Question

我有一个 AppCompatActivity 和一些片段。操作栏上的后退按钮在AboutFragment中不起作用。

活动没有膨胀的菜单，而“片段”在操作栏中只有一个后退按钮。

片段菜单可见，但是轻按后退按钮完全不起作用。

点击操作栏中的信息图标，就会显示AboutFragment。

在单击i图标时，波纹管方法在MainActivity内部起作用。

 @Override
    public void onInfoSelected() {

        abf = (AboutFragment) getSupportFragmentManager().findFragmentByTag(ABOUT_FRAGMENT_TAG);

        FragmentTransaction ft = fm.beginTransaction();
        ft.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right,
                android.R.anim.slide_in_left, android.R.anim.slide_out_right);
       // ft.hide(pf);

        //ft.hide(cf);
        ft.hide(tlf);
        ft.show(abf);
        ft.addToBackStack(null);
        ft.commit();
    }

然后，AboutFragment中的后退按钮不会调用Fragment中的onOptionsItemSelected()方法。

调试时，我可以看到Fragment和Activity的onCreateOptionsMenu()都被调用，但是当点击按钮时，既没有从Activity也没有从Fragment中调用onOptionsItemSelected()。

我搜索和谷歌搜索已经过了两天，对我没有任何帮助。任何帮助都会得到应用。

活动Java代码

package me.declangao.jiasazsales.app;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

import me.declangao.jiasazsales.R;
import me.declangao.jiasazsales.model.Post;

public class MainActivity extends AppCompatActivity implements
        RecyclerViewFragment.PostListListener, PostFragment.PostListener,
        TabLayoutFragment.TabLayoutListener, SearchResultFragment.SearchResultListener,
        CommentFragment.CommentListener,AboutFragment.AboutListener {

    private static final String TAG = MainActivity.class.getSimpleName();
    public static final String TAB_LAYOUT_FRAGMENT_TAG = "TabLayoutFragment";
    public static final String POST_FRAGMENT_TAG = "PostFragment";
    public static final String COMMENT_FRAGMENT_TAG = "CommentFragment";

    public static final String ABOUT_FRAGMENT_TAG = "AboutFragment";


    private FragmentManager fm = null;
    private TabLayoutFragment tlf;
    private PostFragment pf;
    private CommentFragment cf;
    private SearchResultFragment srf;
    private AboutFragment abf;


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



        fm = getSupportFragmentManager();

        // Setup fragments
        tlf = new TabLayoutFragment();
        pf = new PostFragment();
        cf = new CommentFragment();
        srf = new SearchResultFragment();
        abf=new AboutFragment();
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(android.R.id.content, abf, ABOUT_FRAGMENT_TAG);
        ft.add(android.R.id.content, pf, POST_FRAGMENT_TAG);
        ft.add(android.R.id.content, cf, COMMENT_FRAGMENT_TAG);
        ft.add(android.R.id.content, tlf, TAB_LAYOUT_FRAGMENT_TAG);


        ft.hide(pf);
        ft.hide(cf);
        ft.hide(abf);
        ft.show(tlf);
        ft.commit();
    }

    /**
     * Invoked when a post in the list is selected
     *
     * @param post Selected Post object
     */
    @Override
    public void onPostSelected(Post post, boolean isSearch) {
        // Find the fragment in order to set it up later
        pf = (PostFragment) getSupportFragmentManager().findFragmentByTag(POST_FRAGMENT_TAG);

        // Set necessary arguments
        Bundle args = new Bundle();
        args.putInt("id", post.getId());
        args.putString("title", post.getTitle());
        args.putString("date", post.getDate());
        args.putString("author", post.getAuthor());
        args.putString("content", post.getContent());
        args.putString("url", post.getUrl());
        //args.putString("thumbnailUrl", post.getThumbnailUrl());
        args.putString("featuredImage", post.getFeaturedImageUrl());

        // Configure PostFragment to display the right post
        pf.setUIArguments(args);

        // Show the fragment
        FragmentTransaction ft = fm.beginTransaction();
        ft.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right,
                android.R.anim.slide_in_left, android.R.anim.slide_out_right);
        if (!isSearch) { // Hide TabLayoutFragment if this is not search result
            ft.hide(tlf);

        } else { // Otherwise, hide the search result, ie. SearchResultFragment.
            ft.hide(srf);
        }
        ft.show(pf);
        ft.addToBackStack(null);
        ft.commit();
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                //do something here like
Log.e("menu Test","rom Main activity");
                int backStackEntryCount
                        =getSupportFragmentManager().getBackStackEntryCount();

                if (backStackEntryCount > 0) {

                    getSupportFragmentManager().popBackStack();

                }

                return true;
        }
        return false;
    }
    /**
     * Invoked when a search query is submitted
     *
     * @param query Selected Post object
     */
    @Override
    public void onSearchSubmitted(String query) {
        FragmentTransaction ft = fm.beginTransaction();
        ft.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right,
                android.R.anim.slide_in_left, android.R.anim.slide_out_right);

        // Send query to fragment using factory method
        srf = SearchResultFragment.newInstance(query);
        ft.add(android.R.id.content, srf);
        ft.hide(tlf);
        ft.addToBackStack(null);
        ft.commit();
    }


    @Override
    public void onInfoSelected() {

        abf = (AboutFragment) getSupportFragmentManager().findFragmentByTag(ABOUT_FRAGMENT_TAG);

        FragmentTransaction ft = fm.beginTransaction();
        ft.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right,
                android.R.anim.slide_in_left, android.R.anim.slide_out_right);
       // ft.hide(pf);

        //ft.hide(cf);
        ft.hide(tlf);
        ft.show(abf);
        ft.addToBackStack(null);
        ft.commit();
    }
    /**
     * Invoked when comment menu is selected
     *
     * @param id ID of the article, assigned by WordPress
     */
    @Override
    public void onCommentSelected(int id) {
        cf = (CommentFragment) getSupportFragmentManager().findFragmentByTag(COMMENT_FRAGMENT_TAG);
        Bundle args = new Bundle();
        args.putInt("id", id);
        // Setup CommentFragment to display the right comments page
        cf.setUIArguments(args);

        FragmentTransaction ft = fm.beginTransaction();
        ft.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right,
                android.R.anim.slide_in_left, android.R.anim.slide_out_right);
        ft.hide(pf);
        //ft.hide(abf);
        ft.show(cf);
        ft.addToBackStack(null);
        ft.commit();
    }

    /**
     * Intercept back button event, reset ActionBar if necessary
     */
    @Override
    public void onBackPressed() {
        resetActionBarIfApplicable();
        super.onBackPressed();
    }

    /**
     * Simulate a back button press when home is selected
     */
    @Override
    public void onHomePressed() {
        resetActionBarIfApplicable();
        fm.popBackStack();
    }

    /**
     * Reset TabLayoutFragment's ActionBar if necessary
     */
    private void resetActionBarIfApplicable() {
        Log.d(TAG, "SearchResultFragment is visible: " + srf.isHidden());
        if (srf.isVisible()) {
            tlf.resetActionBar();
        }
    }

    // Commented out coz we will let fragments handle their own Options Menus
/*
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        //Log.e("Erroraaa","aaaaa");

        return true;
    }



    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        Log.e("menu","activity: action home has clicked");
        switch (item.getItemId()){
            case android.R.id.home:

                onBackPressed();
                return false;

        }

        return super.onOptionsItemSelected(item);
    }
*/

}

AboutFragment

 package me.declangao.jiasazsales.app;

import android.app.Activity;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import me.declangao.jiasazsales.R;

/**
 * Fragment to display a Info about Jiasaz company.
 * Activities that contain this fragment must implement the
 * {@link AboutFragment.AboutListener} interface
 * to handle interaction events.
 */
public class AboutFragment extends Fragment {



    private AboutListener mListener;
    private Toolbar toolbar;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setRetainInstance(true);

        this.setHasOptionsMenu(true);

    }

//    @Override
//    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
//        Log.e("Menu:created","Menu");
//
////        super.onCreateOptionsMenu(menu, inflater);
////        menu.clear();
//        inflater.inflate(R.menu.menu_post, menu);
//        super.onCreateOptionsMenu(menu, inflater);
//    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Log.e("Menu:selected","Menu");
        if (item.getItemId() == android.R.id.home) {
            mListener.onHomePressed();
        }
        return false;
    }


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

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

        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.about_layout, container, false);

        toolbar = (Toolbar) rootView.findViewById(R.id.toolbar);
        ((MainActivity) getActivity()).setSupportActionBar(toolbar);
        ((MainActivity) getActivity()).getSupportActionBar().setHomeButtonEnabled(true);
        ((MainActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        ((MainActivity) getActivity()).getSupportActionBar().setTitle(  "www.Jiasaz.com");
         Log.e("Menu: fragment created","onCreaate()");

        return rootView;
    }

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

    @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 AboutListener {
       void onHomePressed();
        //void onInfoSelected();
    }




}

这是我的AboutFragment xml代码

<FrameLayout 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:background="@color/colorAccent"
    android:layoutDirection="rtl"
    android:textDirection="rtl"

    tools:context="me.declangao.jiasazsales.app.AboutFragment">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layoutDirection="rtl"
        android:textDirection="rtl"
        android:orientation="vertical">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/colorPrimary"
            android:theme="@style/ThemeOverlay.AppCompat.Dark"
            android:layoutDirection="rtl"
            android:textDirection="rtl"
            />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layoutDirection="rtl"
        android:textDirection="rtl"
        android:padding="15dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/textView2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:layout_marginBottom="10dp"
            android:text="ئه‌م ئاپه‌ له‌لایه‌ن كۆمپانیای جیاساز دروست كراوه‌"
            android:textAppearance="@style/TextAppearance.AppCompat.Light.SearchResult.Title" />

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="match_parent"
            android:layout_height="214dp"
            android:src="@drawable/jiasazlogo" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:layout_marginBottom="10dp"
            android:text="كۆمپانیای جیاساز بۆ خزمه‌تگوزاری و چاره‌سه‌ری ته‌كنه‌لۆجی، دروستكردنی وێبسایت و ئاپی مۆبایل و سیسته‌می دام و ده‌زگاكان و ماركێته‌كان"
            android:textAppearance="@style/TextAppearance.AppCompat.Light.SearchResult.Title" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:autoLink="all"
            android:clickable="true"
            android:text="@string/link"
            android:textAlignment="center"
            android:textAppearance="@style/TextAppearance.AppCompat.Body1"
            android:textSize="18sp" />

    </LinearLayout>
    </LinearLayout>

</FrameLayout>

Answer 1

您可以直接在OnMenuItemClickListener上设置Toolbar的实例。请记住，您不应使用 Activity.setSupportActionBar(Toolbar)。

public class AboutFragment extends Fragment {

    // ...

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

        View rootView = inflater.inflate(R.layout.about_layout, container, false);
        toolbar = (Toolbar) rootView.findViewById(R.id.toolbar);

        toolbar.inflateMenu(R.menu.menu_about_fragment);
        toolbar.setOnMenuItemClickListener(new Toolbar.OnMenuItemClickListener() {

            @Override
            public boolean onMenuItemClick(MenuItem item) {
                if (item.getItemId() == R.id.some_menu) {
                    // do sth...
                    return true; // event is handled.
                }
                return false;
            }
        });

        // ...
    }

    // ...
}

。

更新21/11/2018：

要为独立的Toolbar启用后退按钮，请使用xml在app:navigationIcon="?attr/homeAsUpIndicator"文件中设置其默认图标：

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    android:theme="@style/ThemeOverlay.AppCompat.Dark"
    android:layoutDirection="rtl"
    android:textDirection="rtl"
    app:navigationIcon="?attr/homeAsUpIndicator" />

然后为其设置一个侦听器

toolbar.setNavigationOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // back button is pressed
        mListener.onHomePressed();
    }
});

Answer 2

您正确地描述了所有内容，这些都是平台的局限性。要解决此问题，您需要使用onOptionsItemSelected（）在MainActivity中，插入您已在其他方法中使用的代码：

abf = (AboutFragment) getSupportFragmentManager().findFragmentByTag(ABOUT_FRAGMENT_TAG);

然后，有了片段，您可以从片段中调用某些方法，并可能获取返回值，以了解是否处理了背面以及是否需要做更多的事情...

Answer 3

您可以在片段类中使用onPrepareOptionsMenu(Menu menu)来收听操作栏菜单...

@Override
public void onPrepareOptionsMenu(Menu menu)
{
    super.onPrepareOptionsMenu(menu);

    // to get an item of menu from action bar you can do it like...
    // this below line will find an item of menu with id action_search...
    MenuItem searchMenuItem = menu.findItem(R.id.action_search);

    // like this you can find other menu items
    // another example is
    MenuItem infoMenuItem = menu.findItem(R.id.action_info);
}

我实际上在片段类中使用搜索视图进行搜索...

Answer 4

第一个原因是，您没有在onCreateOptionsMenu()中正确实现onOptionsItemSelected()和Activity @Override方法，因此Activity也可以取消注释调用它们各自的super方法。

第二个原因是您的onCreateOptionsMenu()代码已注释，需要not。重要的是必须调用超级super.onCreateOptionsMenu(menu, inflater);才能绘制Fragment的菜单

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

并将onOptionsItemSelected()中的Fragment更改为此：

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    Log.e("Menu:selected","Menu");
    if (item.getItemId() == android.R.id.home) {
        mListener.onHomePressed();
        return true;
    }else{
        return super.onOptionsItemSelected(item);
    }

}

现在在Activity中将您的onCreateOptionsMenu()更改为此：

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return super.onCreateOptionsMenu(menu);
    }

和onOptionsItemSelected()：

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    return super.onOptionsItemSelected(item);
}

无法在Fragment

4 个答案:

更新21/11/2018：