安卓实战简单新闻客户端2

注意，我们现在的主界面还是空的，不过我们在主界面里留下了一个FrameLayout布局，对于不同的切换就是在Fragment的切换，也就是Fragment的动态添加。

再看一次原作者的新闻界面:

很容易看出来是Viewpage加上TabLayout的应用，关于这个
我也写过相关文章: android-UI-viewpager--PagerTabStrip的使用---网易云探索(2)
也可以参考文章:ViewPager实现页卡的最新方法--简洁的TabLayout

Fragment布局文件：

fragment_news:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.design.widget.TabLayout
        android:id="@+id/tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabSelectedTextColor="@color/colorPrimaryDark"
        app:tabTextColor="#000"/>

    <!--可滑动的布局内容-->
    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

FragmentNews:
注意我们要做一个fragment里面嵌套fragment:先不嵌套

public class NewsFragment extends Fragment {

    public static final int NEWS_TYPE_TOP = 0;
    public static final int NEWS_TYPE_NBA = 1;
    public static final int NEWS_TYPE_CARS = 2;
    public static final int NEWS_TYPE_JOKES = 3;

    private TabLayout mTablayout;
    private ViewPager mViewPager;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_news, null);
        mTablayout = (TabLayout) view.findViewById(R.id.tab_layout);
        mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
        mViewPager.setOffscreenPageLimit(3);
        setupViewPager(mViewPager);
        mTablayout.addTab(mTablayout.newTab().setText(R.string.top));
        mTablayout.addTab(mTablayout.newTab().setText(R.string.nba));
        mTablayout.addTab(mTablayout.newTab().setText(R.string.cars));
        mTablayout.addTab(mTablayout.newTab().setText(R.string.jokes));
        mTablayout.setupWithViewPager(mViewPager);
        return view;
    }

    private void setupViewPager(ViewPager mViewPager) {
        //Fragment中嵌套使用Fragment一定要使用getChildFragmentManager(),否则会有问题
//        MyPagerAdapter adapter = new MyPagerAdapter(getChildFragmentManager());
//        adapter.addFragment(NewsListFragment.newInstance(NEWS_TYPE_TOP), getString(R.string.top));
//        adapter.addFragment(NewsListFragment.newInstance(NEWS_TYPE_NBA), getString(R.string.nba));
//        adapter.addFragment(NewsListFragment.newInstance(NEWS_TYPE_CARS), getString(R.string.cars));
//        adapter.addFragment(NewsListFragment.newInstance(NEWS_TYPE_JOKES), getString(R.string.jokes));
        //     mViewPager.setAdapter(adapter);
    }

    public static class MyPagerAdapter extends FragmentPagerAdapter {
        private final List<Fragment> mFragments = new ArrayList<>();
        private final List<String> mFragmentTitles = new ArrayList<>();

        public MyPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        public void addFragment(Fragment fragment, String title) {
            mFragments.add(fragment);
            mFragmentTitles.add(title);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragments.get(position);
        }

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

        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitles.get(position);
        }
    }
}

监听按钮，动态添加fragment:

@Override
                    public boolean onNavigationItemSelected(MenuItem menuItem) {
                        Toast.makeText(getApplicationContext(),
                                menuItem.getTitle(), Toast.LENGTH_LONG).show();
                                switch (menuItem.getItemId()){
                                    case R.id.navigation_news:
                                        getSupportFragmentManager().beginTransaction().replace(R.id.frame_content, new NewsFragment()).commit();
                                        mToolbar.setTitle("新闻");
                                        break;
                                    default:
                                        break;
                                }

                        menuItem.setChecked(true);
                        mDrawerLayout.closeDrawers();
                        return true;
                    }

测试: