title: add in arraylist automaticlly and error while try to clear() arraylist
body: <p>In my module ,I pass arraylist threw intent. but when i open my activity it added automatic. When i try to clear my arraylist in onResume() of parent activity it seems this type of error :- </p>
  
  <blockquote>
    <p>The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged!</p>
  </blockquote>
  
  <p>My code is here :- </p>
  
  <p>This is <strong>PreExamActivity.kt</strong> here click event of exam start Button.</p>
  
  <pre><code>startExam.setOnClickListener {
          //getMarks()
          calculation()
          Common.examqueList = null
          if (numOfQueInSelectedChapter &gt; totalQuestion) {
              val intent = Intent(this, ExamActivity::class.java)
              Common.examqueList = examQueList
              startActivity(intent)
          } else {
              Toast.makeText(this, "Check yr question", Toast.LENGTH_SHORT).show()
          }
      }
  
  override fun onResume() {
      super.onResume()
      Common.examqueList?.clear()
  }
  </code></pre>
  
  <p>Here is my ExamActivity.kt** :-</p>
  
  <pre><code>    queArray = Common.examqueList
      val adpter: PagerAdapter = ExamQuestionPageView(this, queArray!!, question_img_path)
      qPager.adapter = adpter
  </code></pre>