Fragement页面 滑动 点击按钮 mainActivty代码

1.找控件

 viewPager = findViewById(R.id.viewpage);
    radioGroup = findViewById(R.id.radiogroup);

2.添加页面

 final ArrayList<Fragment> list = new ArrayList<Fragment>();
    list.add(new Frage_01());
    list.add(new Frage_02());
    list.add(new Frage_03());

3.Fragement 内部类适配器

 viewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
            @Override
            public Fragment getItem(int i) {
                return list.get(i);
            }
            @Override
            public int getCount() {
                return list.size();
            }
        });

4.默认选中第一个页面

radioGroup.check(radioGroup.getChildAt(0).getId());

5.滑动页面按钮跟随

  radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId){
                    case R.id.radiobutton1:
                        viewPager.setCurrentItem(0);
                        break;
                    case R.id.radiobutton2:
                        viewPager.setCurrentItem(1);
                        break;
                    case R.id.radiobutton3:
                        viewPager.setCurrentItem(2);
                         break;
            }
        }
    });

6.点击页面，按钮跟随

      viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {
        }
        @Override
        public void onPageSelected(int i) {
           radioGroup.check(radioGroup.getChildAt(i).getId());
        }
        @Override
        public void onPageScrollStateChanged(int i) {
        }
    });