title: (Robotium) How to select a RadioButton in a RadioGroup
body: <p>In my Android app view layout, I have a <code>&lt;RadioGroup&gt;</code> which contains two <code>&lt;RadioButton&gt;</code>:</p>
  
  <pre><code>&lt;RadioGroup
       android:id="@+id/my_radio_group"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:orientation="vertical"&gt;
  
        &lt;RadioButton 
         android:id="@+id/yes_btn"
  
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/yes"
        /&gt;
  
       &lt;RadioButton
         android:id="@+id/no_btn" 
  
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/no"
        /&gt;
  &lt;/RadioGroup&gt;
  </code></pre>
  
  <p>I use <strong><a href="https://code.google.com/p/robotium/" rel="nofollow">Robotium</a></strong> library to write a <strong>JUnit test</strong> for this radio group <strong>to selection one Radio Button</strong>. The test code snippet is:</p>
  
  <pre><code>Solo solo = new Solo(getInstrumentation(), getActivity()); 
  ...
  solo.clickOnRadioButton(R.id.yes_btn); //I expect the "yes" radio button will be selected
  </code></pre>
  
  <p>I expected the above test code would select the "YES" Radio button, But when run it, it raise an <strong>error</strong>:</p>
  
  <pre><code>junit.framework.AssertionFailedError: 2131427675 RadioButtons are not found!
  at com.jayway.android.robotium.solo.Waiter.waitForAndGetView(Waiter.java:417)
  at com.jayway.android.robotium.solo.Clicker.clickOn(Clicker.java:374)
  at com.jayway.android.robotium.solo.Solo.clickOnRadioButton(Solo.java:1063)
  ...
  </code></pre>
  
  <p>How can I select one <code>&lt;RadioButton&gt;</code> in a <code>&lt;RadioGroup&gt;</code> then with <strong><a href="https://code.google.com/p/robotium/" rel="nofollow">Robotium</a></strong>??</p>