How can I plot FFT (Fast Fourier Transform) in a for loop?

I have this code, it works until m=numfiles, the last part is a code I used for FFT only for one file but I want to adapt in a for-end loop. Data is in cells. I tried to adapt but it doesn't work.

files= dir('*.avi');
  numfiles=length(files);
  mydata= cell(numfiles,1);
  info=cell(numfiles,1);
  isFileSupported =  true(numfiles, 1) ;
  for j=1:numfiles
    try
        info{j}=mmfileinfo(files(j).name);
        audio = info{j}.Audio
        video = info{j}.Video
    catch ME
        isFileSupported(j) = false;
        continue;
    end
  end
     supportedFiles = files(isFileSupported);
     for k=1:numel(supportedFiles)
         mydata{k}=importdata(supportedFiles(k).name);
     end

      if true
        % code
      end

     m=numfiles

      nfft=2^nextpow2(m);  
      Numnfft=length(nfft);
      x_HannWind=x.*hanning(m); 
      Y=fft(x_HandWind,nfft)/m; %Fast Fourier Transform%

      length(Y);
      Y_mag = abs(Y); %Magnitude  FFT%

      plot(Y_mag);
      xlabel('Frecuence [Hz]')
      ylabel('Magnitude')
      end