使用底部导航中的选项卡切换片段

Question

我正在使用BottomNavigationDemo中的一些代码。我无法通过它们更改片段或内容。我能做什么？一些提示会很好。

MainActivity.java

public class MainActivity
extends AppCompatActivity {
private TabLayout mTabLayout;

private int[] mTabsIcons = {
        R.drawable.ic_recents_selector,
        R.drawable.ic_favorite_selector,
        R.drawable.ic_recents_selector,
        R.drawable.ic_favorite_selector,
        R.drawable.ic_recents_selector,
        R.drawable.ic_place_selector};

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

    // Setup the viewPager
    CustomViewPager viewPager = (CustomViewPager) findViewById(R.id.view_pager);
    MyPagerAdapter pagerAdapter = new MyPagerAdapter(getSupportFragmentManager());

    if (viewPager != null) {
        viewPager.setPagingEnabled(false);
        viewPager.setAdapter(pagerAdapter);
    }

    mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
    if (mTabLayout != null) {
        mTabLayout.setupWithViewPager(viewPager);

        for (int i = 0; i < mTabLayout.getTabCount(); i++) {
            TabLayout.Tab tab = mTabLayout.getTabAt(i);
            if (tab != null)
                tab.setCustomView(pagerAdapter.getTabView(i));
        }

        mTabLayout.getTabAt(0).getCustomView().setSelected(true);
    }
}

private class MyPagerAdapter extends FragmentPagerAdapter {

    public final int PAGE_COUNT = 6;

    private final String[] mTabsTitle = {"Start", "Lager", "Ressourcen", "Fertigungen", "Militär", "Extras"};

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

    public View getTabView(int position) {
        // Given you have a custom layout in `res/layout/custom_tab.xml` with a TextView and ImageView
        View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.custom_tab, null);
        TextView title = (TextView) view.findViewById(R.id.title);
        title.setText(mTabsTitle[position]);
        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        icon.setImageResource(mTabsIcons[position]);
        return view;
    }

    @Override
    public Fragment getItem(int pos) {
        switch (pos) {

            case 0:
                return PageFragment.newInstance(1);
            case 1:
                return PageFragment.newInstance(2);
            case 2:
                return PageFragment.newInstance(3);
            case 3:
                return PageFragment.newInstance(4);
            case 4:
                return PageFragment.newInstance(5);
            case 5:
                return PageFragment.newInstance(6);
        }
        return null;
    }

    @Override
    public int getCount() {
        return PAGE_COUNT;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mTabsTitle[position];
    }
}
}

PageFragment.java

public class PageFragment extends Fragment {
public static final String ARG_PAGE = "ARG_PAGE";
private int mPageNo;

public static PageFragment newInstance(int pageNo) {

    Bundle args = new Bundle();
    args.putInt(ARG_PAGE, pageNo);
    PageFragment fragment = new PageFragment();
    fragment.setArguments(args);
    return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mPageNo = getArguments().getInt(ARG_PAGE);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_page, container, false);

    TextView textView = (TextView) view.findViewById(R.id.text_view);
    textView.setText(getString(R.string.text));

    return view;
}
}

fragment_page.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.v4.widget.NestedScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/text_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:text="Test"
    android:textSize="24sp"
    android:textAlignment="center"
    android:layout_marginTop="56dp" />
</android.support.v4.widget.NestedScrollView>

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="de.trade_elite.tradeelite.MainActivity">

    <android.support.v7.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/colorPrimary"
        android:theme="?attr/actionBarTheme"
        android:minHeight="?attr/actionBarSize"
        android:id="@+id/toolbar" />

    <TextView
        android:text="@string/name"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/textView13"
        android:layout_weight="1" />

    <de.trade_elite.tradeelite.CustomViewPager

        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="56dp"
        android:layout_weight="1"
        android:layout_marginBottom="64dp">

    </de.trade_elite.tradeelite.CustomViewPager>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:orientation="vertical"
        app:layout_behavior="de.trade_elite.tradeelite.BottomNavigationBehavior"
        app:tabLayoutId="@+id/tab_layout"
        >

        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            style="@style/AppTabLayout"
            android:layout_width="match_parent"
            android:background="?attr/colorPrimary"
            app:tabMode="scrollable"
            android:layout_height="64dp" />

    </FrameLayout>    

</android.support.design.widget.CoordinatorLayout>