How to get a context in a recycler view adapter

Question

I m trying to use picasso library to be able to load url to imageView  but I m not able to get the context to use the picasso library correctly   public class FeedAdapter extends RecyclerView Adapter lt FeedAdapter ViewHolder gt        private List lt Post gt  mDataset            Provide a reference to the views for each data item        Complex data items may need more than one view per item  and        you provide access to all the views for a data item in a view holder     public class ViewHolder extends RecyclerView ViewHolder              each data item is just a string in this case         public TextView txtHeader          public ImageView pub image          public ViewHolder View v                super v               txtHeader    TextView  v findViewById R id firstline               pub image    ImageView  v findViewById R id imageView                                Provide a suitable constructor  depends on the kind of dataset      public FeedAdapter List lt Post gt  myDataset            mDataset   myDataset                Create new views  invoked by the layout manager       Override     public FeedAdapter ViewHolder onCreateViewHolder ViewGroup parent                                                     int viewType               create a new view         View v   LayoutInflater from parent getContext    inflate R layout feedholder  parent  false              set the view s size  margins  paddings and layout parameters         ViewHolder vh   new ViewHolder v           return vh                Replace the contents of a view  invoked by the layout manager       Override     public void onBindViewHolder ViewHolder holder  int position               - get element from your dataset at this position            - replace the contents of the view with that element          holder txtHeader setText mDataset get position  getPost text              Picasso with this context  load  http   i imgur com DvpvklR png   into holder pub image                   Return the size of your dataset  invoked by the layout manager       Override     public int getItemCount             return mDataset size

User · Answer

Short answer   Context context    Override public void onAttachedToRecyclerView RecyclerView recyclerView        super onAttachedToRecyclerView recyclerView       context   recyclerView getContext        Explanation why other answers are not great    Passing Context to the adapter is completely unnecessary  since RecyclerView you can access it from inside the class Obtaining Context at ViewHolder level means that you do it every time you bind or create a ViewHolder  You duplicate operations  I don t think you need to worry about any memory leak  If your adapter lingers outside your Activity lifespan  which would be weird  then you already have a leak

User · Answer

you can use this   itemView getContext

User · Answer

If you are using Databinding on layout you can get the context from holder  An exemple below   Override public void onBindViewHolder  NonNull GenericViewHolder holder  int position        View currentView   holder binding getRoot   findViewById R id cycle count manage location line layout     id of your root layout     currentView setBackgroundColor ContextCompat getColor holder binding getRoot   getContext    R color light green

User · Answer

First add a global variable  Context mContext    Then change your constructor to this  public FeedAdapter Context context  List lt Post gt  myDataset        mContext   context      mDataset   myDataset      The pass your context when creating the adapter   FeedAdapter myAdapter   new FeedAdapter this myDataset

User · Answer

You can use like this view getContext    Example  holder tv room name setOnClickListener new View OnClickListener              Override         public void onClick View v                 Toast makeText v getContext        Toast LENGTH SHORT  show

User · Answer

You can add global variable   private Context context    then assign the context from here    Override public FeedAdapter ViewHolder onCreateViewHolder ViewGroup parent int viewType           create a new view     View v LayoutInflater from parent getContext    inflate R layout feedholder  parent  false          set the view s size  margins  paddings and layout parameters     ViewHolder vh   new ViewHolder v          set the Context here      context   parent getContext        return vh      Happy Codding

User · Answer

You have a few options here    Pass Context as an argument to FeedAdapter and keep it as class field Use dependency injection to inject Context when you need it   I strongly suggest reading about it   There is a great tool for that -- Dagger by Square Get it from any View object  In your case this might work for you   holder pub image getContext    As pub image is a ImageView

User · Answer

View mView  mView getContext

User · Answer

Create a constructor of FeedAdapter    Context context    global public FeedAdapter Context context       this context   context        and in Activity   FeedAdapter obj   new FeedAdapter this

User · Answer

First globally declare   Context mContext    pass context with the constructor  by modifying it   public FeedAdapter List lt Post gt  myDataset  Context context        mDataset   myDataset      this mContext   context      then use the mContext whereever you need it

User · Answer

You can use pub image context  holder pub image getContext        Override public void onBindViewHolder ViewHolder ViewHolder  int position         holder txtHeader setText mDataset get position  getPost text          Picasso with holder pub image getContext    load  http   i imgur com DvpvklR png   into holder pub image

User · Answer

You can define   Context ctx     And on onCreate initialise ctx to    ctx parent getContext       Note  Parent is a ViewGroup

[java] How to get a context in a recycler view adapter

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