title: negative number input(EditText) getting unsigned
body: <p>i'm doing a cable length calculator, and i'm having trouble with negative numbers.</p>
  
  <p>EditTexts are like this</p>
  
  <pre><code>&lt;EditText android:layout_height="wrap_content" android:layout_weight="1" android:inputType="numberDecimal|numberSigned" android:layout_width="40px" android:id="@+id/rxmax"&gt;
          &lt;/EditText&gt;
  </code></pre>
  
  <p>Then i use them like this:</p>
  
  <pre><code>final EditText rxmax = (EditText) findViewById(R.id.rxmax);
  double RXmax = new Double(rxmax.getText().toString());
  </code></pre>
  
  <p>After i do a simple calculation:</p>
  
  <pre><code>double OPBmax = TXmax - RXmax;
  </code></pre>
  
  <p>Somewhere the inputted negative number turns positive. i'm guessing at the toString conversation but i don't find anything on how to prevent this. </p>