title: Fragment doesn't display
body: <p>The project is multiple-fragment project. Launch application to start BaseActivity, which all fragments are attached into it.</p>
  
  <p>Issue:</p>
  
  <p>Fragment A is the first fragment and is launched very well.
  Fragment B is trigged by clicking button of Fragment A, also launched very well.
  During from B back to A, the problem occurs. Nothing to display, only background, the BaseActivity.</p>
  
  <p>All fragments use the api "replace" to display, although this API may produce performance problems, please ignore it firstly.</p>
  
  <p>I have tried many methods, but nothing works.</p>
  
  <p>The launched fragment method shows below:</p>
  
  <pre><code>    public void navigateToFragment(Fragment fragment, boolean isClear){
          if(isClear){     
              getSupportFragmentManager()
            .popBackStack(null,FragmentManager.POP_BACK_STACK_INCLUSIVE);
          }
  
      getSupportFragmentManager().beginTransaction()
              .addToBackStack(null)
              .replace(R.id.container,fragment)
              .commit()
  }
  </code></pre>
  
  <p>As I know, popBackStack and replace, commit can lead to one fragment is launched twice, but why no display after replace whatever I replace it?</p>