Android: how to draw an ImageView with the same size regardless of device?
<p>I want to put a toolbar in my application.  The toolbar will use ImageViews as application buttons.  I would like the ImageViews to be the exact same size regardless device; by "same size" I mean that, when rendered to the screen, if I measure them with a ruler, the dimensions will be the same.  I would like this size to be ~10mm (the width of my index finger).  </p>

<p>I have been completely unsuccessful in accomplishing this.</p>

<p>I am testing on a MDPI, large screen Acer Iconia Tab and a HDPI medium screen Samsung Galaxy Tab. If I set <code>layout_width="50dip"</code> and <code>layout_height="50dip"</code>, the buttons render as ~10mm on the Samsung, and ~8mm on the Acer.  If I set the buttons as <code>layout_width="12mm"</code> and <code>layout_height="12mm"</code>, they render as 12mm on the Acer and ~9mm on the Galaxy (confusing that 50dip renders bigger on the Galaxy than the Acer, but 12 mm renders smaller on the Galaxy than on the Acer).  </p>

<p>If I place a 32pix x 32pix icon in my drawable-mdpi folder (and no equivalent in the drawable-hdpi folder), and set <code>layout_width="wrap_content"</code> and <code>layout_height="wrap_content"</code>; the results are similar to if set to 50dip, the Samsung is about 10mm, the Acer about 8mm.  If I add a 48pix x 48pix icon to my drawable-hdpi folder, there is no change; presumably because the Acer still uses the mdpi icon and the Samsung uses the bigger one, but scales it down by 50% because it knows its hdpi (if am confident that this surprising scaling occurs because if I move the 48pix icon to the mdpi folder, and have nothing in the hdpi folder, the icon shows very large on the Samsung).</p>

<p>I am confused and could really use advice.  How do I make my button fingertip sized regardless of dpi and screen size? </p>
