我的Rss Reader应用程序无法正常工作，因为解析器太多（Android Studio）？

时间：2016-09-20 11:05:08

标签： android wordpress parsing android-studio xml-parsing

我是一名在韩国杂志上工作的高中生，名为Teen 10 Magazine。作为一个有抱负的计算机科学专业，我决定为我的杂志制作一个RSS阅读器应用程序，以展示我的大学申请技能（以及创建一个应用程序，这一直是我的兴趣）。基本上，我想将我的应用程序格式化为与您的典型新闻应用程序类似（例如CNN，BBC等）。

Category Screen

在DrawerLayout中（如类别屏幕中所示），我决定为每个不同的类别（例如新闻，功能，娱乐等）制作一个标签，包括主页类别，这是文章的类别。根本不重要。当用户单击每个不同的选项卡时，它会为他们提供在该类别下分类的文章列表。为了获得这些数据，我解析数据以获取标题（显示在列表中）和链接（设置为Intent，以便用户可以访问Web中的文章）点击）

然而，虽然有些类别可以使用（家庭，生活方式，时尚），但其余的类别几乎无限期地停留在加载屏幕上。

Example of loading category

我非常确定有效类别的代码和不属于的类别是相同的（供参考，我相应地复制和粘贴并调整了每个不同的类别，也可能是问题，但我不确定），并从相应的网站获取数据。

是否有太多的解析器（RssParser实际解析和七个不同的＆＃34; RssService＆＃34; s使用解析器来解析来自每个不同类别的数据）以供我的应用程序使用？我的应用程序确实偶尔会崩溃......

我将在下面发布我的代码：

MainActivity.java ：

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package com.hfad.teen10magazine;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v7.app.ActionBarDrawerToggle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.ShareActionProvider;
import android.support.v4.widget.DrawerLayout;

public class MainActivity extends Activity {
    /* adds the fragment to the activity */

    private ShareActionProvider shareActionProvider;
    private String[] titles;
    private ListView drawerList;
    private DrawerLayout drawerLayout;
    private ActionBarDrawerToggle drawerToggle;
    private int currentPosition = 0;

    private class DrawerItemClickListener implements ListView.OnItemClickListener {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //Code to run when an item in the navigation drawer gets clicked
            selectItem(position);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        titles = getResources().getStringArray(R.array.titles);
        drawerList = (ListView)findViewById(R.id.drawer);
        drawerLayout = (DrawerLayout)findViewById(R.id.drawer_layout);
        //Initialize the ListView
        drawerList.setAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_activated_1, titles));
        drawerList.setOnItemClickListener(new DrawerItemClickListener());
        //Display the correct fragment.
        if (savedInstanceState != null) {
            currentPosition = savedInstanceState.getInt("position");
            setActionBarTitle(currentPosition);
        } else {
            selectItem(0);

        }
        //Create the ActionBarDrawerToggle
        drawerToggle = new ActionBarDrawerToggle(this, drawerLayout,
                R.string.open_drawer, R.string.close_drawer) {

            //Called when a drawer has settled in a completely closed state
            @Override
            public void onDrawerClosed(View view) {
                super.onDrawerClosed(view);
                invalidateOptionsMenu();
            }

            //Called when a drawer has settled in a completely open state.
            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                invalidateOptionsMenu();
            }
        };
        drawerLayout.addDrawerListener(drawerToggle);
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        getFragmentManager().addOnBackStackChangedListener(
                new FragmentManager.OnBackStackChangedListener() {
                    public void onBackStackChanged() {
                        FragmentManager fragMan = getFragmentManager();
                        Fragment fragment = fragMan.findFragmentByTag("visible_fragment");

                        if (fragment instanceof TopFragment) {
                            currentPosition = 0;
                        }
                        if (fragment instanceof LifestyleFragment) {
                            currentPosition = 1;
                        }
                        if (fragment instanceof EntFragment) {
                            currentPosition = 2;
                        }
                        if (fragment instanceof NewsFragment) {
                            currentPosition = 3;
                        }
                        if (fragment instanceof FeaturesFragment) {
                            currentPosition = 4;
                        }
                        if (fragment instanceof AcademicsFragment) {
                            currentPosition = 5;
                        }
                        if (fragment instanceof FashionFragment) {
                            currentPosition = 6;
                        }
                        setActionBarTitle(currentPosition);
                        drawerList.setItemChecked(currentPosition, true);
                    }
                }
        );
    }

    private void selectItem(int position) {
        // update the main content by replacing fragments
        currentPosition = position;
        Fragment fragment;
        switch(position) {
            case 1:
                fragment = new LifestyleFragment();
                break;
            case 2:
                fragment = new EntFragment();
                break;
            case 3:
                fragment = new NewsFragment();
                break;
            case 4:
                fragment = new FeaturesFragment();
                break;
            case 5:
                fragment = new AcademicsFragment();
                break;
            case 6:
                fragment = new FashionFragment();
                break;
            default:
                fragment = new TopFragment();
        }
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.replace(R.id.fragment_container, fragment, "visible_fragment");
        ft.addToBackStack(null);
        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
        ft.commit();
        //Set the action bar title
        setActionBarTitle(position);
        //Close the drawer
        drawerLayout.closeDrawer(drawerList);
    }
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // If the drawer is open, hide action items related to the content view
        boolean drawerOpen = drawerLayout.isDrawerOpen(drawerList);
        menu.findItem(R.id.action_share).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        drawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        drawerToggle.onConfigurationChanged(newConfig);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("position", currentPosition);
    }

    private void setActionBarTitle(int position) {
        String title="";
        titles=getResources().getStringArray(R.array.titles);
        if (position == 0){
            title = getResources().getString(R.string.app_name);
        } else {
            title = titles[position];
        }
        getActionBar().setTitle(title);
    }

    @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);
        MenuItem menuItem = menu.findItem(R.id.action_share);
        shareActionProvider = (ShareActionProvider) menuItem.getActionProvider();
        setIntent("This is example text");
        return super.onCreateOptionsMenu(menu);
    }

    private void setIntent(String text) {
        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("text/plain");
        intent.putExtra(Intent.EXTRA_TEXT, text);
        shareActionProvider.setShareIntent(intent);
    }
}
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RssItem.java ：

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package com.hfad.teen10magazine;

public class RssItem {

    private final String title;
    private final String link;
    private final String pubDate;

    public RssItem(String title, String link, String pubDate) {
        this.title = title;
        this.link = link;
        this.pubDate = pubDate;
    }

    public String getTitle() {
        return title;
    }

    public String getLink() {
        return link;
    }

    public String getDate() {
        return pubDate;
    }
}
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RssParser.java ：

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package com.hfad.teen10magazine;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.util.Xml;


public class RssParser {
    // We don't use namespaces
    private final String ns = null;

    public List<RssItem> parse(InputStream inputStream) throws XmlPullParserException, IOException {
        try {
            XmlPullParser parser = Xml.newPullParser();
            parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
            parser.setInput(inputStream, null);
            parser.nextTag();
            return readFeed(parser);
        } finally {
            inputStream.close();
        }
    }

    private List<RssItem> readFeed(XmlPullParser parser) throws XmlPullParserException, IOException {
        parser.require(XmlPullParser.START_TAG, null, "rss");
        String title = null;
        String link = null;
        String pubDate = null;

        List<RssItem> items = new ArrayList<RssItem>();
        while (parser.next() != XmlPullParser.END_DOCUMENT) {
            if (parser.getEventType() != XmlPullParser.START_TAG) {
                continue;
            }

            String name = parser.getName();
            if (name.equals("title")) {
                title = readTitle(parser);
            } else if (name.equals("link")) {
                link = readLink(parser);
            } else if (name.equals("pubDate")) {
                pubDate = readDate(parser);
            }

            if (title != null && link != null && pubDate != null) {
                RssItem item = new RssItem(title, link, pubDate);
                items.add(item);
                title = null;
                link = null;
                pubDate = null;
            }
        }
        return items;
    }

    private String readLink(XmlPullParser parser) throws XmlPullParserException, IOException {
        parser.require(XmlPullParser.START_TAG, ns, "link");
        String link = readText(parser);
        parser.require(XmlPullParser.END_TAG, ns, "link");
        return link;
    }

    private String readTitle(XmlPullParser parser) throws XmlPullParserException, IOException {
        parser.require(XmlPullParser.START_TAG, ns, "title");
        String title = readText(parser);
        parser.require(XmlPullParser.END_TAG, ns, "title");
        return title;
    }

    private String readDate(XmlPullParser parser) throws XmlPullParserException, IOException {
        parser.require(XmlPullParser.START_TAG, ns, "pubDate");
        String pubDate = readText(parser);
        parser.require(XmlPullParser.END_TAG, ns, "pubDate");
        return pubDate;
    }

    // For the tags title and link, extract their text values.
    private String readText(XmlPullParser parser) throws IOException, XmlPullParserException {
        String result = "";
        if (parser.next() == XmlPullParser.TEXT) {
            result = parser.getText();
            parser.nextTag();
        }
        return result;
    }
}
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Constants.java ：

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package com.hfad.teen10magazine;


public class Constants {

    public static final String TAG = "Teen10MagazineApp";

}
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RssAdapter.java ：

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package com.hfad.teen10magazine;

import java.util.List;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class RssAdapter extends BaseAdapter {
    /* puts the RSS items in a list */

    private final List<RssItem> items;
    private final Context context;

    public RssAdapter(Context context, List<RssItem> items) {
        this.items = items;
        this.context = context;
    }

    @Override
    public int getCount() {
        return items.size();
    }

    @Override
    public Object getItem(int position) {
        return items.get(position);
    }

    @Override
    public long getItemId(int id) {
        return id;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = View.inflate(context, R.layout.rss_item, null);
            holder = new ViewHolder();
            holder.itemTitle = (TextView) convertView.findViewById(R.id.itemTitle);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.itemTitle.setText(items.get(position).getTitle());
        return convertView;
    }

    static class ViewHolder {
        TextView itemTitle;
    }
}
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除了主要代码之外，为了时间的推移，我将发布一个有效的类别的代码（放置它的片段和用于获取它的RssService）以及不使用的代码。工作。如果您需要更多信息或代码，请与我联系，我很乐意提供信息：

LifeStyleFragment.java （ Works ）：

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package com.hfad.teen10magazine;

import android.app.Fragment;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.ResultReceiver;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;

import java.util.List;


public class LifestyleFragment extends Fragment implements AdapterView.OnItemClickListener {

    private ProgressBar progressBar;
    private ListView listView;
    private View view;

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        if (view == null) {
            view = inflater.inflate(R.layout.fragment_layout, container, false);
            progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
            listView = (ListView) view.findViewById(R.id.listView);
            listView.setOnItemClickListener(this);
            startService();
        } else {
            // If we are returning from a configuration change:
            // "view" is still attached to the previous view hierarchy
            // so we need to remove it and re-attach it to the current one
            ViewGroup parent = (ViewGroup) view.getParent();
            parent.removeView(view);
        }
        return view;
    }

    private void startService() {
        Intent intent = new Intent(getActivity(), RssService_Lifestyle.class);
        intent.putExtra(RssService_Lifestyle.RECEIVER, resultReceiver);
        getActivity().startService(intent);
    }

    private final ResultReceiver resultReceiver = new ResultReceiver(new Handler()) {
        @SuppressWarnings("unchecked")
        @Override
        protected void onReceiveResult(int resultCode, Bundle resultData) {
            List<RssItem> items = (List<RssItem>) resultData.getSerializable(RssService_Lifestyle.ITEMS);
            if (items != null) {
                RssAdapter adapter = new RssAdapter(getActivity(), items);
                listView.setAdapter(adapter);
            } else {
                Toast.makeText(getActivity(), "An error occurred while downloading the rss feed.",
                        Toast.LENGTH_LONG).show();
            }
            progressBar.setVisibility(View.GONE);
            listView.setVisibility(View.VISIBLE);
        };
    };

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        RssAdapter adapter = (RssAdapter) parent.getAdapter();
        RssItem item = (RssItem) adapter.getItem(position);
        Uri uri = Uri.parse(item.getLink());
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        startActivity(intent);
    }
}
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RssService_Lifestyle.java ：

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package com.hfad.teen10magazine;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.net.URL;
import java.util.List;

import org.xmlpull.v1.XmlPullParserException;

import android.app.IntentService;
import android.content.Intent;
import android.os.Bundle;
import android.os.ResultReceiver;
import android.util.Log;

public class RssService_Lifestyle extends IntentService {
    /* parse the rss feed on lifestyle and send the list of items to LifestyleFragment */


    private static final String RSS_LINK = "http://www.teen10mag.com/category/lifestyle/feed/";
    public static final String ITEMS = "items";
    public static final String RECEIVER = "receiver";

    public RssService_Lifestyle() {
        super("RssService_Lifestyle");
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.d(Constants.TAG, "Service started");
        List<RssItem> rssItems = null;
        try {
            RssParser parser = new RssParser();
            rssItems = parser.parse(getInputStream(RSS_LINK));
        } catch (XmlPullParserException | IOException e) {
            Log.w(e.getMessage(), e);
        }
        Bundle bundle = new Bundle();
        bundle.putSerializable(ITEMS, (Serializable) rssItems);
        ResultReceiver receiver = intent.getParcelableExtra(RECEIVER);
        receiver.send(0, bundle);
    }

    public InputStream getInputStream(String link) {
        try {
            URL url = new URL(link);
            return url.openConnection().getInputStream();
        } catch (IOException e) {
            Log.w(Constants.TAG, "Exception while retrieving the input stream", e);
            return null;
        }
    }
}
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AcademicsFragment.java （没有工作）：

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package com.hfad.teen10magazine;

import java.util.List;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.ResultReceiver;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;


public class AcademicsFragment extends Fragment implements AdapterView.OnItemClickListener {

    private ProgressBar progressBar;
    private ListView listView;
    private View view;

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        if (view == null) {
            view = inflater.inflate(R.layout.fragment_layout, container, false);
            progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
            listView = (ListView) view.findViewById(R.id.listView);
            listView.setOnItemClickListener(this);
            startService();
        } else {
            // If we are returning from a configuration change:
            // "view" is still attached to the previous view hierarchy
            // so we need to remove it and re-attach it to the current one
            ViewGroup parent = (ViewGroup) view.getParent();
            parent.removeView(view);
        }
        return view;
    }

    private void startService() {
        Intent intent = new Intent(getActivity(), RssService_Academics.class);
        intent.putExtra(RssService_Academics.RECEIVER, resultReceiver);
        getActivity().startService(intent);
    }

    private final ResultReceiver resultReceiver = new ResultReceiver(new Handler()) {
        @SuppressWarnings("unchecked")
        @Override
        protected void onReceiveResult(int resultCode, Bundle resultData) {
            List<RssItem> items = (List<RssItem>) resultData.getSerializable(RssService_Academics.ITEMS);
            if (items != null) {
                RssAdapter adapter = new RssAdapter(getActivity(), items);
                listView.setAdapter(adapter);
            } else {
                Toast.makeText(getActivity(), "An error occurred while downloading the rss feed.",
                        Toast.LENGTH_LONG).show();
            }
            progressBar.setVisibility(View.GONE);
            listView.setVisibility(View.VISIBLE);
        }
    };

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        RssAdapter adapter = (RssAdapter) parent.getAdapter();
        RssItem item = (RssItem) adapter.getItem(position);
        Uri uri = Uri.parse(item.getLink());
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        startActivity(intent);
    }
}
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RssService_Academics.java ：

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package com.hfad.teen10magazine;

import android.app.IntentService;
import android.content.Intent;
import android.os.Bundle;
import android.os.ResultReceiver;
import android.util.Log;

import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.net.URL;
import java.util.List;

public class RssService_Academics extends IntentService {
    /* parse the rss feed on academics and send the list of items to AcademicsFragment */


    private static final String RSS_LINK = "http://www.teen10mag.com/category/academics/feed/";
    public static final String ITEMS = "items";
    public static final String RECEIVER = "receiver";

    public RssService_Academics() {
        super("RssService_Academics");
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.d(Constants.TAG, "Service started");
        List<RssItem> rssItems = null;
        try {
            RssParser parser = new RssParser();
            rssItems = parser.parse(getInputStream(RSS_LINK));
        } catch (XmlPullParserException | IOException e) {
            Log.w(e.getMessage(), e);
        }
        Bundle bundle = new Bundle();
        bundle.putSerializable(ITEMS, (Serializable) rssItems);
        ResultReceiver receiver = intent.getParcelableExtra(RECEIVER);
        receiver.send(0, bundle);
    }

    public InputStream getInputStream(String link) {
        try {
            URL url = new URL(link);
            return url.openConnection().getInputStream();
        } catch (IOException e) {
            Log.w(Constants.TAG, "Exception while retrieving the input stream", e);
            return null;
        }
    }
}
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这是我的第一个问题，所以我试着尽可能详细。如果我的解释过于冗长，我会道歉。这也是我第一次编写这么广泛的内容，所以请原谅我，如果我似乎犯了业余错误...

提前感谢您的所有帮助!!

[编辑] 当我点击不起作用的类别时，logcat会如下所示：

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09-21 19:29:59.237 1541-1866/system_process W/ActivityManager: Unable to start service Intent { cmp=com.hfad.teen10magazine/.RssService_News (has extras) } U=0: not found
09-21 19:30:13.209 2808-2808/com.hfad.teen10magazine I/Choreographer: Skipped 31 frames!  The application may be doing too much work on its main thread.
09-21 19:30:21.122 2808-2814/com.hfad.teen10magazine W/art: Suspending all threads took: 13.025ms`
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0 个答案:

没有答案
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