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[英]TGIFImage with animated GIF - events are not working - how to detect animation progress?
[英]Animation of a Gif image is not working when execute a process
我有一个 Delphi 项目,它由两种形式组成,即MainForm和DialogForm 。 当我单击Button1 时, DialogForm应该出现并保持在顶部,直到一个过程完成(该过程需要几秒钟才能完成)。
DialogForm包括一个Timage组件。 当我单击Button1以显示DialogForm 时,Gif 图像出现但没有动画。 这仅在进程开始时发生(没有动画工作的进程)。 这是什么原因以及如何在关闭DialogForm之前保持动画?
procedure TMainForm.Button1Click(Sender: TObject);
var
gif: TGIFImage;
begin
Enabled:=false;
try
DialogForm.Show;
DialogForm.Refresh;
// The process is:
...
ipcAES1.Encrypt;//where ipcAES is part of the IPWorks Encrypt library
RichEdit1.Text:=ipcAES1.OutputMessage;
finally
Enabled:= true;
DialogForm.Close;
end;
end;
//---------------------------------------
procedure TDialogForm.FormShow(Sender: TObject);
var
gif: TGIFImage;
begin
gif := TGIFImage.Create;
gif.LoadFromFile('D:\preview.gif');
gif.Animate := True;
image1.Parent := Self;
image1.Left := 0;
image1.Top := 0;
image1.width := 800;
image1.height := 800;
image1.Picture.Assign(gif);
gif.Animate := True;
gif.Free;
end;
正如这个线程中的许多人所说,因为处理是在主线程中完成的,因此在此过程中不会更新UI。
为了确保在进程运行时更新 UI,让一个单独的线程进行处理:
procedure TForm1.Button1Click(Sender: TObject);
var
aProcessingThread: TThread;
begin
// First read all data needed by the process from UI controls (or other non-threadsafe parts)
<data> := ...;
// Then create a new (anonymous) thread with the code you need to run your process
aProcessingThread := TThread.CreateAnonymousThread(
procedure
begin
// create the objects you need to do the processing
ipcAES1 := Txxx.Create;
try
// Set the data
ipcAES1.<data> := <data>;
// Execute the proces:
// ...
ipcAES1.Encrypt;
finally
// When the process is done, use 'Synchronize' to interact with the UI
// again, so you can add the processed data to the RichtEdit and so on...
TThread.Synchronize(nil,
procedure
begin
// Now you can interact again with the UI
RichEdit1.Text := ipcAES1.OutputMessage;
Enabled:= true;
DialogForm.Close;
end);
ipcAES1.Free;
end;
end);
// The thread is now created, but not started/running, so you can now show
// the dialog and then start the thread, at which point the ButtonClick event
// exists, but the progress dialog is shown and the thread is running.
Enabled := False;
DialogForm.Show;
aProcessingThread.Start;
end;
当然,这只是如何使用(匿名)线程在后台进行一些处理的基本示例。 请注意,您需要在线程内处理异常(尝试/除外)。
关于 TGifImage 加载的一个小技巧:只要在 uses 子句中包含Vcl.Imaging.GIFImg
,您就可以调用Picture.LoadfromFile
来加载 gif。
procedure TForm1.FormShow(Sender: TObject);
begin
image1.Picture.LoadFromFile('D:\preview.gif');
image1.Parent := Self;
image1.Left := 0;
image1.Top := 0;
image1.width := Image1.Picture.Width;
image1.height := Image1.Picture.Height;
(image1.Picture.Graphic as TGIFImage).Animate := True;
end;
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