问题
I have an Fragment with recycleview where I populate it with json items from internet. It load fine and Next step I want to is open new Activity when any row is clicked. It works in activity, thus I modified the same code for fragment but for fragment it throws exception in line
mExampleAdapter.setOnItemClickListener(getActivity());
with errror setOnItemClickListener of refrence adatper cannot be applied to Fragment activty and thus when I change line to
(ExampleAdapter.OnItemClickListener)
and when i build and run . Then app crashes with error that Mainactivity which holds framgnet cannot be cast in to .ExampleAdapter$OnItemClickListener
Here is my whole Fragment class
public class Mynotes extends Fragment implements ExampleAdapter.OnItemClickListener{
public static final String YTD_LINK = "link";
private RecyclerView mRecyclerView;
private ExampleAdapter mExampleAdapter;
private ArrayList<ExampleItem> mExampleList;
private RequestQueue mRequestQueue;
String url="https://api.myjson.com/bins/16mecx";
public Mynotes() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.activity_jsonfeed, container, false);
mRecyclerView = view.findViewById(R.id.recycler_view);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mRecyclerView.addItemDecoration(new MyDividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL, 36));
mExampleList = new ArrayList<>();
mExampleAdapter = new ExampleAdapter(getActivity(), mExampleList);
mRecyclerView.setAdapter(mExampleAdapter);
mExampleAdapter.setOnItemClickListener((ExampleAdapter.OnItemClickListener) getActivity());
parseJSON();
return view;
}
private void parseJSON() {
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
myProgressBar.setVisibility(View.GONE);
try {
JSONArray jsonArray = response.getJSONArray("hits");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject hit = jsonArray.getJSONObject(i);
String videoTitle = hit.getString("title");
String link = hit.getString("link");
mExampleList.add(new ExampleItem(videoTitle, link));
mExampleAdapter.notifyDataSetChanged();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
mRequestQueue.add(request);
}
@Override
public void onItemClick(int position) {
Intent intent = new Intent(getActivity(), NewActiviyt.class);
ExampleItem clickedItem = mExampleList.get(position);
intent.putExtra(YTD_LINK, clickedItem.getmLink());
startActivity(intent);
}
@Override
public void onRefresh() {
}
}
and my Adapter Class is
public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {
private Context mContext;
private ArrayList<ExampleItem> mExampleList;
private OnItemClickListener mListener;
public interface OnItemClickListener {
void onItemClick(int position);
}
public void setOnItemClickListener(OnItemClickListener listener) {
mListener = listener;
}
public ExampleAdapter(Context context, ArrayList<ExampleItem> exampleList) {
mContext = context;
mExampleList = exampleList;
}
@Override
public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(mContext).inflate(R.layout.example_item, parent, false);
return new ExampleViewHolder(v);
}
@Override
public void onBindViewHolder(ExampleViewHolder holder, int position) {
ExampleItem currentItem = mExampleList.get(position);
String title = currentItem.getTitle();
// int likeCount = currentItem.getLikeCount();
// String imageUrl = currentItem.getImageUrl();
holder.mTextViewCreator.setText(title);
// holder.mTextViewLikes.setText("Likes: " + likeCount);
// Glide.with(mContext).load(imageUrl).apply(RequestOptions.circleCropTransform()).into(holder.mImageView);
}
@Override
public int getItemCount() {
return mExampleList.size();
}
public class ExampleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public TextView mTextViewCreator;
// public TextView mTextViewLikes;
// public ImageView mImageView;
public ExampleViewHolder(View itemView) {
super(itemView);
// mTextViewLikes = itemView.findViewById(R.id.text_view_likes);
// mImageView = itemView.findViewById(R.id.image_view);
mTextViewCreator = itemView.findViewById(R.id.text_title);
}
@Override
public void onClick(View view) {
if (mListener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
mListener.onItemClick(position);
}
}
}
}
}
Thanks in advance.
回答1:
replace getActivity with getContext when you work in fragment,
You can read more here
What is different between getContext and getActivity from Fragment in support library?
回答2:
Your activity should implement ExampleAdapter.OnItemClickListener
来源:https://stackoverflow.com/questions/57246997/cannot-cast-onitem-clicklistener-inside-fragment-class-form-adapter-class