Question

我正在尝试将TabLayout和BottomNavigationView合并到一个TabsActivity.java文件中。 TabLayout工作正常，但遇到BottomNavigationView的问题。它不会在ViewPager ( @+id/container )上显示其片段页面内容，但会隐藏并显示TabLayout，这意味着它正在通过switch (item.getItemId()) {个案例。

它在应用启动期间加载第一页但是一旦我点击底部标签，我看到的每个标签上都有白页。知道如何解决这个问题吗？

的java

public class TabActivity extends AppCompatActivity {

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


        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        final SectionsPagerAdapter mSectionsPagerAdapter;
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        final ViewPager mViewPager;

        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        final TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);

        BottomNavigationView bottomNavigationView = (BottomNavigationView)
                findViewById(R.id.navigation);

        bottomNavigationView.setOnNavigationItemSelectedListener
                (new BottomNavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                        Fragment selectedFragment = null;
                        switch (item.getItemId()) {
                            case R.id.action_item1:
                                selectedFragment = HomeTab.newInstance();
                                tabLayout.setVisibility(View.VISIBLE);
                                break;
                            case R.id.action_item2:
                                selectedFragment = StatusTab.newInstance();
                                tabLayout.setVisibility(View.GONE);
                                break;
                        }
                        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
                        transaction.replace(R.id.container, selectedFragment);
                        transaction.commit();
                        return true;
                    }
                });

        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.container, HomeTab.newInstance());
        transaction.commit();


    }

    public void do_refresh(View v){
        //try refresh onclick
    }


    private class SectionsPagerAdapter extends FragmentPagerAdapter {

        private SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position){
                case 0:
                    return new HomeTab();
                case 1:
                    return  new SecondTab();
                case 2:
                    return  new ThirdTab();
                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "Home";
                case 1:
                    return "Second";
                case 2:
                    return "Third";
            }
            return null;
        }
    }
}

XML

<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="com.tesrs.serv">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/AppTheme.PopupOverlay">


                <TextView
                    android:id="@+id/custom_toolbar_title"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginEnd="20dp"
                    android:layout_gravity="end"
                    android:onClick="do_refresh"
                    android:text="test"/>


        </android.support.v7.widget.Toolbar>

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="45dp"
            android:background="@color/greyish"
            app:tabTextColor="@color/inactiveblack"
            app:tabSelectedTextColor="@color/activeblack"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="40dp"
        android:layout_marginTop="85dp"/>


    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_gravity="bottom"
        android:background="@color/greyish"
        app:itemIconTint="@color/black"
        app:itemTextColor="@color/black"
        app:menu="@menu/bottom_tab"/>
</android.support.design.widget.CoordinatorLayout>

Answer 1

transaction.replace(R.id.container, selectedFragment);

应该是您的框架布局要替换为选定的片段，而不是视图分页器

 <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:animateLayoutChanges="true">

    </FrameLayout>

组合TabLayout和BottomNavigationView时发生了错误

1 个答案: