I, have implemented image slider using view-pager in my project. Now I want when I click on particular image of the slider. It will open a new Detail Fragment. Where according to that Image Slider information is available. So I tried to implement interface by getting image position using setOnClickListner. But now the problem is I am getting exception when I click on image. and my app gets crashed. Below is my code...
Slider Image Adapter:
public class SliderImageAdapter extends SliderViewAdapter<SliderImageAdapter.SliderAdapterVH>{
public List<Banner> bannerList;
public Context context;
private OnItemClicked onClick;
public interface OnItemClicked {
void onItemClick(int position);
}
public SliderImageAdapter(Context context, List<Banner> bannerList) {
this.bannerList = bannerList;
this.context = context;
}
@Override
public SliderAdapterVH onCreateViewHolder(ViewGroup parent) {
View inflate = LayoutInflater.from(parent.getContext()).inflate(R.layout.image_slider_myshop, parent, false);
return new SliderAdapterVH(inflate);
}
@Override
public void onBindViewHolder(final SliderAdapterVH viewHolder, final int position) {
Glide.with(viewHolder.itemView)
.load(bannerList.get(position).getmSliderImage())
.fitCenter()
.into(viewHolder.imageViewBackground);
viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onClick.onItemClick(position);
}
});
}
@Override
public int getCount() {
return bannerList.size();
}
public int getItemPosition (Object object) {
return POSITION_NONE;
}
public void setOnClick(OnItemClicked onClick) {
this.onClick = onClick;
}
class SliderAdapterVH extends SliderViewAdapter.ViewHolder {
View itemView;
ImageView imageViewBackground;
ImageView imageGifContainer;
public SliderAdapterVH(View itemView) {
super(itemView);
imageViewBackground = itemView.findViewById(R.id.iv_auto_image_slider);
imageGifContainer = itemView.findViewById(R.id.iv_gif_container);
this.itemView = itemView;
}
}
}
Here I am getting the exception in Image Slider Adapter: java.lang.NullPointerException: Attempt to invoke interface method SliderImageAdapter$OnItemClicked.onItemClick(int)' on a null object reference.
@Override
public void onBindViewHolder(final SliderAdapterVH viewHolder, final int position) {
Glide.with(viewHolder.itemView)
.load(bannerList.get(position).getmSliderImage())
.fitCenter()
.into(viewHolder.imageViewBackground);
viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onClick.onItemClick(position);
}
});
}
Home Fragment Code:
public class HomeFragment extends Fragment implements SliderImageAdapter.OnItemClicked {
private SliderImageAdapter sliderImageAdapter;
private List<Banner> bannerList;
bannerList = new ArrayList<>();
sliderImageAdapter = new SliderImageAdapter(getActivity(), bannerList);
sliderMyshop = view.findViewById(R.id.imageSlider);
sliderMyshop.setSliderAdapter(sliderImageAdapter);
sliderMyshop.setIndicatorAnimation(IndicatorAnimations.WORM); //set indicator animation by using SliderLayout.IndicatorAnimations. :WORM or THIN_WORM or COLOR or DROP or FILL or NONE or SCALE or SCALE_DOWN or SLIDE and SWAP!!
sliderMyshop.setSliderTransformAnimation(SliderAnimations.SIMPLETRANSFORMATION);
sliderMyshop.setIndicatorSelectedColor(Color.WHITE);
sliderMyshop.setIndicatorUnselectedColor(Color.GRAY);
sliderMyshop.startAutoCycle();
mFirestore.collection("Banner").orderBy("mSliderImage", Query.Direction.DESCENDING).addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@javax.annotation.Nullable QuerySnapshot documentSnapshots, @javax.annotation.Nullable FirebaseFirestoreException e) {
if (e != null) {
Log.d(TAG, "Error : " + e.getMessage());
}
assert documentSnapshots != null;
for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String doc_id = doc.getDocument().getId();
Banner banner = doc.getDocument().toObject(Banner.class).withDocId(doc_id);
bannerList.add(doc.getNewIndex(), banner);
sliderImageAdapter.notifyDataSetChanged();
} else if (doc.getType() == DocumentChange.Type.MODIFIED) {
String docID = doc.getDocument().getId();
Banner changedModel = doc.getDocument().toObject(Banner.class).withDocId(docID);
if (doc.getOldIndex() == doc.getNewIndex()) {
// Item changed but remained in same position
bannerList.set(doc.getOldIndex(), changedModel);
} else {
// Item changed and changed position
bannerList.remove(doc.getOldIndex());
bannerList.add(doc.getNewIndex(), changedModel);
}
} else if (doc.getType() == DocumentChange.Type.REMOVED) {
// remove
bannerList.remove(doc.getOldIndex());
}
sliderImageAdapter.notifyDataSetChanged();
}
}
});
@Override
public void onItemClick(int position) {
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.fragment_container_dashboard, SliderClickFragment.newInstance(bannerList.get(position).getmSliderImage()));
ft.addToBackStack(null); // this line responsible for adding fragment in backstack.
ft.commit();
}
Detail Fragment Code:
public abstract class SliderClickFragment extends Fragment {
public static Fragment newInstance(String getmSliderImage) {
Bundle args = new Bundle();
HomeFragment fragment = new HomeFragment();
fragment.setArguments(args);
return fragment;
}
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable final Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.slider_click_listner, container, false);
return view;
}
}
