title: Save Bitmap into File and return File having bitmap image
body: <p>I have a problem to save Bitmaps into files.
  My method is like this:</p>
  
  <pre><code>private File savebitmap(Bitmap bmp) {
      String extStorageDirectory = Environment.getExternalStorageDirectory()
              .toString();
      OutputStream outStream = null;
  
      File file = new File(bmp + ".png");
      if (file.exists()) {
          file.delete();
          file = new File(extStorageDirectory, bmp + ".png");
          Log.e("file exist", "" + file + ",Bitmap= " + bmp);
      }
      try {
          outStream = new FileOutputStream(file);
          bmp.compress(Bitmap.CompressFormat.PNG, 100, outStream);
          outStream.flush();
          outStream.close();
      } catch (Exception e) {
          e.printStackTrace();
      }
      Log.e("file", "" + file);
      return file;
  
  }
  </code></pre>
  
  <p>It gives me error of file.I am calling this method like this:</p>
  
  <pre><code>Drawable d = iv.getDrawable();
  Bitmap bitmap = ((BitmapDrawable) d).getBitmap();
  File file = savebitmap(bitmap);
  </code></pre>
  
  <p>Please help me...</p>