如何在ViewPager programmaticaly中设置TextView的文本？

Question

抱歉，我知道有很多关于这个问题的问题，但我尝试了我找到的所有解决方案但没有成功。 我正在尝试在ViewPager中更改TextView的文本。我将屏幕分为两部分：一部分是ViewPager，另一部分是普通布局。如果我更改了正常布局中的文本，它会毫无问题地更改，但如果我更改ViewPager中的文本，它就不会更改。 我有两个xml布局：自动从Android Studio创建的activity_main和fragment main，在MainActivity的OnCreate中我有 setContentView(R.layout.activity_main)

my Fragment

  public static class PlaceholderFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);

        ImageView imageView = (ImageView) rootView.findViewById(R.id.weathericon);
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 1) {
            rootView = inflater.inflate(R.layout.fragment_main, container, false);
        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 2) {
            rootView = inflater.inflate(R.layout.temperatura_main, container, false);
        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 3) {
            rootView = inflater.inflate(R.layout.precipitazioni_main, container, false);

        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 4) {
            rootView = inflater.inflate(R.layout.vento_main, container, false);
        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 5) {
            rootView = inflater.inflate(R.layout.alba_main, container, false);
        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 6) {
            rootView = inflater.inflate(R.layout.umidita_main, container, false);
        }
        if (getArguments().getInt(ARG_SECTION_NUMBER) == 7) {
            rootView = inflater.inflate(R.layout.pressione_main, container, false);


        }
        return rootView;
    }
}

我的PageAdapter

 public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);

    }


    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).
        return PlaceholderFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 7;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "SECTION 1";
            case 1:
                return "SECTION 2";
            case 2:
                return "SECTION 3";
            case 3:
                return "SECTION 4";
            case 4:
                return "SECTION 5";
            case 5:
                return "SECTION 6";
            case 6:
                return "SECTION 7";
        }

        return null;
    }
}

我尝试以这种方式更改文本，当我有新数据时：

 @Override
        public void success(WeatherResponse weatherResponse, Response response) {
            String forecast = weatherResponse.getCurrently().getSummary();


            LayoutInflater inflater = (LayoutInflater) getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View layout1 = inflater.inflate(R.layout.fragment_main,null);


            forecast1 = (TextView) findViewById(R.id.foredesc1);


            wedesc = (TextView) layout1.findViewById(R.id.weatherdescription); //this is in fragment_main
            city = (TextView) layout1.findViewById(R.id.city);



            wedesc.setText("test"); //the problem is here
            forecast1.setText(forecast);

           /* Fragment frg = null;
            frg = getSupportFragmentManager().findFragmentByTag("container");
            final FragmentTransaction ft = getSupportFragmentManager().beginTransaction();

            ft.detach(frg);
            ft.attach(frg);
            ft.commit();
            */



            mViewPager.getAdapter().notifyDataSetChanged();

我发现如果添加更改文本的唯一方法 setContentView(layout1)

但问题是，通过这种方式，我不再拥有ViewPager和其他布局，只有fragment_main xml中的内容。

我不知道我是否解释得很好但问题出在哪里？