android - 来回切换选项卡后，ListFragments 无限滚动不起作用

Question

我有一个应用程序，它的主要活动托管由选项卡控制的 2 个列表片段（由 actionbarsherlock 提供）。

两个片段在代码中不太相同，并且从服务器动态加载数据。一个显示最新内容，第二个显示数据库中的所有内容，并实现无限滚动。

如果仅按以下顺序使用，则一切正常：latestFragment -> allFragment

但是当我从 latestFragment 回到 allFragment allFragment -> latestFragment

无尽的滚动停止工作！

我是android开发的新手，研究了一些零碎的东西确实设法把它们放在一起，但它卡在这里。我根本无法绕过。然后无论我做什么滚动都不会工作，直到我关闭应用程序并重新开始。

MainActivity.java

public class MainActivity extends SlidingFragmentActivity implements OnQueryTextListener { protected static DisplayImageOptions options; protected static ImageLoader imageLoader; ArrayList latest; ArrayList generes;



            ActionBar.Tab latestTab;
            ActionBar.Tab AllTab;

            LatestNewsFragment latestNews;
            AllNewsFragment allNews;


            MenuItem search;
            SearchView searchView;
            ProgressBar pBar;
            SharedPreferences settings;

            protected CategoryListFragment mFrag;


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

            pBar = (ProgressBar) this.findViewById(R.id.pBar);
            pBar.setVisibility(View.GONE);

            ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(this.getApplicationContext())
            .build();

            imageLoader = ImageLoader.getInstance();
            imageLoader.init(config);

            options = new DisplayImageOptions.Builder()
            .showStubImage(R.drawable.poster)
            .delayBeforeLoading(2000)
            .showImageForEmptyUri(R.drawable.poster)
            .showImageOnFail(R.drawable.poster)
            .bitmapConfig(Bitmap.Config.RGB_565)
            .imageScaleType(ImageScaleType.NONE)
            .cacheOnDisc()
            .cacheInMemory()
            .build();

            Bundle extras = getIntent().getExtras();
            latest = extras.getParcelableArrayList("latest");
            generes = extras.getParcelableArrayList("generes");
            disclaimer = extras.getString("disclaimer");

            /* Tabs */
            getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

            /* Latest list fragment */
            latestNews = new LatestNewsFragment();
            latestNews.setImagLoader(imageLoader);
            latestNews.setImageDisplayOptions(options);
            latestNews.setData(latest);
            latestTab = getSupportActionBar().newTab().setText("Latest");
            latestTab.setTabListener(new TabListener(latestNews));
            getSupportActionBar().addTab(latestTab);

            /* All news list fragment */
            allNews = new AllNewsFragment();
            allNews.setImagLoader(imageLoader);
            allNews.setImageDisplayOptions(options);
            AllTab = getSupportActionBar().newTab().setText("Browse All");
            AllTab.setTabListener(new TabListener(allNews));
            getSupportActionBar().addTab(AllTab);

            /* Sliding menu */

            // set the Behind View
            setBehindContentView(R.layout.menu_frame);
            if (savedInstanceState == null) {
            FragmentTransaction t = this.getSupportFragmentManager().beginTransaction();
            mFrag = new CategoryListFragment();
            mFrag.setData(generes);
            t.replace(R.id.menu_frame, mFrag);
            t.commit();
            } else {
            mFrag = (CategoryListFragment)this.getSupportFragmentManager().findFragmentById(R.id.menu_frame);
            }

            // customize the SlidingMenu
            SlidingMenu sm = getSlidingMenu();
            sm.setShadowWidthRes(R.dimen.shadow_width);
            sm.setShadowDrawable(R.drawable.shadow);
            sm.setBehindOffsetRes(R.dimen.slidingmenu_offset);
            sm.setFadeDegree(0.35f);
            sm.setTouchModeAbove(SlidingMenu.TOUCHMODE_MARGIN);

            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setDisplayShowTitleEnabled(false);

            settings = getSharedPreferences("com.newsspace.mobile.android", Context.MODE_PRIVATE);
            boolean hasAcceptedPolicy = settings.getBoolean("disclaimeraccept", false);

            if(!hasAcceptedPolicy)
            showDisclaimer(this, disclaimer);
            }

            void showDisclaimer(final Activity context, String message)
            {
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);

            // Setting Dialog Title
            alertDialog.setTitle(getText(R.string.disclaimer));

            // Setting Dialog Message
            alertDialog.setMessage(message);

            // Setting Icon to Dialog
            //alertDialog.setIcon(R.drawable.delete);

            // Setting Positive "Yes" Button
            alertDialog.setPositiveButton(getText(R.string.disclaimer_agree), new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int which) {
            Editor editor = settings.edit();
            editor.putBoolean("disclaimeraccept", true);
            editor.commit();
            }
            });

            // Setting Negative "NO" Button
            alertDialog.setNegativeButton(getText(R.string.disclaimer_disagree), new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
            Editor editor = settings.edit();
            editor.putBoolean("disclaimeraccept", false);
            editor.commit();
            context.finish();
            }
            });

            // Showing Alert Message
            alertDialog.show();
            }

            @Override
            public boolean onCreateOptionsMenu(Menu menu) {
            getSupportMenuInflater().inflate(R.menu.action_menu, menu);
            search = menu.findItem(R.id.search);
            SearchView searchView = (SearchView) search.getActionView();
            searchView.setOnQueryTextListener(this);
            SearchManager searchManager = (SearchManager)getSystemService(Context.SEARCH_SERVICE);
            SearchableInfo info = searchManager.getSearchableInfo(getComponentName());
            searchView.setSearchableInfo(info);

            return true;
            }





            @Override
            public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
            case android.R.id.home:
            toggle();
            return true;

            case R.id.refresh:
            refreshCurrentFragment();
            return true;
            }

            return super.onOptionsItemSelected(item);
            }

            @Override
            public void onItemClick(AdapterView<?> parent, final View view, int position, long id) 
            {
            // NO OP
            }



            void refreshCurrentFragment()
            {

            }




            @Override
            public void hideProgressbar() {
            // TODO Auto-generated method stub
            pBar.setVisibility(View.GONE);
            }


            @Override
            public void showProgressbar() {
            // TODO Auto-generated method stub
            pBar.setVisibility(View.VISIBLE);
            }



            @Override
            public boolean onQueryTextSubmit(String query) {
            // TODO Auto-generated method stub 
            search.collapseActionView();
            return false;
            }



            @Override
            public boolean onQueryTextChange(String newText) {
            // TODO Auto-generated method stub
            return false;
            }


            @Override
            protected void onNewIntent(Intent intent) {
            super.onNewIntent(intent);
            handleIntent(intent);
            }

            private void handleIntent(Intent intent){
            if(Intent.ACTION_SEARCH.equals(intent.getAction())){
            String searchQuery = intent.getStringExtra(SearchManager.QUERY);
            }
            }

            }

TabListener.java

公共类 TabListener 实现 ActionBar.TabListener {

Fragment fragment;

public TabListener(Fragment fragment) {
  this.fragment = fragment;
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    ft.replace(R.id.fragment_container, fragment);
}

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

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

}

AllNewsFragment.java

public class AllNewsFragment extends ListFragment implements OnRefreshListener, OnConnectivityHandler, OnScrollListener {

ArrayList<News> news;
OnNewsSelectedListener listener;
DisplayImageOptions options;
ImageLoader imageLoader;
LazyAdapter adapter;

NewsListQueryData data;
boolean canLoadNewss = true;

int page = 1;
int total = 0;
int category = 0;
String searchterm = "";
View rootview;

int mVisibleThreshold = 5;
int mPreviousTotal = 0;
boolean mLoading = true;
boolean mLastPage = false;

ConnectionManager connectionManager;
boolean isConnected;
boolean failedCall = false;
boolean activityReady = false;



public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootview = inflater.inflate(R.layout.list, null);
    Log.d("APP", "createView");
    return rootview;
}




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




@Override
public void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();
}




public void setImageDisplayOptions(DisplayImageOptions options){
    this.options = options;
}

public void setImagLoader(ImageLoader imageLoader){
    this.imageLoader = imageLoader;
}

public void setData(ArrayList<News> news){
    this.news = news;
}

public ArrayList<News> getData(){
    return this.news;
}

void init()
{
    if(news == null)
    this.news = new ArrayList<News>();

    adapter = new LazyAdapter(news, getActivity(), options, imageLoader);
    setListAdapter(adapter);

    ListView list = (ListView) this.rootview;
    list.setOnScrollListener(this);


    this.category = 0;
    this.page = 1;
    this.searchterm = "";

    this.total = 0;
    this.mPreviousTotal = 0;
    this.mLoading = true;
    this.mLastPage = false;

    connectionManager = new ConnectionManager(this.getActivity(), this);
    isConnected = connectionManager.isConnectedToInternet();
    connectionManager.regsiterForNetworkChanges();

    loadMoreNewss(category, page, searchterm);
}

public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    if(!activityReady) init();
    activityReady = true;
}

@Override
public void onListItemClick(ListView lv, View v, int position, long id) {
    News selectedNews =  (News) getListAdapter().getItem(position);
    if (selectedNews != null)
    showNewsDetails(selectedNews);
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);

    try {
    listener = (OnNewsSelectedListener) activity;
    } catch (ClassCastException e) {
        throw new ClassCastException(activity.toString()
                + " must implement OnHeadlineSelectedListener");
    }


}

void showNewsDetails(News news)
{
    listener.newsSelected(news);
}

@Override
public void result(Object args) {
    listener.hideProgressbar();

    // TODO Auto-generated method stub
    if(args instanceof NewsListQueryData){
    data = (NewsListQueryData) args;
    page = data.page;
    category = data.category;
    searchterm = data.searchterm;
    total = data.total;
    appendData(data.news);
    canLoadNewss = true;
    }
}

@Override
public void fault(Object args) {
    // TODO Auto-generated method stub
    listener.hideProgressbar();
    canLoadNewss = true;
    Toast.makeText(this.getActivity(), R.string.loading_reported_failed, Toast.LENGTH_LONG).show();
}

@Override
public void started(Object args) {
    // TODO Auto-generated method stub
    listener.showProgressbar();
}

@SuppressWarnings("unchecked")
void loadMoreNewss(int category, int page, String searchterm)
{
    if(canLoadNewss){
        if(isConnected){
        new LoadNewsTask(this).execute(Constants.SEARCH_SCRIPT, category, searchterm, page);
        canLoadNewss = false;
        failedCall = false;
        }
        else{
        failedCall = true;
        connectionManager.showProgressDialog();
        }       
    }
}

void appendData(ArrayList<News> news)
{
    for(int i=0;i<news.size();i++)
    adapter.add(news.get(i));
    adapter.notifyDataSetChanged();
}

@Override
public void onScroll(AbsListView view, int firstVisible, int visibleCount, int totalCount) {
    if (mLoading) {
        if (totalCount > mPreviousTotal) {
            mLoading = false;
            mPreviousTotal = totalCount;
            page++;

            // Find your own condition in order to know when you have finished displaying all items
            if (page + 1 > total) {
            mLastPage = true;
            }
        }
    }
    if (!mLastPage && !mLoading && (totalCount - visibleCount) <= (firstVisible + mVisibleThreshold)) {
        loadMoreNewss(category, page, searchterm);
        mLoading = true;
    }
}

@Override
public void onScrollStateChanged(AbsListView arg0, int arg1) {
    // TODO Auto-generated method stub

}

@Override
public void connectToInternet() {
    // TODO Auto-generated method stub

}

@Override
public void doNotConnectToInternet() {
    // TODO Auto-generated method stub

}

@Override
public void connectionStatusChanged() {
    /*
    // TODO Auto-generated method stub
    isConnected = connectionManager.isConnectedToInternet();
    if(isConnected){
    connectionManager.hideProgressDialog();
    if(failedCall) loadMoreNewss(category, page, searchterm);
    }else{
    connectionManager.showProgressDialog();
    }
    */
}

void emptyAdapter()
{
    adapter.clear();
    adapter.notifyDataSetChanged();
}

@Override
public void refresh() 
{
    this.page = 1;
    this.total = 0;
    this.mPreviousTotal = 0;
    this.mLoading = true;
    this.mLastPage = false;

    if(adapter != null) 
    emptyAdapter();

    loadMoreNewss(category, page, searchterm);      
}

}

此外，latestNews Fragment 与 AllNewsFragment 完全相同，只是无限滚动。我可以在这里发帖是需要的。但我觉得这很好。请帮我找到这个问题的答案。

score 0 · Accepted Answer

希望你现在得到你的解决方案。但无论如何，我通过将以下行从init外部if(!activityReady)块移动到onActivityCreated

ListView list = (ListView) this.rootview;
list.setOnScrollListener(this);

android - 来回切换选项卡后，ListFragments 无限滚动不起作用

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