从适配器中单击时，如何在 RecyclerView 中获取选定位置？

Question

我正在开发一个应用程序，我希望它滚动到我从一个适配器单击到另一个的特定位置 activity 就像 Instagram 检查配置文件片段中的较小图片并滚动到在另一个 activity 中的确切位置，即从小图到大图。

我的适配器代码

public class DisplayDuetAdapter extends RecyclerView.Adapter<DisplayDuetAdapter.ImageViewHolder> {

    private Context mContext;
    private List<DisplayDuet> mDisplayDuet;

    public int position;

    public int getPosition() {
        return position;
    }

    public void setPosition(int position) {
        this.position = position;
    }

    public DisplayDuetAdapter(Context context, List<DisplayDuet> displayDuet){
        mContext = context;
        mDisplayDuet = displayDuet;
    }

    @NonNull
    @Override
    public DisplayDuetAdapter.ImageViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.duet_display_item, viewGroup, false);
        return new DisplayDuetAdapter.ImageViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull final DisplayDuetAdapter.ImageViewHolder imageViewHolder, int i) {

        final DisplayDuet displayDuet = mDisplayDuet.get(i);

        //  Glide.with(mContext).load(displayDuet.getOriginalpics()).into(imageViewHolder.original_pic);

        Picasso.get().load(displayDuet.getOriginalpics()).networkPolicy(NetworkPolicy.OFFLINE).placeholder(R.drawable.placeholder).into(imageViewHolder.original_pic, new Callback() {
            @Override
            public void onSuccess() {

            }

            @Override
            public void onError(Exception e) {
                Picasso.get().load(displayDuet.getOriginalpics()).placeholder(R.drawable.placeholder).into(imageViewHolder.original_pic);

            }
        });

        //   Glide.with(mContext).load(displayDuet.getPostimage()).into(imageViewHolder.post_pic);


        Picasso.get().load(displayDuet.getPostimage()).networkPolicy(NetworkPolicy.OFFLINE).placeholder(R.drawable.placeholder).into(imageViewHolder.post_pic, new Callback() {
            @Override
            public void onSuccess() {

            }

            @Override
            public void onError(Exception e) {
                Picasso.get().load(displayDuet.getPostimage()).placeholder(R.drawable.placeholder).into(imageViewHolder.post_pic);

            }
        });

        imageViewHolder.setiItemClickListener(new IItemClickListener() {
            @Override
            public void onItemClickListener(View view, int position) {
                Intent intent = new Intent(mContext, DuetDisplayActivity.class);
                intent.putExtra("postid", displayDuet.getPostid());
                intent.putExtra("publisherid", displayDuet.getPublisher());
                intent.putExtra("postduetid", displayDuet.getPostduetid());
                mContext.startActivity(intent);
            }
        });



    }

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

    public class ImageViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        public ImageView post_pic, original_pic;

        IItemClickListener iItemClickListener;

        public void setiItemClickListener(IItemClickListener iItemClickListener) {
            this.iItemClickListener = iItemClickListener;
        }

        public ImageViewHolder(@NonNull View itemView) {
            super(itemView);

            post_pic = itemView.findViewById(R.id.duet_pic_one);

            original_pic = itemView.findViewById(R.id.duet_pic_two);

            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            iItemClickListener.onItemClickListener(view, getAdapterPosition());
        }
    }
}

另一个activity代码：

public class DuetDisplayActivity extends AppCompatActivity {

    private String postid, publisher, postduetid;

    private ImageView duet_close;

    int position = 2;

    private RecyclerView duet_show_recyclerView;
    private DuetShowAdapter postAdapter;
    private List<DisplayDuet> postList;

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

        Intent intent = getIntent();
        postid = intent.getStringExtra("postid");
        publisher = intent.getStringExtra("publisherid");
        postduetid = intent.getStringExtra("postduetid");

        duet_close = findViewById(R.id.close);

        duet_show_recyclerView = findViewById(R.id.duet_show_recyclerView);
        duet_show_recyclerView.setHasFixedSize(true);
        LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
        duet_show_recyclerView.setLayoutManager(mLayoutManager);
        postList = new ArrayList<>();
        postAdapter = new DuetShowAdapter(this, postList);
        duet_show_recyclerView.findViewHolderForAdapterPosition(position);
        duet_show_recyclerView.setAdapter(postAdapter);
        SnapHelper startSnapHelper = new PagerSnapHelper();
        duet_show_recyclerView.setOnFlingListener(null);
        startSnapHelper.attachToRecyclerView(duet_show_recyclerView);

        duet_close.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });

        readPost();
    }

    private void readPost(){
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("DuetPics").child(postid);
        reference.keepSynced(true);
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                postList.clear();
                for (DataSnapshot getsnapshot : dataSnapshot.getChildren()) {
                    for (DataSnapshot snapshot : getsnapshot.getChildren()) {
                        DisplayDuet displayDuet = snapshot.getValue(DisplayDuet.class);
                        postList.add(displayDuet);

                    }

                    Collections.reverse(postList);
                    postAdapter.notifyDataSetChanged();

                }

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }
}

Answer 1

我从你的问题中了解到，你想将点击位置从 DisplayDuetAdapter 传递到你的 DuetDisplayActivity。

如果是这种情况，那么您可以按意图通过它。

所以像这样在 DisplayDuetAdapter 中传递按下的项目位置：

  imageViewHolder.setiItemClickListener(new IItemClickListener() {
            @Override
            public void onItemClickListener(View view, int position) {
                Intent intent = new Intent(mContext, DuetDisplayActivity.class);
                //pass position like this
                intent.putExtra("position", i);
                intent.putExtra("postid", displayDuet.getPostid());
                intent.putExtra("publisherid", displayDuet.getPublisher());
                intent.putExtra("postduetid", displayDuet.getPostduetid());
                mContext.startActivity(intent);
            }
        });

并像这样获取 DuetDisplayActivity 中的位置：

private int position;

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

        Intent intent = getIntent();
        postid = intent.getStringExtra("postid");
        publisher = intent.getStringExtra("publisherid");
        postduetid = intent.getStringExtra("postduetid");
        //get the passed position
        position = intent.getIntExtra("position");

        ............
        ............

更新：

这样做：

        //get the passed position
         position = intent.getIntExtra("position",0);

从适配器中单击时，如何在 RecyclerView 中获取选定位置？

How do I get the selected position in a RecyclerView when clicked from from an adapter?

android

android-adapter

android-recyclerview