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java - 如何实现 OnFragmentInteractionListener？

转载 作者：行者123 更新时间：2023-11-29 09:53:07 25 4
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我已经查看了与此相关的其他问题，但我仍然不确定如何使用我正在做的事情来实现 OnFragmentInteractionListener。我正在登录 facebook，我想在我的主要 Activity 中实现 OnFragmentInteractionListener，但我不知道该怎么做，我需要帮助。这是 MainActivity:

package com.eren.valour;


import android.app.ActionBar;
import android.content.Context;
import android.net.Uri;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.Menu;
import android.view.MenuItem;
import android.content.Intent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.Toast;

import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;

import static com.eren.valour.R.id.*;

public class MainScreen extends ActionBarActivity {
    private static final int FBSPLASH = 0;
    private static final int FBSELECTION = 1;
    private static final int FBFRAGMENT_COUNT = FBSELECTION + 1;
    private Fragment[] fragments = new Fragment[FBFRAGMENT_COUNT];
    ImageButton fblogin;
    Session session = Session.getActiveSession();
    private boolean isResumed = false;
    private UiLifecycleHelper uiHelper;
    private Session.StatusCallback callback =
            new Session.StatusCallback() {
                @Override
                public void call(Session session,
                                 SessionState state, Exception exception) {
                    onSessionStateChange(session, state, exception);
                }
            };


    public void onFragmentInteraction(Uri uri) {

    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getSupportActionBar().setDisplayShowCustomEnabled(true);
        setTitle("Valour");
        setContentView(R.layout.activity_main_screen);

        uiHelper = new UiLifecycleHelper(this, callback);
        uiHelper.onCreate(savedInstanceState);
        FragmentManager fm = getSupportFragmentManager();
        fragments[FBSPLASH] = fm.findFragmentById(R.id.splashFragment);
        fragments[FBSELECTION] = fm.findFragmentById(R.id.selectionFragment);

        FragmentTransaction transaction = fm.beginTransaction();
        for (int i = 0; i < fragments.length; i++) {
            transaction.hide(fragments[i]);
        }
        transaction.commit();
        getScreenRes();
    }

    public void getScreenRes() {
        DisplayMetrics display = this.getResources().getDisplayMetrics();
        int screenwidth = display.widthPixels;
        double buttonheight = screenwidth / 2.66666667;
        int screenheight = (int) Math.round(buttonheight);

//      ImageButton serviceList = (ImageButton) findViewById(R.id.addservice);
//      ViewGroup.LayoutParams servicelist = serviceList.getLayoutParams();
//      servicelist.width = screenwidth;
//      servicelist.height = screenheight;


        //Get screen dimensions and define button variables
        ImageButton redditLogin = (ImageButton) findViewById(R.id.redditLogin);
        ViewGroup.LayoutParams reddit = redditLogin.getLayoutParams();
        reddit.width = screenwidth;
        reddit.height = screenheight;

        ImageButton fbLogin = (ImageButton) findViewById(R.id.facebookLogin);
        ViewGroup.LayoutParams fb = fbLogin.getLayoutParams();
        fb.width = screenwidth;
        fb.height = screenheight;


        ImageButton instaLogin = (ImageButton) findViewById(R.id.instagramLogin);
        ViewGroup.LayoutParams insta = instaLogin.getLayoutParams();
        insta.width = screenwidth;
        insta.height = screenheight;

        ImageButton twitLogin = (ImageButton) findViewById(R.id.twitterLogin);
        ViewGroup.LayoutParams twit = twitLogin.getLayoutParams();
        twit.width = screenwidth;
        twit.height = screenheight;

//      set button size
        instaLogin.setLayoutParams(insta);
        fbLogin.setLayoutParams(fb);
        twitLogin.setLayoutParams(twit);
        redditLogin.setLayoutParams(reddit);
    }

    public void facebookLogin(View v) {

        if (session == null) {
            session = new Session(getApplicationContext());
        }
        Session.setActiveSession(session);


    }

    public void instagramLogin(View v) {
        serviceIncomplete();


    }

    public void redditLogin(View v) {
        serviceIncomplete();


    }

    public void twitterLogin(View v) {
        serviceIncomplete();


    }

    private void showFragment(int fragmentIndex, boolean addToBackStack) {
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction transaction = fm.beginTransaction();
        for (int i = 0; i < fragments.length; i++) {
            if (i == fragmentIndex) {
                transaction.show(fragments[i]);
            } else {
                transaction.hide(fragments[i]);
            }
        }
        if (addToBackStack) {
            transaction.addToBackStack(null);
        }
        transaction.commit();
    }

    private void onSessionStateChange(Session session, SessionState state, Exception exception) {
        // Only make changes if the activity is visible
        if (isResumed) {
            FragmentManager manager = getSupportFragmentManager();
            // Get the number of entries in the back stack
            int backStackSize = manager.getBackStackEntryCount();
            // Clear the back stack
            for (int i = 0; i < backStackSize; i++) {
                manager.popBackStack();
            }
            if (state.isOpened()) {
                // If the session state is open:
                // Show the authenticated fragment
                showFragment(FBSELECTION, false);
            } else if (state.isClosed()) {
                // If the session state is closed:
                // Show the login fragment
                showFragment(FBSPLASH, false);
            }
        }
    }

    @Override
    protected void onResumeFragments() {
        super.onResumeFragments();
        Session session = Session.getActiveSession();

        if (session != null && session.isOpened()) {
            // if the session is already open,
            // try to show the selection fragment
            showFragment(FBSELECTION, false);
        } else {
            // otherwise present the splash screen
            // and ask the person to login.
            showFragment(FBSPLASH, false);
        }
    }

    //show toast if service is not finished.
    public void serviceIncomplete() {
        Context context = getApplicationContext();
        CharSequence text = "Coming Soon!";
        int duration = Toast.LENGTH_LONG;

        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    }

    public void firstTime() {
        startActivity(new Intent(getApplicationContext(), FirstTimeLogin.class));
    }


    @Override
    public void onResume() {
        super.onResume();
        uiHelper.onResume();
        isResumed = true;
    }

    @Override
    public void onPause() {
        super.onPause();
        uiHelper.onPause();
        isResumed = false;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        uiHelper.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        uiHelper.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        uiHelper.onSaveInstanceState(outState);
    }

}

这是 fragment :

package com.eren.valour;

import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link FacebookLoginDialogueFragment.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link FacebookLoginDialogueFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class FacebookLoginDialogueFragment extends android.support.v4.app.Fragment {
    // 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 FacebookLoginDialogueFragment() {
        // 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 FacebookLoginDialogueFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static FacebookLoginDialogueFragment newInstance(String param1, String param2) {
        FacebookLoginDialogueFragment fragment = new FacebookLoginDialogueFragment();
        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) {
        View view = inflater.inflate(R.layout.fragment_facebook_login_dialogue,
                container, false);
        return view;
    }

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

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (OnFragmentInteractionListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

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

    /**
     * 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.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        public void onFragmentInteraction(Uri uri);
    }

}

我遇到了这个错误

03-27 03:45:57.880    2139-2139/com.eren.valour E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.eren.valour, PID: 2139
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eren.valour/com.eren.valour.MainScreen}: android.view.InflateException: Binary XML file line #20: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
        at android.app.ActivityThread.access$800(ActivityThread.java:144)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
 Caused by: android.view.InflateException: Binary XML file line #20: Error inflating class fragment
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
        at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
        at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
        at com.eren.valour.MainScreen.onCreate(MainScreen.java:55)
        at android.app.Activity.performCreate(Activity.java:5933)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
 Caused by: java.lang.ClassCastException: com.eren.valour.MainScreen@7e027fd must implement OnFragmentInteractionListener
        at com.eren.valour.FacebookLoginDialogueFragment.onAttach(FacebookLoginDialogueFragment.java:85)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
        at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1206)
        at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2159)
        at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:297)
        at android.support.v7.app.ActionBarActivity.onCreateView(ActionBarActivity.java:547)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
            at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
            at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
            at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
            at com.eren.valour.MainScreen.onCreate(MainScreen.java:55)
            at android.app.Activity.performCreate(Activity.java:5933)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

最佳答案

重写方法 onAttach(Activity activity) 现在已在 android.app.Fragment 中弃用，代码应升级为 onAttach(Context context)

这意味着您无需实现此监听器，只需使用以下内容即可:

代替: 

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        mListener = (OnFragmentInteractionListener) activity;
    } catch (ClassCastException e) {
        throw new ClassCastException(activity.toString()
                + " must implement OnFragmentInteractionListener");
    }
}

使用 

@Override
public void onAttach(Context context) {
    super.onAttach(context);
}

关于java - 如何实现 OnFragmentInteractionListener？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29292942/

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