安卓的fragment切换+左右滑动

viewpage控件：

public class ShowActivity extends AppCompatActivity {

private ViewPager pager;
private RadioGroup radioGroup;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show);
    ButterKnife.bind(this);

获取资源ID

    pager = findViewById(R.id.viewpager);
    radioGroup = findViewById(R.id.radioGroup);

选中第一个

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

添加fragment页

    final ArrayList<Fragment> list = new ArrayList<>();
    list.add(new FragOne());
    list.add(new FragTwo());
    list.add(new FragThree());
    list.add(new FragFour());
    list.add(new FragFive());

内部类adapter

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

        @Override
        public int getCount() {
            return list.size();
        }
    });

viewpage切换

    pager.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) {

        }
    });

滑动选中相应的下标

    radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup radioGroup, int i) {
            switch (i){
                case R.id.radio0:
                    pager.setCurrentItem(0);
                    break;
                case R.id.radio1:
                    pager.setCurrentItem(1);
                    break;
                case R.id.radio2:
                    pager.setCurrentItem(2);
                    break;
                case R.id.radio3:
                    pager.setCurrentItem(3);
                    break;
                case R.id.radio4:
                    pager.setCurrentItem(4);
                    break;
            }
        }
    });
}