procedure ToInstallApk(filename: string);

var

   aFile: Jfile;

   Intent: JIntent;

begin

      Try

          aFile := TJfile.JavaClass.init(stringtojstring(DownPath),stringtojstring(filename));

          Intent := TJIntent.Create;

          Intent.setAction(TJIntent.JavaClass.ACTION_VIEW);

          Intent.addFlags(TJIntent.JavaClass.FLAG_ACTIVITY_NEW_TASK);

          Intent.setDataAndType(TJnet_Uri.JavaClass.fromFile(aFile), stringtojstring('applicationnd.android.package-archive'));

          SharedActivityContext.startActivity(Intent);

      Except

      End;

end;

procedure ToInstallApk70(filename: string);

var

  LFile: JFile;

  LIntent: JIntent;

  LNet_Uri: Jnet_Uri;

begin

  if not TOSVersion.Check(7, 0) then

  begin

       ToInstallApk(filename);

       exit;

  end;

  LFile := TJFile.JavaClass.init(StringToJString(ExtractFilePath(DownPath)), StringToJstring(ExtractFileName(filename)));

  LIntent := TJIntent.Create;

  if TOSVersion.Check(8, 0) then

    LIntent.setAction(TJIntent.JavaClass.ACTION_INSTALL_PACKAGE)

  else

    LIntent.setAction(TJIntent.JavaClass.ACTION_VIEW);

  LIntent.addFlags(TJIntent.JavaClass.FLAG_ACTIVITY_NEW_TASK);

  if TOSVersion.Check(7, 0) then

  begin

    // fix: android.os.FileUriExposedException: exposed beyond app through Intent.getData()

    // Project -> Options -> Application -> Entitlement List -> Secure File Sharing -> Check it

    LIntent.addFlags(TJIntent.JavaClass.FLAG_GRANT_READ_URI_PERMISSION);

    LNet_Uri := TJFileProvider.JavaClass.getUriForFile(TAndroidHelper.Context,

      StringToJString(JStringToString(TAndroidHelper.Context.getPackageName) + '.fileprovider'), LFile);

  end

  else

    LNet_Uri := TJnet_Uri.JavaClass.fromFile(LFile);

  LIntent.setDataAndType(LNet_Uri, StringToJString('applicationnd.android.package-archive'));

  TAndroidHelper.Context.startActivity(LIntent);

end;

来源：https://www.cnblogs.com/kinglandsoft/p/11934682.html