如何在 Delphi 10.3 平台上从 android 设备检索视频的缩略图？

Question

在 Delphi 10.3 下开发的移动应用程序中，我想显示我从设备的本地存储中选取的视频的缩略图。谁能分享在 Delphi.

中执行此操作的示例代码

根据@Dave Nottage 的建议进行编辑。现在我只需要一种获取所选视频文件的绝对路径的方法。

procedure TForm1.OpenFileSelector(Sender: TObject; const APermissions: TArray<string>;
                                       const AGrantResults: TArray<TPermissionStatus>);

var
  Intent: JIntent;

begin
  FMessageSubscriptionID := TMessageManager.DefaultManager.SubscribeToMessage(TMessageResultNotification,
                                                                               HandleActivityMessage);
  Intent := TJIntent.JavaClass.init(TJIntent.JavaClass.ACTION_PICK);
  Intent.setType(StringToJString('video/*'));
  Intent.setAction(TjIntent.JavaClass.ACTION_GET_CONTENT);
  Intent.putExtra(TJIntent.JavaClass.EXTRA_ALLOW_MULTIPLE, true);
  Tandroidhelper.Activity.startActivityForResult(Intent,0);
  {$ENDIF}
end;
//-----------------------------

procedure TForm1.HandleActivityMessage(const Sender: TObject; const aMessage: TMessage);
// when message is received
begin
  if aMessage is TMessageResultNotification then
    HandleIntentAction(TMessageReceivedNotification(aMessage).Value);
end;

//-------------------------------------------
function TForm1.HandleIntentAction(const Data: JIntent): Boolean;
{code to get the details of the file selected from gallery}
  //============
  function LoadBitmapFromJBitmap(const ABitmap: TBitmap; const AJBitmap: JBitmap): Boolean;
  var
    LSurface: TBitmapSurface;
  begin
    LSurface := TBitmapSurface.Create;
    try
      Result := JBitmapToSurface(AJBitmap, LSurface);
      if Result then
        ABitmap.Assign(LSurface);
    finally
      LSurface.Free;
    end;
  end;
  //---------------
  procedure AssignVideoThumbnails(aPath: string);
  var
    LBitmap: JBitmap;
    LFileName: string;
  begin
   // LFileName := TPath.Combine(TPath.GetDocumentsPath, 'SampleVideo.mp4'); {using the paramter aPath instead}
    LBitmap := TJThumbnailUtils.JavaClass.createVideoThumbnail(StringToJString(aPath), TJImages_Thumbnails.JavaClass.MICRO_KIND); // 96 x 96
    if Assigned(LBitmap) then
      LoadBitmapFromJBitmap(Image1.Bitmap, LBitmap);
  end;
  //============
var
  vURI: JString;
  vFilePath: string;
begin
  if Assigned(Data) then begin
    vURI := Data.getData.getPath;        //getPath returns URI path
    vFilePath := ????                    // I NEED THE ABSOLUTE PATH of the selected file here
    AssignVideoThumbnails(vFilePath);    
  end;
end;

Answer 1

这是一个例子：

uses
  System.IOUtils,
  Androidapi.JNI.Media, Androidapi.Helpers, Androidapi.JNI.GraphicsContentViewText, Androidapi.JNI.Provider,
  FMX.Surfaces, FMX.Helpers.Android;

function LoadBitmapFromJBitmap(const ABitmap: TBitmap; const AJBitmap: JBitmap): Boolean;
var
  LSurface: TBitmapSurface;
begin
  LSurface := TBitmapSurface.Create;
  try
    Result := JBitmapToSurface(AJBitmap, LSurface);
    if Result then
      ABitmap.Assign(LSurface);
  finally
    LSurface.Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  LBitmap: JBitmap;
  LFileName: string;
begin
  LFileName := TPath.Combine(TPath.GetDocumentsPath, 'SampleVideo.mp4');
  LBitmap := TJThumbnailUtils.JavaClass.createVideoThumbnail(StringToJString(LFileName), TJImages_Thumbnails.JavaClass.MICRO_KIND); // 96 x 96
  LoadBitmapFromJBitmap(Image1.Bitmap, LBitmap);
end;

我使用 Deployment Manager 将示例视频部署到 ./assets/internal 的远程路径，在代码中等同于 TPath.GetDocumentsPath。

LoadBitmapFromJBitmap 几乎如其所说：获取一个 JBitmap 并将其放入 TBitmap :-)

如何在 Delphi 10.3 平台上从 android 设备检索视频的缩略图？

How can i retrieve the thumbnails of a video from an android device in a Delphi 10.3 platform?

delphi

android

delphi-10.3-rio