing here and update main form
end;

procedure TLoadThread.Execute;
begin
 FreeOnTerminate:= true;
 Synchronize(DoProcessing);
end;


procedure TfrmMain.FormActivate(Sender: TObject);
begin
 zLThread:= TLoadThread.Create(True,Host,NamePath,Config,Port);
 zLThread.OnTerminate := ThreadTerminated;
 zLThread.Start;
 Loading := True;
 AniIndi.Visible := True;
 AniIndi.Enabled := True;
 UpdateAll;
end;

procedure TfrmMain.ThreadTerminated(Sender: TObject);
begin
  zLThread := nil;
  Loading := False;
  AniIndi.Enabled := False;
  AniIndi.Visible := False;
  UpdateAll;
end;

解决方法

在长进程运行时,主线程需要对消息队列保持响应.如果没有,则阻止动画(以及UI的其他方面)接收新消息,例如绘制请求和计时器通知.您需要将任何长处理移动到单独的线程中.启动线程,然后启动动画.让主线程在此期间正常处理UI.线程完成后,让它通知主线程,然后主线程可以停止动画,并完成线程结果所需的任何其他处理(如果有的话).例如：

type
  TLoadThread = class(TThread)
  public
    Host: string;
    NamePath: string;
    Port: Integer;
    Config: Boolean;
    constructor Create(const aHost,aNamePath: string; aPort: Integer; aConfig: Boolean); reintroduce;
  protected
    procedure Execute; override;
  end;

constructor TLoadThread.Create(const aHost,aNamePath: string; aPort: Integer; aConfig: Boolean);
begin
  inherited Create(True);
  FreeOnTerminate := True;
  Host := aHost;
  NamePath := aNamePath;
  Port := aPort;
  Config := aConfig;
end;

procedure TLoadThread.Execute;
begin
  //do processing

  Synchronize(
    procedure
      //update main form
    end
  );

  //do processing
end;

var
  Loading: Boolean = False;
  zLThread: TLoadThread = nil;

procedure TfrmMain.FormActivate(Sender: TObject);
begin
  zLThread := TLoadThread.Create(Host,Port,Config);
  zLThread.OnTerminate := ThreadTerminated;
  zLThread.Start;
  Loading := True;
  AniIndi.Visible := True;
  AniIndi.Enabled := True;
  UpdateAll;
end;

procedure TfrmMain.ThreadTerminated(Sender: TObject);
begin
  zLThread := nil;
  Loading := False;
  AniIndi.Enabled := False;
  AniIndi.Visible := False;
  UpdateAll;
end;

（编辑：李大同）

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