android - fragment 间调用方法

Question

这是关于 fragment 和 fragment 之间调用方法的非常简单的问题。我已经把代码放在我认为应该调用方法的地方。如果我错了或者您对我的问题有正确的解决方案，请纠正我。 MainFragment 扩展了 Fragment，因为它不是 Activity ...我有抽屉导航，所以它应该是这样...:)

public class MainFragment extends Fragment{

public MainFragment() {
}

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

    adapter = new CategoriesPagerAdapter(getChildFragmentManager(),Titles,Numboftabs);

    pager = (ViewPager) rootView.findViewById(R.id.pager);
    pager.setAdapter(adapter);

    tabs = (SlidingTabLayout) rootView.findViewById(R.id.tabs);
    tabs.setDistributeEvenly(true);
    tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
        @Override
        public int getIndicatorColor(int position) {
            return getResources().getColor(R.color.tabsScrollColor);
        }
    });
    tabs.setViewPager(pager);


    Toolbar mToolbar = (Toolbar) getActivity().findViewById(R.id.toolbar_actionbar);
    final Spinner spinner_nav = (Spinner) mToolbar.findViewById(R.id.spinner_nav);
    spinner_nav.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            // ...here I need to call method "writeText()" in both fragments to update both TextViews also in both fragments (tabs)                
        }
    });     
}

public class CategoriesPagerAdapter extends FragmentStatePagerAdapter {

    CharSequence Titles[];
    int NumbOfTabs;

    public CategoriesPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
        super(fm);
        this.Titles = mTitles;
        this.NumbOfTabs = mNumbOfTabsumb;
    }

    @Override
    public Fragment getItem(int position) {
        if (position == 0) {
            Tab1Class tab1 = new Tab1Class();
            return tab1;
        } else if (position == 1) {
            Tab2Class tab2 = new Tab2Class();
            return tab2;
        } else {
            return null;
        }
    }

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

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

Tab2类:

public class Tab1Class extends Fragment {
TextView tv1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_tab1, container, false);
    tv1 = (TextView) rootView.findViewById(R.id.tv1);
    writeText();
}
public void writeText(){
    tv1.setText("TV1 text");
}
}

Tab1类:

public class Tab2Class extends Fragment {
TextView tv2;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_tab2, container, false);
    tv2 = (TextView) rootView.findViewById(R.id.tv2);
    writeText();
}
public void writeText(){
    tv2.setText("TV2 text");
}
}

Answer 1

.
.
.
Toolbar mToolbar = (Toolbar) getActivity().findViewById(R.id.toolbar_actionbar);
    final Spinner spinner_nav = (Spinner) mToolbar.findViewById(R.id.spinner_nav);
    spinner_nav.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

/////////////////////////Added////////////
adapter.callWrite();
////////////////////////////////////////
        }
    });     
}

public class CategoriesPagerAdapter extends FragmentStatePagerAdapter {

    CharSequence Titles[];
    int NumbOfTabs;
/////////////////////Added///////////////////
Tab1Class tab1;
Tab2Class tab2;
//////////////////////////////

    public CategoriesPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
        super(fm);
        this.Titles = mTitles;
        this.NumbOfTabs = mNumbOfTabsumb;
    }

    @Override
    public Fragment getItem(int position) {
        if (position == 0) {
            tab1 = new Tab1Class();
            return tab1;
        } else if (position == 1) {
            tab2 = new Tab2Class();
            return tab2;
        } else {
            return null;
        }
    }
////////////////////////////Added////////////////////
public void callWrite(){
    if(tab1 != null)
        tab1.writeText();
    if(tab2 != null)
        tab2.writeText();
}
/////////////
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.
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