安卓开发通过ViewPage和RadioButton+SharedPreferences实现欢迎页

新手上路，各位大佬帮忙改错啊

之前看了很多欢迎页的例子，自己研究了好久，做了一个，结合了大佬的资源，做了一个。各位前辈帮忙提意见

private void initView() {
    //初始化单选按钮
    ra = (RadioGroup) findViewById(R.id.group);
    radio1 = (RadioButton) findViewById(R.id.ra1);
    radio2 = (RadioButton) findViewById(R.id.ra2);
    radio3 = (RadioButton) findViewById(R.id.ra3);
    viewPager = (ViewPager) findViewById(R.id.viewPager);
    listview = new ArrayList<>();

    View v1 = getLayoutInflater().inflate(R.layout.tab1, null);
    View v2 = getLayoutInflater().inflate(R.layout.tab2, null);
    View v3 = getLayoutInflater().inflate(R.layout.tab3, null);



    listview.add(v1);
    listview.add(v2);
    listview.add(v3);


    myAdapter = new MyAdapter(listview);
    viewPager.setAdapter(myAdapter);
    //新的监听事件
   viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
       @Override
       public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

       }

       @Override
       public void onPageSelected(int position) {
           switch (position) {
               case 0:
                   radio1.setChecked(true);
                   radio2.setChecked(false);
                   radio3.setChecked(false);
                   break;
               case 1:
                   radio1.setChecked(false);
                   radio2.setChecked(true);
                   radio3.setChecked(false);
                   break;
               case 2:
                   radio1.setChecked(false);
                   radio2.setChecked(false);
                   radio3.setChecked(true);
                   break;

           }



       }


       public void onPageScrollStateChanged(int state) {

       }
   });