title: app crash when deleting item from array list
body: <p>my app crash when i try to remove object from array list : </p>
  
  <pre><code>for (ColouredPaths p : mTouches) {
              if(erase){
                  if(p!=null)
                  {  mTouches.remove(p);}
  
              }
  </code></pre>
  
  <p>why this is happening and how o fix ?</p>