android - 从 MainActivity 的 fragment 中调用函数

Question

编辑
fragment A 具有功能 A1
fragment B 具有功能 B1
主要 Activity 中的两个标签
tabA 得到 fragment A
tabB 得到 fragment B
我的问题是:从主要 Activity 调用函数 A1

 //here i create taps and fragment into viewpaper

 private void setupViewPager(ViewPager viewPager){
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new OneFragment(),"ONE");
    adapter.addFragment(new TwoFragment(),"TWO");
    viewPager.setAdapter(adapter);
}



 class ViewPagerAdapter extends FragmentPagerAdapter{
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();
        @Nullable
        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitleList.get(position);
        }

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

@Override
public Fragment getItem(int position) {
    return mFragmentList.get(position);
}

@Override
public int getCount() {
    return mFragmentList.size();
}
public void addFragment(Fragment fragment,String tittle){
    mFragmentList.add(fragment);
    mFragmentTitleList.add(tittle);
}
 }

Answer 1

根据您发布的代码，您可以像这样将 fragment 的实例直接保存在您的 Activity 中

private OneFragment f1;
private TwoFragment f2;

private void setupViewPager(ViewPager viewPager){
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    f1 = new OneFragment();
    f2 = new TwoFragment();
    adapter.addFragment(f1,"ONE");
    adapter.addFragment(f2,"TWO");
    viewPager.setAdapter(adapter);
}

然后你想在你的 Activity 中的任何地方调用它们就可以了

f1.myMethod();
f2.myMethod();

您也可以只保存您的适配器并使用它来访问 fragment ，如

private ViewPagerAdapter adapter;

private void setupViewPager(ViewPager viewPager){
    adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new OneFragment(),"ONE");
    adapter.addFragment(new TwoFragment(),"TWO");
    viewPager.setAdapter(adapter);
}

并在 Activity 调用中访问它们

OneFragment f1 = (OneFragment)adapter.getItem(0);
TwoFragment f2 = (TwoFragment)adapter.getItem(1);