title: Android How can I load every images from the drawable folder using file to set into the imageItems?
body: <p>How can I load image from drawable folder when I don't know image file name.</p>
  
  <p>I want to show all the drawable folder image in the gridview.</p>
  
  <p>I just know how to load the Image from file name, like below:</p>
  
  <pre><code> // ImageItem  method :public ImageItem(Bitmap imageBitmap, String title){...}
     private ArrayList&lt;ImageItem&gt; getData()
       {
           final ArrayList&lt;ImageItem&gt; imageItems = new ArrayList&lt;&gt;();
           TypedArray imgs = mContext.getResources().obtainTypedArray(R.array.image_ids);
  
           for( int i = 0 ; i&lt; imgs.length(); i++ )
           {
               Bitmap bitmap =      BitmapFactory.decodeResource(mContext.getResources(), imgs.getResourceId(i, -1));
               imageItems.add(new ImageItem(bitmap, "Image#" + i));
           }
  
           return imageItems;
       }
  </code></pre>
  
  <p>But now  if I don't know file name(R.drawable.filename), How can I load every images from the drawable folder using file to set into the imageItems?</p>
  
  <p>Thank you very much.</p>