getSupportFragmentManager（）。findFragmentByTag

Question

首先我使用了FragmentPagerAdapter，我曾经使用它来获取当前的viewpager，但由于我有两个实现了viewpager的片段，它与其他的冲突，而不是我切换到FragmentStatePagerAdapter解决了冲突，但是当我试图获取当前的viewpager时返回null

getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + viewPager.getCurrentItem())

    SalesReport extends Fragment
      final ViewPager viewPager = (ViewPager) viewGroup.findViewById(R.id.pager);

            TabsPagerAdapter adapter = new TabsPagerAdapter(myContext.getSupportFragmentManager());
            viewPager.setAdapter(adapter);
            TabLayout tabLayout = (TabLayout) viewGroup.findViewById(R.id.sliding_tabs);
            tabLayout.setupWithViewPager(viewPager);
        TextView quantity = (TextView) viewGroup.findViewById(R.id.quantity);
quantity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                quantityBoolean = !quantityBoolean;
                SalesReportList page = (SalesReportList) myContext.getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + viewPager.getCurrentItem());
                ListView listView = (ListView) page.getView().findViewById(R.id.saleslistview);
                SalesReportItemAdapter adapter = (SalesReportItemAdapter) listView.getAdapter();
                adapter.sortquantiy(quantityBoolean);
            }
        });

    TabsPagerAdapter extends FragmentStatePagerAdapter{
     @Override
        public Fragment getItem(int position) {

            return  new SalesReportList().newInstance(position);
        }
    }

    class SalesReportList extends Fragment
     ViewGroup viewGroup = (ViewGroup) inflater.inflate(R.layout.fragment_sales_report_list, container, false);
            ListView listView = (ListView) viewGroup.findViewById(R.id.saleslistview);
            SalesReportItemAdapter listItemAdapter = new SalesReportItemAdapter(this, productType);
            listView.setAdapter(listItemAdapter);


    class SalesReportItemAdapter extends BaseAdapter 

        Fragment context;
        ProductType productType;
        List<Sales> salesList;

        public SalesReportItemAdapter(Fragment salesReportList, ProductType productType) {
            context = salesReportList;
            this.productType = productType;
            salesList = Myenum.INSTANCE.getSalesList(productType);

        }

使用FragmentStatePagerAdapter

返回null

Answer 1

library(reshape2); library(plyr); library(stringr); library(lubridate); 
library(knitr); library(sp); library(rgeos); library(lme4); library(formatR);
library(rgdal); library(ggmap); library(maptools); library(Hmisc); library(raster); 
library(car); library(extrafont); library(openNLP); library(effects); library(psych); 
library(MuMIn); library(GPArotation); library(tuneR); library(gdata); library(xlsx); 
library(combinat); library(stargazer); library(grid); library(scales); library(dplyr); 
library(english); library(repmis); library(pscl); library(testthat); library(broom); 
library(ggplot2); library(geosphere); library(moult); library(GGally); library(pavo); 
library(stringi); library(mgcv); library(gam)

detach(package:car, unload = TRUE)
detach(package:mgcv, unload = TRUE)

if (require("gam", quietly = TRUE)) {
        data(kyphosis)
        g <- gam::gam(Kyphosis ~ s(Age,4) + Number, family = binomial, data = kyphosis)
        tidy(g)
        augment(g)
        glance(g)
}

    Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Warning: namespace ‘mgcv’ is not available and has been replaced
by .GlobalEnv when processing object ‘kyphosis’
Error in `$<-.data.frame`(`*tmp*`, "logLik", value = numeric(0)) : 
  replacement has 0 rows, data has 1