选项卡活动中的活动为空白

Question

我在我的应用程序中的选项卡 Activity 中创建 ListView。但是当应用程序运行模拟器时显示空白活动。我不知道这是什么问题。请帮忙。我没有在选项卡中获得列表。我在没有选项卡的简单活动中获得列表，但在选项卡活动中看不到列表。如果您需要其他信息，请告诉我。

这是我的 ArtistTab.java 活动

public class ArtistsTab extends Fragment {
    ListView listView1;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.artist, container, false);
        listView1 =(ListView)v.findViewById(R.id.listView);
        return v;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        // add your code here which executes after the execution of onCreateView() method.
        ArrayList<String>my=new ArrayList<>();
        my.add("devesh");
        my.add("devesh");
        my.add("devesh");
        my.add("devesh");
        ArrayAdapter arrayAdapter=new ArrayAdapter(getActivity(), layout.simple_list_item_1,my);
        listView1.setAdapter(arrayAdapter);

    }

}

这是我的主要活动

public class MainActivity extends AppCompatActivity {

    public ViewPagerAdapter pagerAdapter;
    private ViewPager mViewPager;
    private Toolbar toolbar;
    private TabLayout tabLayout;
    public static View rootView;
    public static int tabNo;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        pagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.container);
        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);
        mViewPager.setAdapter(pagerAdapter);
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {


            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                mViewPager.setCurrentItem(tab.getPosition());//setting current selected item over viewpager
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
            }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public static class PlaceholderFragment extends Fragment {

        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();

            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
//              View rootView;

            switch (getArguments().getInt(ARG_SECTION_NUMBER))
            {
                case 1: {
                    rootView = inflater.inflate(R.layout.songs, container, false);

                    break;
                }
                case 2: {
                    rootView = inflater.inflate(R.layout.album, container, false);
                    break;
                }

                case 3: {
                    rootView = inflater.inflate(R.layout.genres, container, false);
                    break;
                }
                case 4: {
                    rootView = inflater.inflate(R.layout.artist, container, false);
                    break;
                }

            }
            return rootView;


        }

    }
}

艺术家标签 xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/listView" />
</RelativeLayout>

Answer 1

试试这个tabs with viewpager

public class MainActivity extends AppCompatActivity {

private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;

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

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

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    viewPager = (ViewPager) findViewById(R.id.viewpager);
    setupViewPager(viewPager);

    tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);
}

private void setupViewPager(ViewPager viewPager) {
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new ArtistsTab(), "ArtistsTab");
    adapter.addFragment(new SongsTab(), "Songs");
   //Do your stuff here
    viewPager.setAdapter(adapter);
}

class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

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

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

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

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