Question of passing values from the main of the viewfager to the fragment.

The main is currently using the View Pager tab layout toolbar. When you click Search here, you perform the SearchAsyncTask. Then, you want to get a long value from SearchAsyncTask's onPostExecute and send this long value to each tab (fragment) to do another AsyncTask in the fragment. However, I don't know how to send the long value to the fragment in the viewfager even if I look at the links

This is the main code.

searchBtn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        String name = inputName.getText().toString();
        new SearchAsyncTask(name).execute ("URL");
    }
});

toolbar = (Toolbar) findViewById(R.id.searchToolbar);
setSupportActionBar(toolbar);
toolbar.setTitle ("search");

tabLayout = (TabLayout) findViewById(R.id.searchTabLayout);
tabLayout.addTab(tabLayout.newTab().setText("m")"));
tabLayout.addTab(tabLayout.newTab().setText("ㄴ")"));
tabLayout.addTab(tabLayout.newTab().setText("ㄹ")"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

viewPager = (ViewPager) findViewById(R.id.searchViewPager);
SearchViewPagerAdapter adapter = new SearchViewPagerAdapter(getSupportFragmentManager(),tabLayout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
viewPager.setOffscreenPageLimit(3);

tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
    @Override
    public void onTabSelected(TabLayout.Tab tab) {
        viewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(TabLayout.Tab tab) {

    }

    @Override
    public void onTabReselected(TabLayout.Tab tab) {

    }
});

This is the viewfager adapter in the main function. How should I send the long value? <

private class SearchViewPagerAdapter extends FragmentStatePagerAdapter {

    int tabCount;

    public SearchViewPagerAdapter(FragmentManager fm, int tabCount) {
        super(fm);
        this.tabCount = tabCount;
    }

    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:
                return new STab1();
            case 1:
                return new STab2();
            case 2:
                return new STab3();
            default:
                return null;
        }
    }

    public Object instantiateItem(ViewGroup container, int position) {
        Fragment createdFragment = (Fragment) super.instantiateItem(container, position);

        switch (position) {
            case 0:
                sTab1 = (STab1) createdFragment;
                break;
            case 1:
                sTab2 = (STab2) createdFragment;
                break;
            case 2:
                sTab3 = (STab3) createdFragment;
                break;
        }
        return createdFragment;
    }

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

android-viewpager tablayout json android fragment

2022-09-21 19:47

3 Answers

Try the function below. You can access the fragments that correspond to the index of the viewpager.

public Fragment findFragmentByPosition(int position) {
    FragmentPagerAdapter fragmentPagerAdapter = getFragmentPagerAdapter();
    return getSupportFragmentManager().findFragmentByTag(
            "android:switcher:" + getViewPager().getId() + ":"
                    + + fragmentPagerAdapter.getItemId(position));
}

A simple method is

If you use the findFragmentByPosition() function, the code will be written in the following shape.

STab1 fragment = (STab1) findFragmentByPosition(0);
fragment.setXXX(long);

2022-09-21 19:47

Current postExecute

     @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        prd.dismiss();
        try {
            JSONObject parentJsonObject = new JSONObject(result);

            long responseCode = parentJsonObject.getLong("responseCode");

            if(responseCode == 33) {
                long id = parentJsonObject.getLong("id");
                STab3 fragment = (STab3) findFragmentByPosition(2);
                fragment.setLong(id);
                //someMethod(id);
            } } else if(responseCode == 34) {
                Toast.makeText (SearchHwamyun.this, "Nickname does not exist!" and Toast.LENGTH_SHORT).show();
            }

        } } catch (JSONException e) {
            e.printStackTrace();
        }
    }

This is a function created by Maine.

public Fragment findFragmentByPosition(int position) {
    FragmentStatePagerAdapter asdf = adapter;
    return getSupportFragmentManager().findFragmentByTag(
            "android:switcher:" + viewPager.getId() + ":" +
                    asdf.getItem(position));
}

Fragment made a function like this

public long setLong(long asdf) {
    asd = asdf;
    return asd;
}

There is a nullPointerException error in postExecute

2022-09-21 19:47

If you do not need to inherit the FragmentStatePagerAdapter, modify the findFragmentByPosition() function below after changing it to inherit the FragmentPagerAdapter.

public Fragment findFragmentByPosition(int position) {
    return getSupportFragmentManager().findFragmentByTag(
            "android:switcher:" + viewPager.getId() + ":"
                    + + ((FragmentPagerAdapter) viewPager.getAdapter()).getItemId(position));
}

It's the same code as the first one I uploaded. I modified the getViewPager() and getFragmentPagerAdapter() functions to match the code you uploaded.

2022-09-21 19:47

If you have any answers or tips

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