title: Make Android sdcard read-only
body: <p>I need to test a scenario where the <code>sdcard</code> (or atleast a particular directory) is <code>read-only</code>. Does anyone know how I can do this on the emulator?  </p>
  
  <p>Basically I want to mount the sdcard as read-only. I tried the following command in <code>adb shell</code>, but it doesn't work.</p>
  
  <pre><code>mount -o remount r /sdcar
  </code></pre>