android - 如何离线保存 Parser feed sqlite 数据库?
问题描述
当我离线时,数据应该显示图像应该保存到 sqlite 数据库。我需要离线 rss 提要自动更新我想查看其中的数据。保存 sqlite 数据库。下面是有关如何将其连接到 sqlite 的 rss 提要。如果有人有请帮助我离线显示所有数据所有数据必须保存
import android.app.Activity;
import android.app.AlertDialog;
import android.os.AsyncTask;
import android.os.Bundle;
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 android.widget.RelativeLayout;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
import com.Tamillive.newspaper.util.Helper;
import com.Tamillive.newspaper.util.InfiniteRecyclerViewAdapter;
import com.Tamillive.newspaper.util.Log;
import com.Tamillive.newspaper.util.ThemeUtils;
import com.Tamillive.newspaper.util.ViewModeUtils;
import com.google.android.gms.ads.AdView;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
/**
* This activity is used to display a list of rss items
*/
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);
}
}
}
解决方案
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