ViewPager中子fragment的切换

需求

先简单的说下需求，viewpager中有两个fragment，分别是fragment1，fragment2，在fragment1中有一个按钮，点击这个按钮可以跳转到fragment2

原理

给fragment1传递MainActivity中的viewpager对象，然后调用其viewpager对象的setCurrentItem()方法即可。

代码

MainActivity.java

public class MainActivity extends FragmentActivity {

    private VerticalViewPager mViewpager;
    private List<Fragment>  mFragmentList = new ArrayList<>();
    private MyFragment1 mFragment1;
    private MyFragment2 mFragment2;
    private FragmentManager mManager;
    private MyAdapter mAdapter;
    private FragmentSkipInterface mFragmentSkipInterface;

    public void setFragmentSkipInterface(FragmentSkipInterface fragmentSkipInterface) {
        mFragmentSkipInterface = fragmentSkipInterface;
    }

    /** Fragment跳转 */
    public void skipToFragment(){
        if(mFragmentSkipInterface != null){
            mFragmentSkipInterface.gotoFragment(mViewpager);
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {

        mViewpager = (VerticalViewPager) findViewById(viewpager);

        mFragment1 = new MyFragment1();
        mFragment2 = new MyFragment2();
        mFragmentList.add(mFragment1);
        mFragmentList.add(mFragment2);

        mManager = getSupportFragmentManager();

        mAdapter = new MyAdapter(mManager,mFragmentList);
        mViewpager.setAdapter(mAdapter);
        mAdapter.notifyDataSetChanged();

    }
    public interface FragmentSkipInterface {
        /** ViewPager中子Fragment之间跳转的实现方法 */
        void gotoFragment(VerticalViewPager viewPager);
    }
}

fragement1.java

public class MyFragment1 extends Fragment implements View.OnClickListener {

    private Button mBtn;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment1_layout,container,false);
        return view;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mBtn = view.findViewById(R.id.btnClick);
        mBtn.setOnClickListener(this);

    }

    @Override
    public void onClick(View view) {

        final MainActivity mainActivity = (MainActivity) getActivity();
        mainActivity.setFragmentSkipInterface(new MainActivity.FragmentSkipInterface() {
            @Override
            public void gotoFragment(VerticalViewPager viewPager) {
                /** 跳转到第二个页面的逻辑 */
                viewPager.setCurrentItem(1);
            }
        });
        /** 进行跳转 */
        mainActivity.skipToFragment();
    }
}