title: Application crashes when setting the text of an EditText
body: <p>Why does my application always crash whenever I try to change the text of an EditText? I have tried
          celc = (EditText) findViewById(R.id.cel) ; 
          far = (EditText) findViewById(R.id.fa) ; 
          Ran = (EditText) findViewById(R.id.ran) ; 
          kelvin = (EditText) findViewById(R.id.kev) ;<br>
          celc.addTextChangedListener(new TextWatcher() {</p>
  
  <pre><code>        @Override
          public void onTextChanged(CharSequence s, int start, int before, int count) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void beforeTextChanged(CharSequence s, int start, int count,
                  int after) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void afterTextChanged(Editable s) {
              // TODO Auto-generated method stub
              String value = s.toString() ;
              double c1 = Double.parseDouble(value) ; 
              double f1 = (32+((9.0/5)*c1));
              double r1 = f1+460 ; 
              double k1 = c1 + 273.0 ;
  
              far.setText(f1+"");
              Ran.setText((r1 + "")); 
              kelvin.setText(k1+""); 
  
          }
      }); but it doesn't work.
  </code></pre>