必须在Android Studio中实现OnFragmentInteractionListener错误

Question

我想在一个活动中创建一个包含底部导航和标签的应用。但是当我试图将选项卡放在导航片段中时，会出现一个异常。 I want to design like this with two toolbars one is bottom navigation and other is tab

请帮忙

LauncherActivity.java

package com.cornicore.dream11statistics;

import android.app.Fragment;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.widget.FrameLayout;
import android.widget.ProgressBar;

public class LauncherActivity extends AppCompatActivity {



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


// Bottom Navigation Start

        BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation);
        bottomNav.setOnNavigationItemSelectedListener(navListner);

        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new HomeFragment()).commit();

// Bottom Navigation

    }


// Bottom Navigation Start
    private BottomNavigationView.OnNavigationItemSelectedListener navListner = new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem item) {

                    android.support.v4.app.Fragment selectedFragment = null;
                    switch(item.getItemId()){
                        case R.id.nav_home:
                            selectedFragment = new HomeFragment();
                            break;

                        case R.id.nav_pointtable:
                            selectedFragment = new PointTableFragment();
                            break;

                        case R.id.nav_share:
                            selectedFragment = new ShareFragment();
                            break;
                    }


                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,selectedFragment).commit();
                    return true;
                }
            };

// Bottom Navigation Start



}

HomeFragment.java

    package com.cornicore.dream11statistics;

import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;

public class HomeFragment extends Fragment implements Tab1.OnNavFragmentInteractionListener,Tab2.OnNavFragmentInteractionListener,Tab3.OnNavFragmentInteractionListener {



    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_home,container,false);

        TabLayout tabLayout = v.findViewById(R.id.tablayout);
        tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);


        final ViewPager viewPager = v.findViewById(R.id.pager);
        final android.support.v4.view.PagerAdapter adapter = new PagerAdapter(getActivity().getSupportFragmentManager(),tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        viewPager.setOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

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

            }

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

            }
        });



        return v;
    }

    public void onNavFragmentInteraction(Uri uri) {

    }


}

Tab1.java

package com.cornicore.dream11statistics;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link Tab1.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link Tab1#newInstance} factory method to
 * create an instance of this fragment.
 */
public class Tab1 extends Fragment {

    ProgressBar progressBar;
    WebView webView;

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public Tab1() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment Tab1.
     */
    // TODO: Rename and change types and number of parameters
    public static Tab1 newInstance(String param1, String param2) {
        Tab1 fragment = new Tab1();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }



    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_tab1, container, false);
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.OnNavFragmentInteractionListener(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }


    public interface OnFragmentInteractionListener {
         void OnNavFragmentInteractionListener(Uri uri);

    }

    public interface OnNavFragmentInteractionListener {
    }


    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */



}

错误：

05-15 11:12:18.862 4926-4926/com.cornicore.dream11statistics E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.cornicore.dream11statistics, PID: 4926
    java.lang.RuntimeException: com.cornicore.dream11statistics.LauncherActivity@c71a909 must implement OnFragmentInteractionListener
        at com.cornicore.dream11statistics.Tab1.onAttach(Tab1.java:93)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1363)
        at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1109)
        at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:996)
        at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:99)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2364)
        at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2322)
        at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:2199)
        at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:651)
        at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:167)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:1236)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:1084)
        at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1614)
        at android.view.View.measure(View.java:18827)
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:716)
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:462)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at android.view.View.measure(View.java:18827)
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:716)
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:462)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2645)
        at android.view.View.measure(View.java:18827)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2136)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1248)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1484)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1139)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6064)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:860)
        at android.view.Choreographer.doCallbacks(Choreographer.java:672)
        at android.view.Choreographer.doFrame(Choreographer.java:608)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:846)
        at android.os.Handler.handleCallback(Handler.java:742)

Viewpager

final ViewPager viewPager = v.findViewById(R.id.pager);
        final android.support.v4.view.PagerAdapter adapter = new PagerAdapter(getActivity().getSupportFragmentManager(),tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        viewPager.setOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

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

            }

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

            }
        });

Answer 1

在这种情况下，您应该在活动中实现不在片段中的侦听器。

public class LauncherActivity extends AppCompatActivity implements Tab1.OnFragmentInteractionListener

这是因为片段中传递的Context来自活动而不是片段。

如果您希望HomeFragment接收活动。你可以做的是在Tab-fragments中为监听器创建公共setter方法。

public void setInteractionListener(OnFragmentInteractionListener mListener){
  this.mListener = mListener;
}

Answer 2

根据您的代码中的这一部分

@Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener");
        }
    }

您似乎正在传递的上下文不是OnFragmentInteractionListener

的实例