片段方法没有被调用

Question

我已经实现了Android Studio 1.5.1 中给出的导航抽屉。

• 我有 5 个导航抽屉项目，每个项目都有一个片段。每个 Fragment 都有 Share 方法（不常见）。
• 在第一个导航抽屉项目的片段中，可以说 OldStory 片段，我正在使用 Viewpager 进行滑动视图，该视图由 3 个片段和 FragmentStatePagerAdapter 组成。它有 Share 方法。

问题 - Story Fragment 的共享方法每次都会被调用，即使屏幕上显示了其他片段。调试后，我知道 Story 片段中的方法被调用了。 - 如果我禁用 OldStory Fragment，那么一切正常。

我无法解决这个问题。我读了很多问题/答案，但它们与活动和片段方法有关。请帮我解决这个问题。

注意 - OldStory 片段具有扩展 FragmentStatePagerAdapter 类的内部类。此类创建许多故事片段。其他实现方式相同。

public class OldStory extends Fragment {

private StoryPagerAdapter storyPagerAdapter;
private InfiniteViewPager viewPager;
SharedPreferences sharedPreferences;
private int TotalCount;

public OldStory() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // Notify the system to allow an options menu for this fragment.

}



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    final View rootView = inflater.inflate(R.layout.fragment_old_story, container, false);
    viewPager = (InfiniteViewPager) rootView.findViewById(R.id.pager);
    viewPager.setOffscreenPageLimit(0);
    sharedPreferences = getActivity().getSharedPreferences(Startup.PreferenceSETTINGS, Context.MODE_PRIVATE);
    TotalCount = sharedPreferences.getInt(Startup.StoryCount, 4);
    storyPagerAdapter = new StoryPagerAdapter(getFragmentManager());
    PagerAdapter wrappedAdapter = new InfinitePagerAdapter(storyPagerAdapter);
    viewPager.setAdapter(wrappedAdapter);
    viewPager.setCurrentItem(TotalCount-1);

    return rootView;
}

public class StoryPagerAdapter extends FragmentStatePagerAdapter {
    public StoryPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {

        return Story.newInstance(position+1);
    }

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

故事片段方法实现 -

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {

    menu.clear();
    inflater.inflate(R.menu.story, menu);
    getActivity().getMenuInflater().inflate(R.menu.main, menu);
}


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.Refresh:
            // We make sure that the SwipeRefreshLayout is displaying it's refreshing indicator
            if(!visiblity) {
                if (!RefreshLayout.isRefreshing()) {
                    ErrorLayout.setVisibility(View.GONE);
                    RefreshLayout.setRefreshing(true);
                }

                // Start our refresh background task
                initiateRequest(Today);
            }
            return true;

        case R.id.Share:
            //InShort = sharedPreferences.getString(Startup.InShort, null);
            Toast.makeText(getContext(), "Stories", Toast.LENGTH_SHORT).show();
            if (InShort!= null && !InShort.isEmpty())
            {

                Intent sendIntent = new Intent(Intent.ACTION_SEND);
                sendIntent.putExtra(Intent.EXTRA_TEXT, "Hi From Story");
                sendIntent.setType("text/plain");
                startActivity(sendIntent);
            }

            return true;

        default:
            return super.onOptionsItemSelected(item);
    }


}

MainActivity用于切换片段。

public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    displayView(item.getItemId());

    return true;
}

//method to replace Views in ID = content_frame in content_main
public void displayView(int viewID)
{
    fragment = null;
    title = getString(R.string.app_name);

    switch (viewID)
    {
        case R.id.nav_frag0:
            fragment = new OldStory();
            title = getString(R.string.story);
            viewIsAtHome = true;
            break;

        case R.id.nav_frag1:
            fragment = new Fragment1();
            title = getString(R.string.fragment1);
            viewIsAtHome = false;
            break;

        case R.id.nav_frag2:
            fragment = new Fragment2();
            title = getString(R.string.fragment2);
            viewIsAtHome = false;
            break;

        case R.id.nav_frag3:
            fragment = new Fragment3();
            title = getString(R.string.fragment3);
            viewIsAtHome = false;
            break;

        case R.id.nav_frag4:
            fragment = new Fragment4();
            viewIsAtHome = false;
            title = getString(R.string.fragment4);
            break;

        case R.id.nav_share:
            fragment = new Fragment5();
            title = getString(R.string.fragment5);
            viewIsAtHome = false;
            break;

    }

    if (fragment != null)
    {
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.content_frame,fragment);
        ft.commit();
    }

    //set the toolbar title
    if(getSupportActionBar() != null)
    {
        getSupportActionBar().setTitle(title);
    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
}

Answer 1

我不确定这是否真的是您问题的答案，但我注意到您的代码中有一个错误：

storyPagerAdapter = new StoryPagerAdapter(getFragmentManager());

将无法正常工作，因为您需要使用getChildFragmentManager() 来管理片段中的片段。

Answer 2

我试图重现您的问题并编写了这个应用程序，据我所知，这是复制您应用程序的行为：

我已将它的源代码上传到我的 Dropbox - feel free to check it out

如您所见，片段可以正确处理分享按钮的点击。 总是有机会，我没有完全理解你的问题，但我是这样做的：

膨胀此菜单的所有片段（但具有不同的onOptionsItemSelected）：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/nav_share"
        android:icon="@drawable/ic_menu_share"
        app:showAsAction="always"
        android:title="Share" />
</menu>

FragmentA 中我的 SubFragment 类（我在 ViewPager 中使用的类）：

public class SubFragment extends Fragment {

    String msg;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.subfragmnet, container, false);
        setHasOptionsMenu(true);
        rootView.findViewById(R.id.subfragmentFrameLayout).setBackgroundColor(getArguments().getInt("background"));
        msg = getArguments().getString("msg");
        return rootView;
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.menu_fragment, menu);
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.nav_share) {
            Snackbar.make(getView(), "Hello from SubFragment " + msg, Snackbar.LENGTH_LONG).show();
        }

        return super.onOptionsItemSelected(item);
    }
}

FragmentA，第一个Fragment，承载ViewPager并嵌套Fragments：

public class FragmentA extends Fragment {

    PagerAdapter pagerAdapter;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_a, container, false);

        Bundle bundle1 = new Bundle();
        bundle1.putInt("background", Color.RED);
        bundle1.putString("msg", "page 1");

        Bundle bundle2 = new Bundle();
        bundle2.putInt("background", Color.YELLOW);
        bundle2.putString("msg", "page 2");

        Bundle bundle3 = new Bundle();
        bundle3.putInt("background", Color.BLUE);
        bundle3.putString("msg", "page 3");

        Fragment[] fragments = {
                Fragment.instantiate(getContext(), SubFragment.class.getName(), bundle1),
                Fragment.instantiate(getContext(), SubFragment.class.getName(), bundle2),
                Fragment.instantiate(getContext(), SubFragment.class.getName(), bundle3),
        };

        if (pagerAdapter == null) {
            pagerAdapter = new PagerAdapter(getChildFragmentManager(), fragments);
        }

        ViewPager viewPager = (ViewPager)rootView.findViewById(R.id.viewPager);
        viewPager.setAdapter(pagerAdapter);

        return rootView;
    }
}

FragmentB（和FragmentC几乎一样）：

public class FragmentB extends Fragment {

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

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.menu_fragment, menu);
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.nav_share) {
            Toast.makeText(getContext(), "Hello from Fragment B", Toast.LENGTH_LONG).show();
        }

        return super.onOptionsItemSelected(item);
    }
}

Hosting Activity 是标准 NavigationDrawer Activity，它在 Drawer 的项目点击时切换 Fragments。

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        ....

        getSupportFragmentManager().beginTransaction().replace(R.id.container, Fragment.instantiate(this, FragmentA.class.getName())).commit();
    }

    ...

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.nav_camera) {
            getSupportFragmentManager().beginTransaction().replace(R.id.container, Fragment.instantiate(this, FragmentA.class.getName())).commit();
        } else if (id == R.id.nav_gallery) {
            getSupportFragmentManager().beginTransaction().replace(R.id.container, Fragment.instantiate(this, FragmentB.class.getName())).commit();
        } else if (id == R.id.nav_slideshow) {
            getSupportFragmentManager().beginTransaction().replace(R.id.container, Fragment.instantiate(this, FragmentC.class.getName())).commit();
        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

如果我正确理解了您的问题，请告诉我！

无论如何，我希望它会有所帮助。