How to pass data from Recyclerview to Fragment

问题:

I have a recyclerView populated in a Fragment and I want to Launch a new Fragment and pass data from the adapter ,I try to use Bundles but it always give a null value this my Adapter Class

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder> {
private LayoutInflater inflater;
private List<Information> mList;
private FragmentCommunication mCommunicator;

public RecyclerAdapter(Context context, List<Information> list,FragmentCommunication communication) {
    inflater = LayoutInflater.from(context);
    mList = list;
    mCommunicator=communication;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = inflater.inflate(R.layout.single_row, parent, false);
    MyViewHolder holder = new MyViewHolder(view,mCommunicator);
    return holder;
}

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {

    final Information current = mList.get(position);
    holder.name.setText(current.name);
    holder.job.setText(current.job);

    FragmentB fragmentB=new FragmentB();
    Bundle bundle=new Bundle();
    bundle.putString("NAME",current.name);
    bundle.putString("JOB",current.job);
    fragmentB.setArguments(bundle);

}

@Override
public int getItemCount() {
    return mList.size();
}

public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    TextView name;
    TextView job;
    FragmentCommunication mComminication;

    public MyViewHolder(View itemView, FragmentCommunication Communicator) {
        super(itemView);
        name = (TextView) itemView.findViewById(R.id.tv_name);
        job = (TextView) itemView.findViewById(R.id.tv_gob);
        mComminication=Communicator;
        name.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        mComminication.respond(getAdapterPosition());
    }
}

and this is my new Fragment that I want to launch

public class FragmentB extends Fragment {
TextView textview;
TextView textView2;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view= inflater.inflate(R.layout.fragment_b,container,false);

    textview= (TextView) view.findViewById(R.id.tv_name);
    textView2= (TextView) view.findViewById(R.id.tv_job);
    return view;
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    Bundle arguments = getArguments();


        if (arguments!=null){
        String name= arguments.get("NAME").toString();
        String job= arguments.get("JOB").toString();
            textview.setText(name);
            textView2.setText(job);}

}

}

this is how I connect Fragment and recyclerview Adapter with interface

public interface FragmentCommunication {
void respond(int position);

}

and this the Fragment where the recyclerview is populated

public class RecyclerViewFragment extends Fragment {
RecyclerView mRecyclerView;
RecyclerAdapter mRecyclerAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view= inflater.inflate(R.layout.recycler_fragment,container,false);

    mRecyclerView= (RecyclerView) view.findViewById(R.id.recycler);
    mRecyclerAdapter=new RecyclerAdapter(getActivity(),getData(),communication);
    mRecyclerView.setAdapter(mRecyclerAdapter);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

    return view;
}

public static List<Information> getData() {
    List<Information>data=new ArrayList<>();
    String[] names={"ahmed","mohammed"};
    String[] jobs={"sacsd","csscs"};

    for (int i=0;i<names.length;i++){
        Information current=new Information();
        current.name=(names[i]);
        current.job=(jobs[i]);
        data.add(current);
    }
    return data;
}

FragmentCommunication communication=new FragmentCommunication() {
    @Override
    public void respond(int position) {
        FragmentB fragmentB=new FragmentB();
        FragmentManager manager=getFragmentManager();
        FragmentTransaction transaction=manager.beginTransaction();
        transaction.replace(R.id.dumper,fragmentB).commit();
    }

};

}

and my mainActivity class is just add the RecyclerViewFragment

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    RecyclerViewFragment fragment=new RecyclerViewFragment();
    FragmentManager manager=getSupportFragmentManager();
    FragmentTransaction transaction=manager.beginTransaction();
    transaction.add(R.id.dumper,fragment).commit();
}

}

so what is the right way to launch fragmentB and pass the data from recyclerview Adapter to fragmentB

回答1:

thank you guys for the answer,I solved the problem using an interface with String values to connect the adapter with the fragment that contains the recyclerview and the other fragment here is what I did exactly : this is the interface

public interface FragmentCommunication {
void respond(int position,String name,String job);

}

and this is the adapter

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder> {
private LayoutInflater inflater;
private List<Information> mList;
private FragmentCommunication mCommunicator;

public RecyclerAdapter(Context context, List<Information> list,FragmentCommunication communication) {
    inflater = LayoutInflater.from(context);
    mList = list;
    mCommunicator=communication;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = inflater.inflate(R.layout.single_row, parent, false);
    MyViewHolder holder = new MyViewHolder(view,mCommunicator);
    return holder;
}

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {

    final Information current = mList.get(position);
    holder.name.setText(current.name);
    holder.job.setText(current.job);

    FragmentB fragmentB=new FragmentB();
    Bundle bundle=new Bundle();
    bundle.putString("NAME",current.name);
    bundle.putString("JOB",current.job);
    fragmentB.setArguments(bundle);

}

@Override
public int getItemCount() {
    return mList.size();
}

public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    TextView name;
    TextView job;
    FragmentCommunication mComminication;

    public MyViewHolder(View itemView, FragmentCommunication Communicator) {
        super(itemView);
        name = (TextView) itemView.findViewById(R.id.tv_name);
        job = (TextView) itemView.findViewById(R.id.tv_gob);
        mComminication=Communicator;
        name.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        mComminication.respond(getAdapterPosition(),mList.get(getAdapterPosition()).name,mList.get(getAdapterPosition()).job);
    }
}

}

the fragment that contains the recyclerview

public class RecyclerViewFragment extends Fragment {
RecyclerView mRecyclerView;
RecyclerAdapter mRecyclerAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view= inflater.inflate(R.layout.recycler_fragment,container,false);

    mRecyclerView= (RecyclerView) view.findViewById(R.id.recycler);
    mRecyclerAdapter=new RecyclerAdapter(getActivity(),getData(),communication);
    mRecyclerView.setAdapter(mRecyclerAdapter);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

    return view;
}

public static List<Information> getData() {
    List<Information>data=new ArrayList<>();
    String[] names={"ahmed","mohammed"};
    String[] jobs={"sacsd","csscs"};

    for (int i=0;i<names.length;i++){
        Information current=new Information();
        current.name=(names[i]);
        current.job=(jobs[i]);
        data.add(current);
    }
    return data;
}

FragmentCommunication communication=new FragmentCommunication() {
    @Override
    public void respond(int position,String name,String job) {
        FragmentB fragmentB=new FragmentB();
        Bundle bundle=new Bundle();
        bundle.putString("NAME",name);
        bundle.putString("JOB",job);
        fragmentB.setArguments(bundle);
        FragmentManager manager=getFragmentManager();
        FragmentTransaction transaction=manager.beginTransaction();
        transaction.replace(R.id.dumper,fragmentB).commit();
    }

};

}

this is the fragmentB where I get the Strings from the Adapter

public class FragmentB extends Fragment {
TextView textview;
TextView textview2;
String name;
String job;

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    name=getArguments().getString("NAME");
    job=getArguments().getString("JOB");

}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view= inflater.inflate(R.layout.fragment_b,container,false);

    textview= (TextView) view.findViewById(R.id.getName);
    textview2= (TextView) view.findViewById(R.id.getJob);
    textview.setText(name);
    textview2.setText(job);


    return view;

}

}

回答2:

Either creating a listener interface in the adapter or using regular old getters, if I understand your question correctly.

回答3:

You need to pass the Bundle to the fragment through the setArguments(Bundle args) method. Since you have not set arguments, the bundle you try to extract in your Fragment resolves to null.

回答4:

You have the right idea with using a Bundle. You just need to pass it to the Fragment by calling setArguments(). Then you retrieve the Bundle in your Fragment with getArguments().

Note that instead of mList.get(position).name, you can do current.name. Similarly for job.

Another part of the problem is that you create FragmentB on two different places. In one place you also call setArguments() but do not show the fragment. In the other you show the fragment but do not call setArguments(). If you really need to do this from multiple parts of your code you should write a method to avoid these inconsistencies.

回答5:

If you are working with kotlin, the solution is much simpler. Original Answer here

pass the lamda val itemClick: (Int) -> Unit to your adapter.

class MyRecyclerViewAdapter(params , val itemClick: (Int) -> Unit): RecyclerView.Adapter<RecyclerView.ViewHolder>() {
internal inner class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {
    ...
    itemView.setOnClickListener( {itemClick(layoutPosition)} )
  } 
}  

In your fragment use the returned value position

val myAdapter = MyRecyclerViewAdapter(params) { position ->
    // do something
}