如何将值从一个片段的回收器视图项传递到另一个片段

Question

我很难理解如何将值从一个片段传递到另一个片段。 I've created a toggle button in recycler item which when checked should pass the content of the card to another fragment(Favourites) implementing recyclerVIew.

这是我的 recyclerView 适配器

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
    private ClipboardManager myClipboard;
    private ClipData myClip;
    private Context context;




    public List<CardItemModel> cardItems;

    public RecyclerAdapter(List<CardItemModel> cardItems){
        this.cardItems = cardItems;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder{
        ImageView copyButton;
        ImageView shareButton;
        ToggleButton favButton;


        TextView title;
        TextView content;
        public ViewHolder(View itemView) {
            super(itemView);
            this.title = (TextView)itemView.findViewById(R.id.card_title);
            this.content = (TextView)itemView.findViewById(R.id.card_content);
            this.copyButton= (ImageView) itemView.findViewById(R.id.copyButton);
            this.shareButton=(ImageView) itemView.findViewById(R.id.shareButton);

            this.favButton=(ToggleButton) itemView.findViewById(R.id.favButton);

            favButton.setChecked(false);
            favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(), R.mipmap.ic_launcher));


        }
    }



    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item,parent,false);
        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.title.setText(cardItems.get(position).title);
        holder.content.setText(cardItems.get(position).content);
        holder.copyButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){


                myClipboard = (ClipboardManager) v.getContext().getSystemService(Context.CLIPBOARD_SERVICE);


                myClip = ClipData.newPlainText("label", holder.content.getText().toString());
                myClipboard.setPrimaryClip(myClip);
                Toast.makeText(v.getContext(), "Copied to clipboard" , Toast.LENGTH_SHORT ).show();

            }
        });
        holder.shareButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                Intent share = new Intent(Intent.ACTION_SEND);
                share.setType("text/plain");
                share.putExtra(Intent.EXTRA_TEXT, holder.content.getText().toString());
                v.getContext().startActivity(Intent.createChooser(share, "Share Text"));
            }
        });

        holder.favButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){
            @Override
            public void onCheckedChanged(CompoundButton favButton, boolean isChecked){
                if (isChecked)
                    favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_launcher));

                else
                    favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(), R.mipmap.ic_cart));
            }
        });
    }

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

这是我想要传递值的“收藏夹”片段。

public class FavouriteFragment extends Fragment {

    private List<CardItemModel> cardItems = new ArrayList<>(20);
    private MainActivity mainActivity;
    private Toolbar toolbar;
    private RecyclerView recyclerView;
    private RecyclerAdapter recyclerAdapter;

    public FavouriteFragment() {

    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        mainActivity = (MainActivity)activity;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_favourite, container, false);

        toolbar = (Toolbar)view.findViewById(R.id.fab_toolbar);

        setupToolbar();



        recyclerView = (RecyclerView)view.findViewById(R.id.fab_recycler_view);

        setupRecyclerView();

        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mainActivity.setupNavigationDrawer(toolbar);
    }

    private void setupToolbar(){
        toolbar.setTitle(getString(R.string.fav_fragment_title));
        mainActivity.setSupportActionBar(toolbar);
    }

    private void setupRecyclerView(){
        recyclerView.setLayoutManager(new LinearLayoutManager(mainActivity));
        recyclerView.setHasFixedSize(true);
        initializeCardItemList();
        recyclerAdapter = new RecyclerAdapter(cardItems);
        recyclerView.setAdapter(recyclerAdapter);
    }

    private void initializeCardItemList(){
        CardItemModel cardItemModel;
        String[] cardTitles = getResources().getStringArray(R.array.fav_cards);
        String[] cardContents = getResources().getStringArray(R.array.fav_cards_content);
        final int length = cardTitles.length;
        for(int i=0;i<length;i++){
            cardItemModel = new CardItemModel(cardTitles[i],cardContents[i]);
            cardItems.add(cardItemModel);
        }
    }



}

Answer 1

您可以为此使用界面。让我们看一个示例，您希望将值从 FragmentA 传递到 FragmentB

    class FragmentA extends Fragment{
     //Your fragment a functionalities goes here
    //now define an interface inside this FragmentA

   //you get reference from main activity
    MainActivity activity;
    @Override
    void onCreate(){
    activity = getActivity();
    }
//after your functionalities you can call passValue function of main activity from the variable 'activity' like
    activity.passValue(your integer value from fragmentA to main activity)

    interface OnValuePassedListener{
      void passValue(int value)//if you want to pass integer value 
      }
    }


    //this is the activity where FragmentA is located

    public class MainActivity extends Activity implements FragmentA.OnValuePassedListener{
//Inside this activity, you write code to open the fragment. When you do that pass this activity's reference to the FragmentA


    @Override
    void passValue(int value){
    //you get the value from FragmentA inside this function
        }

    }

您知道如何将值从活动传递到片段。通过activity内部的passValue()函数，你可以调用另一个fragment并将值传递给fragment。

通过这种方式，您可以使用 Activity 作为中间人将值从 FragmentA 传递到另一个 Fragment。 您可以从这里了解更多信息https://www.youtube.com/watch?v=VyyGP_d0Ia8&index=118&list=PLonJJ3BVjZW6hYgvtkaWvwAVvOFB7fkLa

Answer 2

Fragment之间的通信可以通过EventBus来完成。 脚步 ： 1.创建事件类 2.注册要更改片段数据的事件。 3. 从片段发布事件（点击切换按钮）。

https://github.com/greenrobot/EventBus

http://greenrobot.org/eventbus/

第 1 步：

import java.io.Serializable;

public class ToggleButtonClickEvent implements Serializable {
private CardItemModel cardItemModel;

public ToggleButtonClickEvent (CardItemModel ardItemModel){
    this.cardItemModel= cardItemModel;
}

public CardItemModel getCardItemModel() {
    return cardItemModel;
}

}

第 2 步： 在要更改数据的片段中注册和取消注册事件

 @Override
 public void onStart() {
 super.onStart();
 EventBus.getDefault().register(this);

}

  @Override
  public void onStop() {
     super.onStop();
     EventBus.getDefault().unregister(this);
   }

第 3 步：

点击切换按钮时发布事件

    EventBus.getDefault().post(new ToggleButtonClickEvent(cardItemModel));

Answer 3

在 Bundle 中添加你的值

    Fragment fragment = new Table_Selection_QRCODE();
                            Bundle bun = new Bundle();
                            bun.putString("table","20");
                            fragment.setArguments(bun);
getFragmentManager().beginTransaction().replace(R.id.frag, fragment).commit();

在其他片段中接收这样的值（OnCreate）

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Bundle b=getArguments();
        if(b!=null){
            rslt=b.getString("table","");
        }
    }