Question

我有navigational drawer和每个抽屉项目的片段。现在，在每个片段下，我们使用FragmentPagerAdapter创建了多个片段。

我有3个抽屉项目 Home ， Group 和 Feedback 。在 Home 下，有2个片段，即 My Profile 和 Logged

所以我为 My Profile 和 Logged 创建了一个可滑动的标签页，这两个片段位于主页项下。现在，我已经在两个片段（ My Profile, Logged ）中进行了一些网络调用，但是如何识别FragmentPagerAdapter上哪个片段处于活动状态？是否可以提前停止适配器创建片段。

HomeFragment

        DrawerModel model = new DrawerModel();
        LoggedFragment loggedFrag = new LoggedFragment();
        loggedFrag.setTargetFragment(loggedFrag, 0);
        model.setFragment(loggedFrag);
        dFragments.add(model);

        model = new DrawerModel();
        model.setDrawerTitle(getString(R.string.profile_tab_title));
        model.setFragment(new ProfileFragment());
        dFragments.add(model);


        Bundle bundle = new Bundle();
        bundle.putSerializable("fragments", dFragments);
        fragment = new DrawerFragment();
        fragment.setArguments(bundle);
        navigateFragment(fragment);

DrawerFragment

public class DrawerFragment extends Fragment {

private FragmentAdapter pagerAdapter;
private ViewPager mViewPager;
private ArrayList<DrawerModel> fList;

@SuppressWarnings("unchecked")
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    fList = (ArrayList<DrawerModel>) getArguments().getSerializable(
            "fragments");

    View v = inflater.inflate(R.layout.swipe_tabs, container, false);

    pagerAdapter = new FragmentAdapter(getChildFragmentManager(), fList);

    mViewPager = (ViewPager) v.findViewById(R.id.pager);
    mViewPager.setAdapter(pagerAdapter);

    return v;
}

}

FragmentAdapter

public class FragmentAdapter extends FragmentStatePagerAdapter {

private int TOTAL_TABS = 0;
private ArrayList<DrawerModel> fragmentList;
private SparseArray<Fragment> mPageReference = new SparseArray<Fragment>();

public FragmentAdapter(FragmentManager fm, ArrayList<DrawerModel> fList) {
    super(fm);
    // TODO Auto-generated constructor stub
    TOTAL_TABS = fList.size();
    fragmentList = fList;

}

@Override
public Fragment getItem(int position) {
    // TODO Auto-generated method stub

    return fragmentList.get(position).getDrawerFragment();
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return TOTAL_TABS;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
    // TODO Auto-generated method stub
    Fragment fragment = (Fragment) super.instantiateItem(container,
            position);
    mPageReference.put(position, fragment);

    Log.d("FragmentAdapter - OnCreate", mPageReference.size() + "");
    return fragment;
}

@Override
public CharSequence getPageTitle(int position) {
    // TODO Auto-generated method stub

    return fragmentList.get(position).getDrawerTitle();
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
    // TODO Auto-generated method stub
    mPageReference.remove(position);

    Log.d("FragmentAdapter - onDestroy", mPageReference.size() + "");

    super.destroyItem(container, position, object);

}

public Fragment getFragment(int key) {
    return mPageReference.get(key);
}

}

Logged Fragment

public class LoggedFragment extends Fragment implements OnClickListener {

TextView tHeader, tEmail, tvPhone;
SharedPreferences sp;
ImageView ivAds;
String bannerUrl = null;
private Handler handler = new Handler();
private static final String TAG = "LoggedFragment";

private void addListeners() {
    // TODO Auto-generated method stub

    ivAds.setOnClickListener(this);

}

Runnable updateImage = new Runnable() {

    @Override
    public void run() {
        // TODO Auto-generated method stub

        if (Utility.checkConnectivity(getActivity()))
            new ImageTask((Home_Activity) getActivity(), "Logged")
                    .execute();

        handler.postDelayed(this, Utility.AD_DURATION);
    }
};

@Override
public void onStart() {
    // TODO Auto-generated method stub
    super.onStart();

    if (handler != null)
        handler.post(updateImage);

}

@Override
public void onStop() {
    // TODO Auto-generated method stub
    super.onStop();

    if (handler != null)
        handler.removeCallbacks(updateImage);

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub

    View v = inflater.inflate(R.layout.logged_in, container, false);

    bindComponents(v);
    addListeners();

    return v;
}

private void bindComponents(View v) {
    // TODO Auto-generated method stub

    ivAds = (ImageView) v.findViewById(R.id.ivLoggedAds);
}

public void updateBanner(Bitmap bitmap, String url) {

    ivAds.setImageBitmap(bitmap);
    bannerUrl = url;
}

}

Call to update fragment method

    Fragment fragment = activity.getSupportFragmentManager()
                    .findFragmentById(R.id.content_frame)
                    .getTargetFragment();

            if (fragment instanceof LoggedFragment) {

                LoggedFragment logged = (LoggedFragment) fragment;
                logged.updateBanner(result, parameter[1]);

            } else
                Log.d(TAG, "No Logged Fragment Found");

现在在记录和我的个人资料片段中我需要动态获取一些数据，因为用户可以看到片段，但无法这样做吗？

非常感谢任何想法/建议。

Answer 1

使用下面的代码找到你的片段，

 FragmentAdapter pa = (FragmentAdapter)viewPager.getAdapter();
 pa.getFragment(viewPager.getCurrentItem()).updateBanner();

代码选择当前可见片段，您可以通过

将其更改为其他片段

 pa.getFragment(index of other fragment).updateBanner();

您必须将pa.getFragment(viewPager.getCurrentItem())投射到您想要的片段，例如，如果在该位置记录它，请将其更改为：

((LoggedFragment)pa.getFragment(viewPager.getCurrentItem()) )

Answer 2

我会说你有两个不同的选择。

选项一：使用setTargetFragment()和getTargetFragment()，以便获得所需片段的引用。

选项二：使用FragmentManager只需从FragmentManager获取所需的片段，然后调用您在片段中定义的方法。

如何从不同的类中访问片段中的方法？

2 个答案: