android - ViewPager 未使用 FragmentStatePagerAdapter 更新

Question

我有两个 fragment ， fragment A和 fragment B。 fragment A 列出所有产品， fragment B 显示有关产品及其图像的详细信息。

Fragment A 调用 Fragment B 并且 Fragment B 从 Web 服务获取数据并设置为 ViewPager 使用 适配器。最初它显示正确的图像，但此后它始终显示相同的图像。

如果我们从 Fragment B 中的任何点击事件触发 adapter.notifyDataSetChanged() 那么它会完美地工作，但我们必须在 Fragment B 可见时立即显示

请看代码。

 public class ImageAdapter extends FragmentStatePagerAdapter {

private List<String> pImageURL;

public ImageAdapter(FragmentManager fm, List<String> imageURL) {
    super(fm);
    // TODO Auto-generated constructor stub

    pImageURL = imageURL;
    Utility.showLog("PagerAdapter URL", pImageURL.toString());
}

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

    String imageURL = pImageURL.get(position);

    PImageFragment imageFragment = (PImageFragment) PImageFragment.getInstance();
    imageFragment.setProductImage(imageURL);
    return imageFragment;
}

@Override
public int getItemPosition(Object object) {

    PImageFragment pFragment = (PImageFragment) object;
    String URL = pFragment.getProductImage();

    int position = pImageURL.indexOf(URL);

    if (position>=0)
        URL = pImageURL.get(position);

    if (position>=0)
        return position;
    else
        return POSITION_NONE;

}

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

fragment B

   // Image Loading Process

    String p_images = model.getProdutImageURL();

    imageUrl = new ArrayList<String>();


    if (p_images.contains(","))
        imageUrl.addAll(Arrays.asList(p_images.split(",")));
    else
        imageUrl.add(p_images);

    mAdapter = new ImageAdapter(getChildFragmentManager(), imageUrl);
    vPager.setPageTransformer(true, new DepthPageTransformer());
    vPager.setAdapter(mAdapter);

    mAdapter.notifyDataSetChanged();

P图像 fragment

public class PImageFragment extends Fragment {

private static final String TAG = "Product_Images_Fragment";
private View rootView;

private ImageView ivProductImage;
private String imageURL;

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

    rootView = inflater.inflate(R.layout.p_detail_images, container, false);

    bindComponents(rootView);
    loadImages(imageURL);
    return rootView;

}

public static Fragment getInstance() {

    Fragment fragment = new PImageFragment();
    return fragment;
}

public void setProductImage(String image_url) {

    imageURL = image_url;
    Utility.showLog(TAG + "Received URL : ", imageURL.toString());

}

public String getProductImage() {

    return imageURL;
}

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

    ivProductImage = (ImageView) v.findViewById(R.id.ivProductImage);
}

private void loadImages(String image_url) {


    Utility.showLog(TAG,
            "http://baryapp.com/kickzexchange/assets/products/" + image_url);

    final ProgressBar pBar = (ProgressBar) rootView
            .findViewById(R.id.pBarLoader);
    pBar.setVisibility(View.VISIBLE);

    ImageLoader imgLoader = VolleySingleton.getInstance().getImageLoader();

    imgLoader.get("http://baryapp.com/kickzexchange/assets/products/"
            + image_url, new ImageListener() {

        @Override
        public void onErrorResponse(VolleyError vError) {
            // TODO Auto-generated method stub

            Utility.showLog(TAG, vError.getLocalizedMessage() + "");
        }

        @Override
        public void onResponse(ImageContainer response, boolean result) {
            // TODO Auto-generated method stub

            if (response.getBitmap() != null) {

                ivProductImage.setImageBitmap(response.getBitmap());
                pBar.setVisibility(View.GONE);

            }
        }
    });
}


}

更新

    // This is how fragment A calls fragment B
   ProductDetail pDetail = new ProductDetail();

    Bundle bundle = new Bundle();
    bundle.putString("product_id", productList.get(position).getProductID());
    bundle.putString("product_title", productList.get(position).getProductTitle());

    pDetail.setArguments(bundle);

    ((MyTabActivity) mActivity).navigateFragment(Utility.BUY_TAB, pDetail,
            true);

最新更新

    public void navigateFragment(String tag, Fragment fragment,
                             boolean shouldAdd) {

    FragmentManager manager = getSupportFragmentManager();
    FragmentTransaction ft = manager.beginTransaction();


    if (shouldAdd)
        mStacks.get(tag).push(fragment); // push fragment on stack


    if (mCurrentFragment != null) {
        saveFragmentState(mCurrentFragment.getClass().getName(), mCurrentFragment);
    }

    mCurrentFragment = fragment;
    restoreFragmentState(fragment.getClass().getName(), fragment);


    ft.replace(android.R.id.tabcontent, fragment);

    ft.commit();


}

 @Override
protected void onSaveInstanceState(Bundle outState) {
    // TODO Auto-generated method stub
    super.onSaveInstanceState(outState);

    Bundle fragmentStates = new Bundle(mFragmentStates.size());

    for (Map.Entry<String, Fragment.SavedState> entry : mFragmentStates.entrySet()) {
        fragmentStates.putParcelable(entry.getKey(), entry.getValue());
    }
    outState.putParcelable(KEY_FRAGMENT_STATES, fragmentStates);
}


private void saveFragmentState(String id, Fragment fragment) {

    Fragment.SavedState fragmentState =
            getSupportFragmentManager().saveFragmentInstanceState(fragment);
    mFragmentStates.put(id, fragmentState);


}

private void restoreFragmentState(String id, Fragment fragment) {

    Fragment.SavedState fragmentState = mFragmentStates.remove(id);

    if (fragmentState != null) {

        if (!fragment.isAdded())
            fragment.setInitialSavedState(fragmentState);

    }

}

非常感谢任何帮助/想法。

Answer 1

您可以为 fragment 使用以下 PagerFragment 基类，并根据需要实现 onVisible 方法:

public abstract class PagerFragment extends Fragment {

private boolean mCalled = false;
private boolean mWasVisible = false;
private boolean mIsResumed = false;
private boolean mIsPaused = false;

protected void onVisible() {
    mCalled = true;
}

protected void onHide() {
    mCalled = true;
}

/**
 * {@inheritDoc}
 * 
 * @see android.app.Fragment#onAttach(android.app.Activity)
 */
@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

/**
 * {@inheritDoc}
 * 
 * @see android.app.Fragment#onDetach()
 */
@Override
public void onDetach() {
    super.onDetach();
}

/**
 * {@inheritDoc}
 * 
 * @see android.app.Fragment#onResume()
 */
@Override
public void onResume() {
    super.onResume();
    mIsPaused = false;
    mIsResumed = true;
    setUserVisibleHint(getUserVisibleHint());
}

/**
 * {@inheritDoc}
 * 
 * @see android.app.Fragment#onPause()
 */
@Override
public void onPause() {
    mIsPaused = true;
    mIsResumed = false;
    setUserVisibleHint(getUserVisibleHint());
    super.onPause();
}

/**
 * {@inheritDoc}
 * 
 * @see android.app.Fragment#setUserVisibleHint(boolean)
 */
@Override
public void setUserVisibleHint(boolean visible) {
    super.setUserVisibleHint(visible);

    mCalled = false;
    if (mIsResumed) {
        if (visible) {
            performVisible();
            mWasVisible = visible;
        } else {
            performHide();
            mWasVisible = visible;
        }
    } else if (mIsPaused && mWasVisible) {
        performHide();
        mWasVisible = visible;
    }

}

private void performVisible() {
    onVisible();
    if (!mCalled) {
        throw new SuperNotCalledException("PagerFragment " + this + " did not call through to super.onVisible()");
    }
}

private void performHide() {
    onHide();
    if (!mCalled) {
        throw new SuperNotCalledException("PagerFragment " + this + " did not call through to super.onHide()");
    }
}

}

或者您只需在 Fragment A 上预加载数据并在加载数据时通知适配器，然后更改页面。始终可以从 ViewPager 动态添加和删除 Fragment。因此，您也可以尝试删除包含旧数据的 fragment ，然后再创建一个新 fragment 。