android - 如何放置 fragment 数组列表可滚动选项卡 Activity ？

Question

我使用RSS提要。其中每个 url 都有很多 rss fragment 。如何使用 1 个 fragment 的 url 数组集。
其中大多数不需要 fragment ，也不需要 url
我只需要
应该使用单个 fragment 并传递多个标题或多个 url 作为参数

 Rssfragment

 adapter.addFrag(new RssFragment(), "news");

 URL rssUrl = new URL("http://www.rssmix.com/u/12847959/rss.xml");

如何设置 arry.how 来联合 ScrollableTabsActivity
如果您知道如何压缩所有 fragment 的问题的答案，请告诉我

  adapter.addFrag(new RssFragment(), "news");
    adapter.addFrag(new RssFragment2(), "cinema news");
    adapter.addFrag(new RssFragment3(), "news");
    adapter.addFrag(new RssFragment4(), "news");
    adapter.addFrag(new RssFragment5(), "news");
    adapter.addFrag(new RssFragment6(), "news");
    adapter.addFrag(new RssFragment7(), "news");
    adapter.addFrag(new RssFragment8(), "news");

如何使用 1 RssFragment 数组设置 url 名称:
这个 ScrollableTabsActivity 这些是要使用的数组

public class ScrollableTabsActivity extends AppCompatActivity {

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

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scrollable_tabs);
        mAdView = findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);
        toolbar = (Toolbar) findViewById(R.id.toolbar2);
        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.addFrag(new RssFragment(), "news");
        adapter.addFrag(new RssFragment2(), "news");
        adapter.addFrag(new RssFragment3(), "news");
        adapter.addFrag(new RssFragment4(), "news");
        adapter.addFrag(new RssFragment5(), "news");
        adapter.addFrag(new RssFragment6(), "news");
        adapter.addFrag(new RssFragment7(), "news");
        adapter.addFrag(new RssFragment8(), "news");

        viewPager.setAdapter(adapter);
    }
    @Override
    public void onBackPressed() {
        new AlertDialog.Builder(this).setIcon(android.R.drawable.ic_dialog_alert).setTitle("Exit")
                .setMessage("Are you sure you want to exit?")
                .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                }).setNegativeButton("No", null).show();
    }

    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 addFrag(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

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

Rssfragment

public class RssFragment extends Fragment {

    private RSSFeed rssFeed = null;
    private ArrayList<RSSItem> postsList;
    private RssAdapter listAdapter;
    private ViewModeUtils viewModeUtils;
    private SwipeRefreshLayout swipeRefreshLayout;

    private Activity mAct;
    private RelativeLayout ll;
    private String url;
    private AdView mAdView;
    private View rootView;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ll = (RelativeLayout) inflater.inflate(R.layout.fragment_list_refresh, container, false);
        return ll;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        setHasOptionsMenu(true);

        RecyclerView listView = ll.findViewById(R.id.list);
        postsList = new ArrayList<>();
        listAdapter = new RssAdapter(getContext(), postsList);
        listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_PROGRESS);
        listView.setAdapter(listAdapter);
        listView.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));

        swipeRefreshLayout = ll.findViewById(R.id.swipeRefreshLayout);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refreshItems();
            }
        });
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mAct = getActivity();

//        url = RssFragment.this.getArguments().getStringArray(MainActivity.FRAGMENT_DATA)[0];
        refreshItems();
    }

    private class RssTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            try {
                URL rssUrl = new URL("http://www.rssmix.com/u/12847959/rss.xml");
                SAXParserFactory mySAXParserFactory = SAXParserFactory.newInstance();
                SAXParser mySAXParser = mySAXParserFactory.newSAXParser();
                XMLReader myXMLReader = mySAXParser.getXMLReader();
                RSSHandler myRSSHandler = new RSSHandler();
                myXMLReader.setContentHandler(myRSSHandler);
                InputSource myInputSource = new InputSource(rssUrl.openStream());
                myXMLReader.parse(myInputSource);

                rssFeed = myRSSHandler.getFeed();

            } catch (ParserConfigurationException | IOException | SAXException e) {
                Log.printStackTrace(e);
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            if (rssFeed != null) {
                if (rssFeed.getList().size() > 0) {
                    postsList.addAll(rssFeed.getList());
                }

                listAdapter.setHasMore(false);
                listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_LIST);
                swipeRefreshLayout.setRefreshing(false);

            } else {
                String message = null;
                if (!url.startsWith("http"))
                    message = "Debug info: '" + url + "' is most likely not a valid RSS url. Make sure the url entered in your configuration starts with 'http' and verify if it's valid XML using https://validator.w3.org/feed/";
                Helper.noConnection(mAct, message);

                listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_EMPTY);
                swipeRefreshLayout.setRefreshing(false);

            }

            super.onPostExecute(result);
        }

    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.rss_menu, menu);
        viewModeUtils = new ViewModeUtils(getContext(), getClass());
        viewModeUtils.inflateOptionsMenu(menu, inflater);
        ThemeUtils.tintAllIcons(menu, mAct);
    }

    private void refreshItems() {
        postsList.clear();
        listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_PROGRESS);
        new RssTask().execute();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        viewModeUtils.handleSelection(item, new ViewModeUtils.ChangeListener() {
            @Override
            public void modeChanged() {
                listAdapter.notifyDataSetChanged();
            }
        });
        switch (item.getItemId()) {
            case R.id.info:
                //show information about the feed in general in a dialog
                if (rssFeed != null) {
                    String FeedTitle = (rssFeed.getTitle());
                    String FeedDescription = (rssFeed.getDescription());
                    //String FeedPubdate = (myRssFeed.getPubdate()); most times not present
                    String FeedLink = (rssFeed.getLink());

                    AlertDialog.Builder builder = new AlertDialog.Builder(mAct);

                    String titlevalue = getResources().getString(R.string.feed_title_value);
                    String descriptionvalue = getResources().getString(R.string.feed_description_value);
                    String linkvalue = getResources().getString(R.string.feed_link_value);

                    if (FeedLink.equals("")) {
                        builder.setMessage(titlevalue + ": \n" + FeedTitle +
                                "\n\n" + descriptionvalue + ": \n" + FeedDescription);
                    } else {
                        builder.setMessage(titlevalue + ": \n" + FeedTitle +
                                "\n\n" + descriptionvalue + ": \n" + FeedDescription +
                                "\n\n" + linkvalue + ": \n" + FeedLink);
                    }

                    builder.setNegativeButton(getResources().getString(R.string.ok), null)
                            .setCancelable(true);
                    builder.create();
                    builder.show();

                }
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

activity_scrollable_tabs

<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:ads="http://schemas.android.com/tools"
android:id="@+id/htab_maincontent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<com.google.android.material.appbar.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabMode="scrollable"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar2"
        app:tabMode="scrollable"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:layout_scrollFlags="scroll|enterAlways"

        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabMode="scrollable"/>
</com.google.android.material.appbar.AppBarLayout>



<androidx.viewpager.widget.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    app:layout_behavior="@string/appbar_scrolling_view_behavior"



    />

Answer 1

我正在更新我的答案，它解决了你的问题。
我认为您想要实现的是 RssFragment 的可重用性.
您需要添加 RssFragment 的新实例通过将不同的 URL 作为参数传递给您的适配器。
我在您的 RssFragment 类中创建了一个静态方法，因此您可以使用 URL 参数创建一个实例。引用下面的代码:

public class RssFragment extends Fragment {
    // Added argument key for URL
    private static final String ARG_URL = "url_string";

    private RSSFeed rssFeed = null;
    private ArrayList<RSSItem> postsList;
    private RssAdapter listAdapter;
    private ViewModeUtils viewModeUtils;
    private SwipeRefreshLayout swipeRefreshLayout;

    private Activity mAct;
    private RelativeLayout ll;
    private String URL;
    private AdView mAdView;
    private View rootView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ll = (RelativeLayout) inflater.inflate(R.layout.fragment_list_refresh, container, false);
        return ll;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        setHasOptionsMenu(true);

        RecyclerView listView = ll.findViewById(R.id.list);
        postsList = new ArrayList<>();
        listAdapter = new RssAdapter(getContext(), postsList);
        listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_PROGRESS);
        listView.setAdapter(listAdapter);
        listView.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));

        swipeRefreshLayout = ll.findViewById(R.id.swipeRefreshLayout);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refreshItems();
            }
        });
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mAct = getActivity();

        // get URL from arguments
        url = RssFragment.this.getArguments().getString(ARG_URL);
        refreshItems();
    }

    private class RssTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            try {
                // Pass the URL string as parameter to URL class
                URL rssUrl = new URL(URL);
                SAXParserFactory mySAXParserFactory = SAXParserFactory.newInstance();
                SAXParser mySAXParser = mySAXParserFactory.newSAXParser();
                XMLReader myXMLReader = mySAXParser.getXMLReader();
                RSSHandler myRSSHandler = new RSSHandler();
                myXMLReader.setContentHandler(myRSSHandler);
                InputSource myInputSource = new InputSource(rssUrl.openStream());
                myXMLReader.parse(myInputSource);

                rssFeed = myRSSHandler.getFeed();

            } catch (ParserConfigurationException | IOException | SAXException e) {
                Log.printStackTrace(e);
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            if (rssFeed != null) {
                if (rssFeed.getList().size() > 0) {
                    postsList.addAll(rssFeed.getList());
                }

                listAdapter.setHasMore(false);
                listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_LIST);
                swipeRefreshLayout.setRefreshing(false);

            } else {
                String message = null;
                if (!url.startsWith("http"))
                    message = "Debug info: '" + url + "' is most likely not a valid RSS url. Make sure the url entered in your configuration starts with 'http' and verify if it's valid XML using https://validator.w3.org/feed/";
                Helper.noConnection(mAct, message);
                listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_EMPTY);
                swipeRefreshLayout.setRefreshing(false);

            }

            super.onPostExecute(result);
        }

    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.rss_menu, menu);
        viewModeUtils = new ViewModeUtils(getContext(), getClass());
        viewModeUtils.inflateOptionsMenu(menu, inflater);
        ThemeUtils.tintAllIcons(menu, mAct);
    }

    private void refreshItems() {
        postsList.clear();
        listAdapter.setModeAndNotify(InfiniteRecyclerViewAdapter.MODE_PROGRESS);
        new RssTask().execute();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        viewModeUtils.handleSelection(item, new ViewModeUtils.ChangeListener() {
            @Override
            public void modeChanged() {
                listAdapter.notifyDataSetChanged();
            }
        });
        switch (item.getItemId()) {
            case R.id.info:
                //show information about the feed in general in a dialog
                if (rssFeed != null) {
                    String FeedTitle = (rssFeed.getTitle());
                    String FeedDescription = (rssFeed.getDescription());
                   //String FeedPubdate = (myRssFeed.getPubdate()); most times not present
                    String FeedLink = (rssFeed.getLink());

                    AlertDialog.Builder builder = new AlertDialog.Builder(mAct);

                    String titlevalue = getResources().getString(R.string.feed_title_value);
                    String descriptionvalue = getResources().getString(R.string.feed_description_value);
                    String linkvalue = getResources().getString(R.string.feed_link_value);

                    if (FeedLink.equals("")) {
                        builder.setMessage(titlevalue + ": \n" + FeedTitle +
                            "\n\n" + descriptionvalue + ": \n" + FeedDescription);
                    } else {
                        builder.setMessage(titlevalue + ": \n" + FeedTitle +
                            "\n\n" + descriptionvalue + ": \n" + FeedDescription +
                            "\n\n" + linkvalue + ": \n" + FeedLink);
                    }

                
builder.setNegativeButton(getResources().getString(R.string.ok), null)
                        .setCancelable(true);
                    builder.create();
                    builder.show();

                }
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
  }

  // This is the factory to instantiate the RssFragment instance with the url string as arguments
  public static RssFragment newInstance(String url) {
       RssFragment newInstance = new RssFragment();
       Bundle bundle = new Bundle();
       bundle.putString(ARG_URL, URL);
       newInstance.setArguments(bundle);
       return newInstance;
   }
}

现在您可以重复使用 RssFragment您的 ScrollableTabsActivity 中的类(class)而不是像下面的代码那样为每个 URL 字符串创建 fragment 类:

adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "cinema news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");
adapter.addFrag(RssFragment.newInstance("YOUR_URL"), "news");