Question

我在FragmentActivity中有一个异步任务我正在使用jsoup来获取表格的html到目前为止我发现的是doInBackground（）不起作用，即它没有从网站获取html相同的编码是使用活动，但在片段活动中它不是吗？

public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    new JsoupListView().execute();

    // Initilization
    viewPager = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

    viewPager.setAdapter(mAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        

    // Adding Tabs
    for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }

    /**
     * on swiping the viewpager make respective tab selected
     * */
    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            // on changing the page
            // make respected tab selected
            actionBar.setSelectedNavigationItem(position);
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });


}



@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // on tab selected
    // show respected fragment view
    viewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
// Title AsyncTask
private class JsoupListView extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a progressdialog
        mProgressDialog = new ProgressDialog(MainActivity.this);
        // Set progressdialog title
        mProgressDialog.setTitle("Android Jsoup ListView Tutorial");
        // Set progressdialog message
        mProgressDialog.setMessage("Loading...");
        mProgressDialog.setIndeterminate(false);
        // Show progressdialog
        mProgressDialog.show();
    }


    @Override
    protected Void doInBackground(Void... params) {
        // Create an array
        arraylist = new ArrayList<HashMap<String, String>>();

        try {
            // Connect to the Website URL
            Document doc = Jsoup.connect(url).get();


            for (Element table : doc.select("table[id=Table3]")) {

                // Identify all the table row's(tr)
                for (Element row : table.select("tr:gt(0)")) {
                    HashMap<String, String> map = new HashMap<String, String>();

                    // Identify all the table cell's(td)
                    Elements tds = row.select("td");

                    // Identify all img src's
                    Elements imgSrc = row.select("img[src]");
                    // Get only src from img src
                    String imgSrcStr = imgSrc.attr("src");

                    // Retrive Jsoup Elements
                    // Get the first td
                    map.put("field0", tds.get(0).text());
                    //System.out.println(("check"+tds.get(0).text()));
                    // Get the second td
                    map.put("field1", tds.get(1).text());
                    // Get the third td
                    map.put("field2", tds.get(2).text());
                    // Get the image src links
                    map.put("flag", imgSrcStr);
                    // Set all extracted Jsoup Elements into the array
                    arraylist.add(map);
                }
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    } 
    @Override
    protected void onPostExecute(Void result) {
        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listview);
        // Pass the results into ListViewAdapter.java
        adapter = new ListViewAdapter(MainActivity.this, arraylist);
        // Set the adapter to the ListView
         listview.setAdapter(adapter);


        //listview.setAdapter(adapter);
        // Close the progressdialog
        mProgressDialog.dismiss();
    }
}

该应用程序正在运行但我无法在ListView中看到该站点的数据。
请指出我缺少的内容？

Answer 1

将new JsoupListView().execute();移至onResume()而不是onCreate()。在onCreate，mProgressDialog不会显示。希望这会有所帮助。

FragmentActivity中的异步任务不起作用

1 个答案: