Android 异步任务不'；t首先在片段中膨胀UI，但当活动恢复或重新启动时，UI膨胀

我正在从事一个项目，该项目从url读取RSS提要，并将其显示在片段活动中。我还使用ViewPager在选项卡中导航，并使用FLipViewController在项目中翻转UI

问题是我在HomeFragment（第一个选项卡屏幕）中使用了一个AsyncTask来读取RSS提要并在HomeFragment UI上显示它们。所有RSS源都已读取，但第一次未在我的HomeFragment UI上显示，但当我使用ViewPager从第一个选项卡导航到最后一个选项卡时，当我的HomeFragment再次启动时，UI会显示活动的源

我在日志里放了一些日志，检查了日志。我开始知道我的onCreateView（）被执行，然后我的AsyncTask被执行，尽管我在onCreate（）方法中编写了AsyncTask，我也尝试在onCreateView（）和onActivityCreated（）方法中使用AsyncTask，但每次都会发生同样的事情

有人能帮我解释为什么当活动第一次启动时，我的异步任务没有执行，为什么当活动重新启动时，UI膨胀而不是第一次。如果可能的话，我还可以通过其他方式实现我所需要的

随信附上我的代码，如有任何帮助，将不胜感激

我的基本活动如下：-

public class Base extends FragmentActivity implements ActionBar.TabListener {

    private ViewPager viewPager;
    private TabPagerAdapter mAdapter;
    private ActionBar actionBar;
    // Tab titles
    private String[] tabs = { "Post", "Category", "Gallery" };

    String TabFragmentHome;

    public void setTabFragmentHome(String t){
        TabFragmentHome = t;
    }

    public String getTabFragmentHome(){
        return TabFragmentHome;
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.base_activity);

        // Initializing...
        viewPager=(ViewPager)findViewById(R.id.pager);
        actionBar=getActionBar();
        mAdapter=new TabPagerAdapter(getFragmentManager());

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

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

        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int arg0) {
                // TODO Auto-generated method stub
                // on changing the page
                // make respected tab selected
                actionBar.setSelectedNavigationItem(arg0);

            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub

            }
        });

        }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.base, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

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

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub

    }   
   }

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="in.advance.Base" />

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/MainLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:clickable="true"
    android:focusable="false" 
    android:background="#ffffff">
    <android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="130dp"
        tools:context="in.advance.Base" />
    <TextView 
        android:id="@+id/tHeadline"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:textColor="#000000"
        android:textSize="22sp"
        android:textStyle="bold"
        android:layout_marginLeft="5sp"
        android:layout_marginRight="5sp"
        android:gravity="left"
        android:typeface="serif"
        android:text="ajdvjka ajk dvajdv ajkl vdjkl "/>

        <LinearLayout 
            android:id="@+id/lLayDateAuthor"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_below="@+id/tHeadline"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="10dp">

            <TextView
                android:id="@+id/tAuthor"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="left"
                android:textColor="#0000ff"
                android:textStyle="italic"
                android:layout_weight="1"
                android:textSize="12sp"
                android:typeface="serif"
                android:text="By: FirstName LastName" />

            <TextView
                android:id="@+id/tDate"
                android:textColor="#0000ff"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="right"
                android:layout_weight="1"
                android:textStyle="italic"
                android:textSize="10sp"
                android:typeface="serif"
                android:text="30/Feb/2020 25:61 Xx" />
        </LinearLayout>

        <ImageView
            android:id="@+id/iStoryImage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_above="@+id/tStoryDetails"
            android:layout_below="@+id/lLayDateAuthor"
            android:layout_gravity="center_horizontal"
            android:scaleType="fitCenter"
            android:src="@drawable/indiacom" />

        <TextView
            android:id="@+id/tStoryDetails"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:maxLines="5"
            android:layout_alignParentBottom="true"
            android:layout_marginBottom="5dp"
            android:gravity="left"
            android:layout_marginLeft="5sp"
            android:layout_marginRight="5sp"
            android:textStyle="normal"
            android:textSize="15sp"
            android:typeface="serif"
            android:text="TextView" /> 

</RelativeLayout>

01-13 16:12:29.155: D/HomeFragment(20997): OnCreate
01-13 16:12:29.155: D/HomeFragment(20997): onCreateView
01-13 16:12:29.160: D/HomeFragment(20997): doInBackground Method
01-13 16:12:29.220: D/Home Fragment(20997): Loading stories started
01-13 16:12:29.325: D/HomeFragment(20997): OnActivityCreated
01-13 16:12:29.325: D/HomeFragment(20997): OnResume
01-13 16:12:31.225: D/AllstoriesParser(20997): AppendCommonListener
01-13 16:12:31.250: D/Author Name:(20997): AFP
01-13 16:12:31.310: D/AllStoriesParser StoryNo:(20997): 1
01-13 16:12:31.310: D/AllStoriesParser list:(20997): Maria Sharapova to spearhead Russia against Poland in Fed Cup
01-13 16:12:31.315: D/Author Name:(20997): Indo-Asian News Service
01-13 16:12:31.400: D/AllStoriesParser Title:(20997): 2
01-13 16:12:31.400: D/AllStoriesParser list:(20997): Goa Minister takes a U-turn after facing flak for controversial remarks over LGBT community

                           || to ||

01-13 16:12:38.910: D/Author Name:(20997): Krishnan Iyer
01-13 16:12:38.915: D/AllStoriesParser Title:(20997): 50
01-13 16:12:38.915: D/AllStoriesParser list:(20997): Cristiano Ronaldo wins FIFA Ballon d’Or 2014: The Award Ceremony – In Pics
01-13 16:12:38.920: D/HomeFragment(20997): OnPostExecute
01-13 16:12:38.950: D/HomeFragment(20997): NoteViewBaseAdapter Started
01-13 16:12:38.965: D/HomeFragment(20997): NoteViewAdapter.getView() Method
01-13 16:12:39.035: W/Settings(20997): Setting airplane_mode_on has moved from android.provider.Settings.System to android.provider.Settings.Global, returning read-only value.
01-13 16:12:39.040: D/HomeFragment(20997): NoteViewAdapter.getView() Method

我的主片段类如下所示：-

public class HomeFragment extends Fragment {

    private static String sAllPostFeedURL = "SOME_FEED_URL";
    List<AllStoriesModel> lASM;
    List<AllStoriesModel>list = new ArrayList<AllStoriesModel>();
    FlipViewController flipview;
    NoteViewBaseAdapter NVBAdapter;

        RelativeLayout rLay;

    @Override
    public View onCreateView(LayoutInflater inflater,
            @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        Log.d("HomeFragment","onCreateView");
        View rootView=inflater.inflate(R.layout.home_fragment, container,false);
        rLay=(RelativeLayout)rootView.findViewById(R.id.MainLayout);

        return flipview;
    }

    @Override
    public void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        Log.d("HomeFragment","OnResume");
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        Log.d("HomeFragment","OnCreate");
        new LoadStoriesOnline().execute();
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        Log.d("HomeFragment","OnActivityCreated");
    }

    public class NoteViewBaseAdapter extends BaseAdapter{

        private final Context mContext = null;
        LayoutInflater inflate;
        List<AllStoriesModel> lstory;

        public NoteViewBaseAdapter(Context homeFragment,
                List<AllStoriesModel> objASM) {
            // TODO Auto-generated constructor stub
            Log.d("HomeFragment","NoteViewBaseAdapter Started");
            inflate=LayoutInflater.from(homeFragment);
            lstory=objASM;
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return lstory.size();
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return position;
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            Log.d("HomeFragment","NoteViewAdapter.getView() Method");
            View layout=convertView;

            if(layout==null){
                layout=inflate.inflate(R.layout.home_fragment, null);
            }
            //Get's value from our ArrayList by the position
            final AllStoriesModel objASM = lstory.get(position);
            TextView tHeadline = (TextView)layout.findViewById(R.id.tHeadline);
            ImageView iStoryImage = (ImageView)layout.findViewById(R.id.iStoryImage);
            TextView tAuthor = (TextView)layout.findViewById(R.id.tAuthor);
            TextView tDate = (TextView)layout.findViewById(R.id.tDate);
            TextView tStoryDesc = (TextView)layout.findViewById(R.id.tStoryDetails);
            RelativeLayout lMore=(RelativeLayout)layout.findViewById(R.id.MainLayout);
            try{
                tHeadline.setText(objASM.getStitle());
                String sStoryDesc="<html><head>" + 
                        "<style type=\"text/css\">" +
                        "</style></head>" +
                "<body>" +
                    "<section id=\"content\">" +
                        objASM.getSdesc() + 
                    "</section>" + "<br><br>"+
                "</body></html>";
                tStoryDesc.setText(Html.fromHtml(sStoryDesc));
                tAuthor.setText(objASM.getSauthor());
                tDate.setText(objASM.getSdate());

                Picasso.with(getActivity())
                .load(objASM.getSthumburl().replace("-150x150.", "."))
                .placeholder(R.drawable.image) // optional
                .error(R.drawable.ic_launcher)         // optional
                .into(iStoryImage);

            }catch(Exception e){
                Log.d("Home Fragment : ", "Error in Feed");
                e.printStackTrace();
            }

            lMore.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    someOperations();
                }
            });

            return layout;
        }

    }

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

        @Override
        protected String doInBackground(String... params) {
            // TODO Auto-generated method stub
            Log.d("HomeFragment","doInBackground Method");
            if(StoryService.checkInternetConnection(getActivity()))
            {
                Log.d("Home Fragment", "Loading stories started");
                HttpGet request = new HttpGet(sAllPostFeedURL);
                request.addHeader("accepts", "application/rss+xml");
                HttpClient client = new DefaultHttpClient();

                HttpResponse response = null;
                try {
                    response = client.execute(request);
                } catch (IOException e) {

                    e.printStackTrace();
                }

                RootElement root = new RootElement("rss");

                lASM = new ArrayList<AllStoriesModel>();
                AllStoriesParser objASP = new AllStoriesParser();

                lASM = AllStoriesParser.appendArrayListener(root.getChild("channel"), 0);

                try {
                    Xml.parse(response.getEntity().getContent(), Xml.Encoding.UTF_8, root.getContentHandler());
                } catch (Exception e) {

                    e.printStackTrace();
                }
            }
            return null;
        }

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            Log.d("HomeFragment","OnPostExecute");
            if(lASM!=null){
                NVBAdapter=new NoteViewBaseAdapter(getActivity(), lASM);
                NVBAdapter.notifyDataSetChanged();
            flipview = new FlipViewController(getActivity(), FlipViewController.VERTICAL);
            flipview.setAdapter(NVBAdapter);

            }
            else{
                Log.d("HomeFragment : ","lASM is null");
            }

        }

    }
}

我的解析器类如下所示：-

public class AllStoriesParser {
    private static AllStoriesModel objASM;
    private String text;

    public AllStoriesParser() {
        // TODO Auto-generated constructor stub
        //lstory = new ArrayList<AllStoriesModel>();
    }

    public static List<AllStoriesModel> appendArrayListener(final Element parent, int depth) {
        final List<AllStoriesModel> lstory = new ArrayList<AllStoriesModel>();
        objASM = new AllStoriesModel();

        Element storyElement = parent.getChild("item");

        storyElement.setEndElementListener(new EndElementListener() {
            @Override
            public void end() {
                lstory.add(objASM.copy());

                Log.d("AllStoriesParser StoryNo:", lstory.size()+"");
                Log.d("AllStoriesParser list:",lstory.get(lstory.size()-1).getStitle()+"");

                }
        });

        appendCommonListeners(storyElement, objASM, depth);

        return lstory;
    }

    private static void appendCommonListeners(Element storyElement,
            final AllStoriesModel objASM, int depth) {
        // TODO Auto-generated method stub
        Log.d("AllstoriesParser","AppendCommonListener");
        storyElement.getChild("guid").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setSguid(body);
                }
            }
        });

        storyElement.getChild("title").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setStitle(body);

                }
            }
        });

        storyElement.getChild("pubDate").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setSdate(body);
                    }
            }
        });

        storyElement.getChild("SOME_VALUE", "creator").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setSauthor("By: "+body);
                    Log.d("Author Name: ", body);
                }
            }
        });

        storyElement.getChild("description").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {

                    objASM.setSdesc(body);
                }
            }
        });

        storyElement.getChild("SOME_VALUE", "encoded").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setScontent(body);
                }
            }
        });

        storyElement.getChild("SOME_VALUE", "thumbnail").setEndTextElementListener(new EndTextElementListener() {
            @Override
            public void end(String body) {
                if (body != null && body != "") {
                    objASM.setSthumburl(body);
                }
            }
        });

    }

}

---

尝试将代码移动到onStart（），这样，当视图可见时，代码将始终运行

在HomeFragment Fragment类的onCreate（）方法中，仍然可以得到相同的结果。当我们第一次通过选项卡导航并返回活动时，UI仍然没有被填充，直到UI被填充。

01-13 16:12:29.155: D/HomeFragment(20997): OnCreate
01-13 16:12:29.155: D/HomeFragment(20997): onCreateView
01-13 16:12:29.160: D/HomeFragment(20997): doInBackground Method
01-13 16:12:29.220: D/Home Fragment(20997): Loading stories started
01-13 16:12:29.325: D/HomeFragment(20997): OnActivityCreated
01-13 16:12:29.325: D/HomeFragment(20997): OnResume
01-13 16:12:31.225: D/AllstoriesParser(20997): AppendCommonListener
01-13 16:12:31.250: D/Author Name:(20997): AFP
01-13 16:12:31.310: D/AllStoriesParser StoryNo:(20997): 1
01-13 16:12:31.310: D/AllStoriesParser list:(20997): Maria Sharapova to spearhead Russia against Poland in Fed Cup
01-13 16:12:31.315: D/Author Name:(20997): Indo-Asian News Service
01-13 16:12:31.400: D/AllStoriesParser Title:(20997): 2
01-13 16:12:31.400: D/AllStoriesParser list:(20997): Goa Minister takes a U-turn after facing flak for controversial remarks over LGBT community

                           || to ||

01-13 16:12:38.910: D/Author Name:(20997): Krishnan Iyer
01-13 16:12:38.915: D/AllStoriesParser Title:(20997): 50
01-13 16:12:38.915: D/AllStoriesParser list:(20997): Cristiano Ronaldo wins FIFA Ballon d’Or 2014: The Award Ceremony – In Pics
01-13 16:12:38.920: D/HomeFragment(20997): OnPostExecute
01-13 16:12:38.950: D/HomeFragment(20997): NoteViewBaseAdapter Started
01-13 16:12:38.965: D/HomeFragment(20997): NoteViewAdapter.getView() Method
01-13 16:12:39.035: W/Settings(20997): Setting airplane_mode_on has moved from android.provider.Settings.System to android.provider.Settings.Global, returning read-only value.
01-13 16:12:39.040: D/HomeFragment(20997): NoteViewAdapter.getView() Method