如何显示进度条？ [英] how to display progress bar?

问题描述

我创建了一个隐写（隐藏位图中的文本）应用程序，我想添加一个进度条来显示该过程的工作时间。

I created a steganography(hide text in bitmap) application and I want to add a progress bar to show how long the process works.

procedure TForm1.Button2Click(Sender: TObject);
var
   x,y,i,currentBit,bitInChar,currentChar,currentPixel,newPixelValue,pixelsToSkip,skippedPixels: integer;
   pixels: PByteArray;
   bmp: TBitmap;
   stringToHide: string;
begin
if Image1.Picture.Bitmap=nil then
showmessage('gambar belum dipilih')
else
   memo1.lines.clear;
   stringToHide := AntiKeyLoggerMemo1.text;

   stringToHide:= stringToHide + chr(terminator); // add terminator to indicate end of text
   Image2.Picture.Assign(Image1.Picture.Bitmap);
   bmp := Image2.Picture.Bitmap;
   x := 0;
   y := 0;
   pixels := bmp.ScanLine[y];

   // iterate over the chars in the string we want to hide
   for i := 1 to length(stringToHide) do
   begin
      currentChar := ord(stringToHide[i]);
      memo1.lines.append('');
      memo1.lines.append('Sembunyikan ' + stringToHide[i] + ' - Ascii ' + inttostr(currentChar) + ' (biner ' + toBinary(currentChar) + ')');
      // iterate over the bits in the current char
      for currentBit := 7 downto 0 do
      begin
         begin
            if (i = 1) and (currentBit = 7) then
               pixelsToSkip := 0
            else
               pixelsToSkip := 1;
         end;
         for skippedPixels := 1 to pixelsToSkip do
         begin
            inc(x);
            if x = bmp.width then
            begin
               x := 0;
               inc(y);
               if (y = bmp.height) and (i < length(stringToHide)) then raise Exception.create('gambar terlalu kecil');
               pixels := bmp.ScanLine[y];
            end;
         end;
         bitInChar := getBit(currentChar, currentBit);
         // get the value of the pixel at x,y
         currentPixel := pixels[x];
         // set the least significant bit of the pixel to the bit we read from the char
         newPixelValue := setBit(currentPixel, 0, bitInChar);
         pixels[x] := newPixelValue;
         memo1.lines.append('Bit karakter ' + inttostr(currentBit) + '=' + inttostr(bitInChar) +
            ', pixel ke ' + inttostr(x) + ',' + inttostr(y) + ' desimal ' + inttostr(currentPixel) + ' (biner ' + toBinary(currentPixel) + ') ' +
            ' desimal baru ' + inttostr(newPixelValue) + ' (biner ' + toBinary(newPixelValue) + ')');

            end;
         end;
   memo1.lines.append('All done!');
   Button4.Enabled :=True;
   Button2.Enabled:=False ;
   Button5.Enabled:=True;
   Button1.Enabled:=False;
   AntiKeyLoggerMemo1.ReadOnly:=True;
     end;   

如何为进程创建进度条？我必须把命令进度条放在哪里？

how do I make a progress bar for the process? and where I have to put the command progress bar?

推荐答案

首先，你需要将代码移动到自己的线程中。否则GUI将不会响应。您还必须确保代码是线程安全的。

First, you need to move the code to its own thread. Otherwise the GUI will not respond. You also have to make sure the code is thread-safe.

无论如何，在线程内，您需要随时更新进度条。如果这样发生，你有一个外部循环和一个内部循环，其中外部循环一次或多次迭代，您可以更新该位置的进度条。如果您只有一个大循环，则可能不想在每次迭代时更新进度条;例如，单个迭代可能仅在几毫秒内完成。

Anyhow, inside the thread, you need to update the progress bar every now and then. If it so happens that you have an outer loop and an inner loop, where the outer loop iterates once a second or so, you could update the progress bar at that place. If you only have one big loop, you might not want to update the progress bar at every iteration; for instance, a single iteration might perhaps be done in only a few milliseconds.

相反，您可以确保每隔一秒更新一次进度条。要实现这一点，您可以使用 GetTickCount ：

Instead, you can make sure to update the progress bar once every second, or so. To accomplish this, you can use GetTickCount:

tc := GetTickCount;
if Terminated then Exit;
if tc - oldtc > 1000 then
begin
  PostMessage(FProgressBarHandle, PBM_SETPOS, TheNewPosition, 0);
  oldtc := tc;
end;

这也显示了一种更新进度条的方法 - 只需发布一条消息！您也可以定义自己的信息并将其发送到主要的。

This also shows a way to update the progress bar -- simply post it a message! You could also define your own message and send it to the main from.

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