如何修复RecyclerView:未连接适配器；跳过布局? [英] How do i fix RecyclerView: No adapter attached; skipping layout?
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问题描述
我已经有一段时间了，但我不断收到错误消息: E/RecyclerView:未连接适配器；跳过布局.
I've been at this for while and i keep getting an error : E/RecyclerView: No adapter attached; skipping layout.
我开始在名为setAdapter的 ViewProfilePostsFragment 中进行更改，但使它无法正常工作.我似乎无法弄清楚为什么会这样.
I started changing things in ViewProfilePostsFragment where the setAdapter is called, i had no success in making it work. I cant seem to figure out why this is happening.
这是我的脚本，所以您可以告诉我我做错了什么，有一个脚本在调用setAdapter方法，另一个在调用RecyclerAdapter脚本.
Here are my scripts so you can tell me what i did wrong, there is the script that's calling the setAdapter method and another for the RecyclerAdapter script.
ViewProfilePostsFragment.java
public class ViewProfilePostsFragment extends Fragment{
private static final String TAG = "ViewProfilePostsFragmen";
private ArrayList<Photo> mPhotos;
private ArrayList<String> mFriends;
private RecyclerView mRecView;
private ViewProfilePostsAdapter mAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_profile_posts, container, false);
mRecView = (RecyclerView) view.findViewById(R.id.lvProfilePosts);
mFriends = new ArrayList<>();
mPhotos = new ArrayList<>();
getFriends();
return view;
}
private void getFriends(){
Log.d(TAG, "getFollowing: searching for FRIENDS **************************************");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(getString(R.string.dbname_friends))
.child(FirebaseAuth.getInstance().getCurrentUser().getUid());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
mFriends.add(singleSnapshot.child(getString(R.string.field_user_id)).getValue().toString());
}
//get the photos
getPhotos();
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getPhotos(){
Log.d(TAG, "getPhotos: getting photos");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
for(int i = 0; i < mFriends.size(); i++){
final int count = i;
Query query = reference
.child(getString(R.string.dbname_user_photos))
.child(mFriends.get(i))
.orderByChild(getString(R.string.field_user_id))
.equalTo(mFriends.get(i));
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Photo photo = new Photo();
Map<String, Object> objectMap = (HashMap<String, Object>) singleSnapshot.getValue();
photo.setCaption(objectMap.get(getString(R.string.field_caption)).toString());
photo.setTags(objectMap.get(getString(R.string.field_tags)).toString());
photo.setPhoto_id(objectMap.get(getString(R.string.field_photo_id)).toString());
photo.setUser_id(objectMap.get(getString(R.string.field_user_id)).toString());
photo.setDate_created(objectMap.get(getString(R.string.field_date_created)).toString());
photo.setImage_path(objectMap.get(getString(R.string.field_image_path)).toString());
mPhotos.add(photo);
}
if(count >= mFriends.size() -1){
//display our photos
displayPhotos();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
private void displayPhotos(){
if(mPhotos != null){
Collections.sort(mPhotos, new Comparator<Photo>() {
@Override
public int compare(Photo o1, Photo o2) {
return o2.getDate_created().compareTo(o1.getDate_created());
}
});
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
mRecView.setLayoutManager(llm);
mAdapter = new ViewProfilePostsAdapter(getActivity(), mPhotos);
mRecView.setAdapter( mAdapter );
}
}
ViewProfilePostsAdapter.java
public class ViewProfilePostsAdapter extends RecyclerView.Adapter<ViewProfilePostsAdapter.ViewHolder> {
private static final String TAG = "CustomAdapter";
//private int[] getItemIn;
private LayoutInflater mInflater;
//private int mLayoutResource;
private Context mContext;
private DatabaseReference mReference;
private String currentUsername;
private ArrayList<Photo> list;
public static class ViewHolder extends RecyclerView.ViewHolder {
//private final TextView textView;
ImageView mProfileImage;
String likesString;
TextView username, timeDelta, caption, likes, liked;
ImageView postImage;
ImageView heartRed, heartWhite;
UserAccountSettings settings = new UserAccountSettings();
User user = new User();
StringBuilder users;
String mLikesString;
boolean likeByCurrentUser;
Heart heart;
GestureDetector detector;
Photo photo;
public ViewHolder(View convertView) {
super(convertView);
username = (TextView) convertView.findViewById(R.id.display_name);
postImage = (ImageView) convertView.findViewById(R.id.post_image);
caption = (TextView) convertView.findViewById(R.id.image_caption);
timeDelta = (TextView) convertView.findViewById(R.id.image_time_posted);
likes = (TextView) convertView.findViewById(R.id.tvLikesString);
mProfileImage = (ImageView) convertView.findViewById(R.id.f_profile_image);
heartRed = (ImageView) convertView.findViewById(R.id.image_heart_red);
heartWhite = (ImageView) convertView.findViewById(R.id.image_heart_white);
heart = new Heart(heartWhite, heartRed);
liked = (TextView) convertView.findViewById(R.id.likeText);
}
}
public ViewProfilePostsAdapter(Context context, ArrayList<Photo> photo) {
this.mContext = context;
this.list = photo;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
// Create a new view.
LayoutInflater mInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = mInflater.inflate(R.layout.layout_post_listitem, null);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(final ViewHolder viewHolder, final int position) {
Log.d(TAG, "Element " + position + " set.");
mReference = FirebaseDatabase.getInstance().getReference();
viewHolder.photo = getItem(position);
viewHolder.detector = new GestureDetector(mContext, new GestureListener(viewHolder));
getCurrentUsername();
getLikesString(viewHolder);
viewHolder.caption.setText(getItem(position).getCaption());
String timestampDifference = getTimestampDifference(getItem(position));
if(!timestampDifference.equals("0")){
viewHolder.timeDelta.setText(timestampDifference + " DAYS AGO");
}else{
viewHolder.timeDelta.setText("TODAY");
}
final ImageLoader imageLoader = ImageLoader.getInstance();
imageLoader.displayImage(getItem(position).getImage_path(), viewHolder.postImage);
//get the profile image and username
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_user_account_settings))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(getItem(position).getUser_id());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.e(TAG, "onDataChange: OnDataChange ******************************************************************************");
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.e(TAG, "onDataChange: found user: "
+ singleSnapshot.getValue(UserAccountSettings.class).getUsername() + "****************************");
viewHolder.username.setText(singleSnapshot.getValue(UserAccountSettings.class).getUsername());
imageLoader.displayImage(singleSnapshot.getValue(UserAccountSettings.class).getProfile_photo(),
viewHolder.mProfileImage);
viewHolder.settings = singleSnapshot.getValue(UserAccountSettings.class);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
Query userQuery = mReference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(getItem(position).getUser_id());
userQuery.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.d(TAG, "onDataChange: found user: " +
singleSnapshot.getValue(User.class).getUsername());
viewHolder.user = singleSnapshot.getValue(User.class);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
@Override
public int getItemCount() {
return list.size();
}
public Photo getItem(int pos){
return list.get(pos);
}
public class GestureListener extends GestureDetector.SimpleOnGestureListener{
ViewHolder mHolder;
public GestureListener(ViewHolder holder) {
mHolder = holder;
}
@Override
public boolean onDown(MotionEvent e) {
return true;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
Log.d(TAG, "onDoubleTap: double tap detected.");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_photos))
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes));
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
String keyID = singleSnapshot.getKey();
//case1: Then user already liked the photo
if(mHolder.likeByCurrentUser &&
singleSnapshot.getValue(Like.class).getUser_id()
.equals(FirebaseAuth.getInstance().getCurrentUser().getUid())){
mReference.child(mContext.getString(R.string.dbname_photos))
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(keyID)
.removeValue();
mReference.child(mContext.getString(R.string.dbname_user_photos))
.child(mHolder.photo.getUser_id())
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(keyID)
.removeValue();
mHolder.heart.toggleLike();
getLikesString(mHolder);
}
//case2: The user has not liked the photo
else if(!mHolder.likeByCurrentUser){
//add new like
addNewLike(mHolder);
break;
}
}
if(!dataSnapshot.exists()){
//add new like
addNewLike(mHolder);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
return true;
}
}
private void addNewLike(final ViewHolder holder){
Log.d(TAG, "addNewLike: adding new like");
String newLikeID = mReference.push().getKey();
Like like = new Like();
like.setUser_id(FirebaseAuth.getInstance().getCurrentUser().getUid());
mReference.child(mContext.getString(R.string.dbname_photos))
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(newLikeID)
.setValue(like);
mReference.child(mContext.getString(R.string.dbname_user_photos))
.child(holder.photo.getUser_id())
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(newLikeID)
.setValue(like);
holder.heart.toggleLike();
getLikesString(holder);
}
private void getCurrentUsername(){
Log.d(TAG, "getCurrentUsername: retrieving user account settings");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(FirebaseAuth.getInstance().getCurrentUser().getUid());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
currentUsername = singleSnapshot.getValue(UserAccountSettings.class).getUsername();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getLikesString(final ViewHolder holder){
Log.d(TAG, "getLikesString: getting likes string");
try{
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_photos))
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes));
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
holder.users = new StringBuilder();
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(singleSnapshot.getValue(Like.class).getUser_id());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.d(TAG, "onDataChange: found like: " +
singleSnapshot.getValue(User.class).getUsername());
holder.users.append(singleSnapshot.getValue(User.class).getUsername());
holder.users.append(",");
}
String[] splitUsers = holder.users.toString().split(",");
if(holder.users.toString().contains(currentUsername + ",")){//mitch, mitchell.tabian
holder.likeByCurrentUser = true;
}else{
holder.likeByCurrentUser = false;
}
int length = splitUsers.length;
if(length == 1){
holder.likesString = "Liked by " + splitUsers[0];
}
else if(length == 2){
holder.likesString = "Liked by " + splitUsers[0]
+ " and " + splitUsers[1];
}
else if(length == 3){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ " and " + splitUsers[2];
}
else if(length == 4){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ ", " + splitUsers[2]
+ " and " + splitUsers[3];
}
else if(length > 4){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ ", " + splitUsers[2]
+ " and " + (splitUsers.length - 3) + " others";
}
Log.d(TAG, "onDataChange: likes string: " + holder.likesString);
//setup likes string
setupLikesString(holder, holder.likesString);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
if(!dataSnapshot.exists()){
holder.likesString = "";
holder.likeByCurrentUser = false;
//setup likes string
setupLikesString(holder, holder.likesString);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}catch (NullPointerException e){
Log.e(TAG, "getLikesString: NullPointerException: " + e.getMessage() );
holder.likesString = "";
holder.likeByCurrentUser = false;
//setup likes string
setupLikesString(holder, holder.likesString);
}
}
private void setupLikesString(final ViewHolder holder, String likesString) {
Log.d(TAG, "setupLikesString: likes string:" + holder.likesString);
if (holder.likeByCurrentUser) {
Log.d(TAG, "setupLikesString: photo is liked by current user");
holder.liked.setText("UnLike");
holder.heartWhite.setVisibility(View.GONE);
holder.heartRed.setVisibility(View.VISIBLE);
holder.heartRed.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return holder.detector.onTouchEvent(event);
}
});
} else {
Log.d(TAG, "setupLikesString: photo is not liked by current user");
holder.liked.setText("Like");
holder.heartWhite.setVisibility(View.VISIBLE);
holder.heartRed.setVisibility(View.GONE);
holder.heartWhite.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return holder.detector.onTouchEvent(event);
}
});
}
holder.likes.setText(likesString);
}
//---------------------------------------------end of likes----------------------------
private String getTimestampDifference(Photo photo){
Log.d(TAG, "getTimestampDifference: getting timestamp difference.");
String difference = "";
Calendar c = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.CANADA);
sdf.setTimeZone(TimeZone.getTimeZone("Canada/Pacific"));//google 'android list of timezones'
Date today = c.getTime();
sdf.format(today);
Date timestamp;
final String photoTimestamp = photo.getDate_created();
try{
timestamp = sdf.parse(photoTimestamp);
difference = String.valueOf(Math.round(((today.getTime() - timestamp.getTime()) / 1000 / 60 / 60 / 24 )));
}catch (ParseException e){
Log.e(TAG, "getTimestampDifference: ParseException: " + e.getMessage() );
difference = "0";
}
return difference;
}
推荐答案
尝试在onCreateView()中设置一个空适配器，并在要更新数据时调用adapter.notifyDataSetChanged.
Try to set an empty adapter in onCreateView() and call adapter.notifyDataSetChanged when you want to update data.
因此，在调用getFriends()的onCreateView()方法中，您应该初始化适配器并将其设置为Recyler视图.
So in your onCreateView() method beore calling getFriends() you should initialise the adapter and set it to recyler view
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_profile_posts, container, false);
mRecView = (RecyclerView) view.findViewById(R.id.lvProfilePosts);
mFriends = new ArrayList<>();
mPhotos = new ArrayList<>();
mAdapter = new ViewProfilePostsAdapter(getActivity(), mPhotos);
mRecView.setAdapter(mAdapter);
getFriends();
return view;
}
然后在displayPhotos()中调用mAdapter.notifyDataSetChanged();
And in your displayPhotos() call mAdapter.notifyDataSetChanged();
private void displayPhotos(){
if(mPhotos != null){
Collections.sort(mPhotos, new Comparator<Photo>() {
@Override
public int compare(Photo o1, Photo o2) {
return o2.getDate_created().compareTo(o1.getDate_created());
}
});
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
mRecView.setLayoutManager(llm);
mAdapter.notifyDataSetChanged();
}
}
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