有 TabLayout 和 ViewPager 的嵌套 fragment 。每个 fragment 内部都有 ListView ，因此它们可以一起调用，现在我遇到了应用程序处理速度慢的问题。我尝试了一些解决方案，例如 volley library，但它对我不起作用。有关更多信息，我也发布了我的代码，所以请指导我做到最好。

MainTabFragment.java

public class MainTabFragment extends Fragment {

public static int position_child_tab = 0, three_childs_tab_position = 0;
static int count = -1;
int position_tab = 0;
Bundle args;
MyTabLayout myTabLayout;

public MainTabFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment MainTabFragment.
 */
// TODO: Rename and change types and number of parameters
public static MainTabFragment newInstance(String param1, String param2) {

    return new MainTabFragment();
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.main_tab_fragment, container, false);
    myTabLayout = (MyTabLayout) view.findViewById(R.id.mainTabLayout);
    NonSiwpablePager pager = (NonSiwpablePager) view.findViewById(R.id.pager);
    args = getArguments();
    if (args != null && args.containsKey("pos_next"))
        position_tab = args.getInt("pos_next");
    if (args != null && args.containsKey("pos_end"))
        position_child_tab = args.getInt("pos_end");
    if (position_child_tab != 3) {
        three_childs_tab_position = position_child_tab;
    } else {
        three_childs_tab_position = 0;
    }
    args = new Bundle();
    args.putInt("pos_end", position_child_tab);
    ViewPagerAdapter mAdapter = getViewPagerAdapter();
    pager.setAdapter(mAdapter);
    pager.setOffscreenPageLimit(4);
    myTabLayout.setupWithViewPager(pager);
    for (int i = 0; i < mAdapter.getCount(); i++) {
        View customView = mAdapter.getCustomeView(getActivity(), i);
        myTabLayout.getTabAt(i).setCustomView(customView);
    }
    pager.setCurrentItem(position_tab);
    return view;
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    myTabLayout.getTabAt(position_tab).getCustomView().setSelected(true);
}

private ViewPagerAdapter getViewPagerAdapter() {
    ViewPagerAdapter mAdapter = new ViewPagerAdapter(getChildFragmentManager());
    String title_arr[] = {"ADVISORY", "TOP ADVISORS", "EXPERT VIEW"};
    for (int i = 0; i < title_arr.length; i++) {
        Map<String, Object> map = new Hashtable<>();
        map.put(ViewPagerAdapter.KEY_TITLE, title_arr[i]);
        if (i == 0) {
            map.put(ViewPagerAdapter.KEY_FRAGMENT, AdvisoryPagerFragment.newInstance());
        } else if (i == 1) {
            map.put(ViewPagerAdapter.KEY_FRAGMENT, TopAdvisoryPagerFragment.newInstance());
        } else if (i == 2) {
            map.put(ViewPagerAdapter.KEY_FRAGMENT, ExperViewPagerFragment.newInstance());
        }
        mAdapter.addFragmentAndTitle(map);

    }
    return mAdapter;
}

public static class ViewPagerAdapter extends FragmentStatePagerAdapter {
    private static final String KEY_TITLE = "fragment_title";
    private static final String KEY_FRAGMENT = "fragment";
    boolean abc = false;
    private int[] drawables = new int[]{R.drawable.advisory_selector, R.drawable.top_advisors_selector, R.drawable.expertview_selector};
    private List<Map<String, Object>> maps = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    public View getCustomeView(Context context, int pos) {
        View mView = LayoutInflater.from(context).inflate(R.layout.custom_tab_view, null);
        TextView mTextView = (TextView) mView.findViewById(R.id.textView);
        mTextView.setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/ufonts.com_cambria.ttf"));
        ImageView mImageView = (ImageView) mView.findViewById(R.id.imageView2);
        mImageView.setTag(pos);

        /*if(count >0)
        {
            Toast.makeText(context,"Count Is "+count,Toast.LENGTH_SHORT).show();
            mImageView =  (ImageView) mImageView.getTag(0);
            mImageView.setSelected(false);
        }
        */
        mImageView.setImageResource(drawables[pos]);
        mTextView.setText(getPageTitle(pos));
        return mView;
    }

    public void addFragmentAndTitle(Map<String, Object> map) {
        maps.add(map);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return (CharSequence) maps.get(position).get(KEY_TITLE);
    }

    @Override
    public Fragment getItem(int position) {

        return (Fragment) maps.get(position).get(KEY_FRAGMENT);
    }

    @Override
    public int getCount() {
        return maps.size();
    }
}


}

MainTabFragment 的子 fragment 为:

AdvisoryPagerFragment.java

public class AdvisoryPagerFragment extends Fragment {
static String advisory_child_fragments[];
int myID = 0;
Bundle bundle;
TabLayout mTabLayout;

public AdvisoryPagerFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @return A new instance of fragment AdvisoryPagerFragment.
 */

public static AdvisoryPagerFragment newInstance() {
    return new AdvisoryPagerFragment();
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View inflate = inflater.inflate(R.layout.fragment_app_pager, container, false);
    /*Bundle args = getArguments();
    if (args  != null && args.containsKey("pos_end"))
         myID = args.getInt("pos_end");*/
    myID = MainTabFragment.position_child_tab;
    mTabLayout = (TabLayout) inflate.findViewById(R.id.fragmentTabLayout);
    advisory_child_fragments = new String[]{"EQUITY", "INDICES", "COMMODITY", "CURRENCY"};
    ViewPager pager = (ViewPager) inflate.findViewById(R.id.fragment_pager);
    FragmentViewPagerAdapter mPagerAdapter = new FragmentViewPagerAdapter(getChildFragmentManager());
    pager.setAdapter(mPagerAdapter);
    mTabLayout.setupWithViewPager(pager);
    for (int i = 0; i < mPagerAdapter.getCount(); i++) {
        View customView = mPagerAdapter.getCustomeView(getActivity(), i);
        mTabLayout.getTabAt(i).setCustomView(customView);
    }
    pager.setCurrentItem(myID);
    return inflate;
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    mTabLayout.getTabAt(myID).getCustomView().setSelected(true);
}

public static class FragmentViewPagerAdapter extends FragmentStatePagerAdapter {
    public FragmentViewPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    public View getCustomeView(Context context, int pos) {
        View mView = LayoutInflater.from(context).inflate(R.layout.custom_view, null);
        TextView mTextView = (TextView) mView.findViewById(R.id.belowTab_textview);
        mTextView.setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/ufonts.com_cambria.ttf"));
        mTextView.setText(getPageTitle(pos));
        return mView;
    }

    //
    @Override
    public CharSequence getPageTitle(int position) {
        return advisory_child_fragments[position];
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new EquityFragment();
            case 1:
                return new IndicesFragment();
            case 2:
                return new CommodityFragment();
            case 3:
                return new CurrencyFragment();
        }
        return null;
    }

    @Override
    public int getCount() {
        return 4;
    }
 }
 }

而上述AdvisoryPagerFragment的子 fragment 是

EquityFragment.java

public class EquityFragment extends android.support.v4.app.Fragment implements SearchView.OnQueryTextListener {
public static String imagepath = null;
static ArrayList<EquityDetails> catListDao = new ArrayList<EquityDetails>();
static ArrayList<EquityDetails> catListDao1 = new ArrayList<EquityDetails>();
static int count = 0;
static int count1 = 0;
ListView list;
View view;
Activity act;
AdvisorsAdapter adapter;
TextView empty_text;
private boolean isViewShown = false;
ProgressBar progressBar;

public static EquityFragment newInstance() {
    return new EquityFragment();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.equity_activity, container, false);
    act = this.getActivity();
    Log.d("Callled ", "" + count);
    count++;
    return view;
}

public void onActivityCreated(Bundle savedInstanceState1) {
    super.onActivityCreated(savedInstanceState1);
    if (android.os.Build.VERSION.SDK_INT > 9) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }
    list = (ListView) view.findViewById(R.id.list_equity);
    setHasOptionsMenu(true);
    empty_text = (TextView) view.findViewById(R.id.empty);
    progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
    if (Utils.isNetworkAvailable(getActivity())) {
        if (catListDao.size() > 0) {
            adapter = new AdvisorsAdapter(act, R.layout.custom_equity, catListDao, 5);
            list.setAdapter(adapter);
        } else {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    // do some work here
                    getActivity().runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            //   if (!isViewShown) {
                            new FetchAllData(getActivity(), 5).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
                            //    }
                        }
                    });
                }
            }).start();
        }
    } else {
        CustomToast toast = new CustomToast(getActivity(), "There is no internet connection!");
    }
 }

FetchdataClass 从服务中获取数据并添加到 ListView

public class FetchAllData extends AsyncTask<Void, Void, String> {
    ProgressDialog pDialog;
    int typeId;
    private Context cont;

    public FetchAllData(Context con, int typeId) {
        // TODO Auto-generated constructor stub
        this.cont = con;
        this.typeId = typeId;
        Log.d("Constructor Called", "yes");
    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();

        progressBar.setVisibility(View.VISIBLE);
    }


    @Override
    protected String doInBackground(Void... params) {
        // TODO Auto-generated method stub
        return getString();
    }

    private String getString() {
        // TODO Auto-generated method stub


        URL obj = null;
        HttpURLConnection con = null;
        try {
            obj = new URL(Constants.AppBaseUrl + "/call_listing/" + typeId);
            String userPassword = "oi" + ":" + "kl";
            String header = "Basic " + new String(android.util.Base64.encode(userPassword.getBytes(), android.util.Base64.NO_WRAP));
            con = (HttpURLConnection) obj.openConnection();
            con.addRequestProperty("Authorization", header);
            con.setRequestProperty("Content-type", "application/x-www-form-urlencoded");
            con.setRequestMethod("POST");


            // For POST only - BEGIN
            con.setDoOutput(true);
            OutputStream os = con.getOutputStream();

            os.flush();
            os.close();
            // For POST only - END

            int responseCode = con.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) { //success
                BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
                String inputLine;
                StringBuffer response = new StringBuffer();

                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();
                Log.i("TAG", response.toString());
                return response.toString();


            } else {
                Log.i("TAG", "POST request did not work.");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }


    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);


        if (result != null) {
            //    pDialog.dismiss();
            progressBar.setVisibility(View.GONE);
            JSONObject jsonObject;
            try {
                catListDao = new ArrayList<EquityDetails>();
                jsonObject = new JSONObject(result);
                JSONArray jsonArray = jsonObject.getJSONArray("list");

                Log.d("Length ", "" + jsonArray.length());
                for (int i = 0; i < jsonArray.length(); i++) {
                    EquityDetails allDirectory = new EquityDetails();
                    allDirectory.setEntry_value(jsonArray.getJSONObject(i).getString("entry"));
                    allDirectory.setSerial_value(jsonArray.getJSONObject(i).getString("sl"));
                    allDirectory.setTg_value1(jsonArray.getJSONObject(i).getString("tgt_1"));
                    allDirectory.setTg_value2(jsonArray.getJSONObject(i).getString("tgt_2"));
                    allDirectory.setMainTitle_value(jsonArray.getJSONObject(i).getString("script"));
                    allDirectory.setMain_subTitle_value(jsonArray.getJSONObject(i).getString("exchange"));
                    allDirectory.setRating_value(jsonArray.getJSONObject(i).getString("rating"));
                    allDirectory.setReview_value(jsonArray.getJSONObject(i).getString("review"));
                    allDirectory.setImage1(jsonArray.getJSONObject(i).getString("advisor_image"));
                    allDirectory.setPosted_by(jsonArray.getJSONObject(i).getString("posted_by"));
                    allDirectory.setImage2(jsonArray.getJSONObject(i).getString("script_image"));
                    allDirectory.setCall_id(jsonArray.getJSONObject(i).getString("call_id"));
                    allDirectory.setBuy(jsonArray.getJSONObject(i).getString("buy_sentiment"));
                    allDirectory.setSell(jsonArray.getJSONObject(i).getString("sell_sentiment"));
                    allDirectory.setRecommend(jsonArray.getJSONObject(i).getString("recommendation"));
                    allDirectory.setPosted_date(jsonArray.getJSONObject(i).getString("posted_date"));
                    allDirectory.setExpiry_date(jsonArray.getJSONObject(i).getString("expiry_date"));
                    catListDao.add(allDirectory);
                }
                catListDao1 = catListDao;
                ab = true;
                adapter = new AdvisorsAdapter(act, R.layout.custom_equity, catListDao, 0);
                list.setAdapter(adapter);
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
        //pDialog.dismiss();
        progressBar.setVisibility(View.GONE);

    }


}

最佳答案

尝试设置

pager.setOffscreenPageLimit(no_of_fragments or pages);

在创建 fragment 时在 asyctask 中完成所有任务

关于Android ViewPager 和 TabLayout 运行不快，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34015117/