Question

在android下，当我们从图库中选择一个图像时，我们不会收到带扩展名的文件名，而是使用uri而我们必须使用contentprovider将文件复制到我们的本地目录中。

现在因为文件没有任何扩展名，如何在Tbitmap对象中加载它？我尝试但收到错误：无法加载图片。

Answer 1

好的，我确实喜欢这个：

function  DetectImageExtension(const aFileName: string): String;
var aFileStream: TFileStream;
    aFirstBytes: Tbytes;
begin
  aFileStream := TFileStream.Create(aFileName, fmOpenRead);
  try
    if aFileStream.Size < 8 then exit('');
    SetLength(aFirstBytes, 8);
    aFileStream.ReadBuffer(aFirstBytes[0], length(aFirstBytes));
    if (aFirstBytes[0] = $FF) and
       (aFirstBytes[1] = $D8) then result := 'jpg'  // ÿØ
    else if (aFirstBytes[0] = $89) and
            (aFirstBytes[1] = $50) and
            (aFirstBytes[2] = $4E) and
            (aFirstBytes[3] = $47) and
            (aFirstBytes[4] = $0D) and
            (aFirstBytes[5] = $0A) and
            (aFirstBytes[6] = $1A ) and
            (aFirstBytes[7] = $0A) then result := 'png' // .PNG....
    else if (aFirstBytes[0] = $47) and
            (aFirstBytes[1] = $49) and
            (aFirstBytes[2] = $46) then result := 'gif' // GIF
    else if (aFirstBytes[0] = $42) and
            (aFirstBytes[1] = $4D) then result := 'bmp' // BM
    else result := '';
  finally
    aFileStream.Free;
  end;
end;

如何在Tbitmap中加载一个没有任何扩展名的文件？

1 个答案: