Question

如今，我对制作没有很多Java和应用程序经验的android应用程序很感兴趣，是的，我是新手。我试图通过流行的应用示例来学习这项工作，所以我选择了一个项目“ Xml Rss Parser” 我发现一些代码特别有效。其解析标题，发布日期，链接并显示在listview上。我相信，我已经了解了代码的工作原理。但我也想获取图像并与Populer android应用等其他人一起显示。

尝试使用JSOUP来获取图像，我搜索了官方站点，这里和很多站点，但是失败了：(我知道只有几行工作得很好，但是我做不到。

我尝试了一些JSOUP代码，通常会收到“空”错误：）描述中的图片链接，开头为（IMG src =），例如本网站rss 在调试屏幕中； Jsoup连接此站点，获取标题，pub_date并再次链接其确定，但获取的图像链接显示为null :)，所以我在某处有一些错误并且不知道。你可以帮帮我吗？

package com.journaldev.androidrssfeedtutorial;

public class RSSFeedActivity extends ListActivity {
    private ProgressBar pDialog;
    ArrayList<HashMap<String, String>> rssItemList = new ArrayList<>();

    RSSParser rssParser = new RSSParser();
    Toolbar toolbar;

    List<RSSItem> rssItems = new ArrayList<>();
    private static String TAG_TITLE = "title";
    private static String TAG_LINK = "link";
    private static String TAG_PUB_DATE = "pubDate";


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_rss_feed);


        String rss_link = getIntent().getStringExtra("rssLink");
        new LoadRSSFeedItems().execute(rss_link);

        ListView lv = getListView();

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                Intent in = new Intent(getApplicationContext(), BrowserActivity.class);
                String page_url = ((TextView) view.findViewById(R.id.page_url)).getText().toString().trim();
                in.putExtra("url", page_url);
                startActivity(in);
            }
        });
    }

    public class LoadRSSFeedItems extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressBar(RSSFeedActivity.this, null, android.R.attr.progressBarStyleLarge);


            RelativeLayout relativeLayout = findViewById(R.id.relativeLayout);
            RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.WRAP_CONTENT,
                    RelativeLayout.LayoutParams.WRAP_CONTENT
            );

            lp.addRule(RelativeLayout.CENTER_IN_PARENT);
            pDialog.setLayoutParams(lp);
            pDialog.setVisibility(View.VISIBLE);
            relativeLayout.addView(pDialog);
        }

        @Override
        protected String doInBackground(String... args) {
            // rss link url
            String rss_url = args[0];

            // list of rss items
            rssItems = rssParser.getRSSFeedItems(rss_url);

            // looping through each item
            for (RSSItem item : rssItems) {
                // creating new HashMap
                if (item.link.toString().equals(""))
                    break;
                HashMap<String, String> map = new HashMap<String, String>();

                // adding each child node to HashMap key => value

                String givenDateString = item.pubdate.trim();
                SimpleDateFormat sdf = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
                try {
                    Date mDate = sdf.parse(givenDateString);
                    SimpleDateFormat sdf2 = new SimpleDateFormat("EEEE, dd MMMM yyyy - hh:mm a", Locale.US);
                    item.pubdate = sdf2.format(mDate);

                } catch (ParseException e) {
                    e.printStackTrace();

                }
                // 
                // I think JSOUP codes should be here, and tried some codes here
                //
                map.put(TAG_TITLE, item.title);
                map.put(TAG_LINK, item.link);
                map.put(TAG_PUB_DATE, item.pubdate); // If you want parse the date

                // adding HashList to ArrayList
                rssItemList.add(map);
            }

            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    ListAdapter adapter = new SimpleAdapter(
                            RSSFeedActivity.this,
                            rssItemList, R.layout.rss_item_list_row,
                            new String[]{TAG_LINK, TAG_TITLE, TAG_PUB_DATE},
                            new int[]{R.id.page_url, R.id.title, R.id.pub_date});

                    // updating listview
                    setListAdapter(adapter);
                }
            });
            return null;
        }

        protected void onPostExecute(String args) {
            pDialog.setVisibility(View.GONE);
        }
    }
}

如何使用JSOUP在rss feed中获取图像？

0 个答案: