RecyclerView-在特定位置获取视图

Question

我有一个与RecyclerView和一起进行的活动ImageView。我正在使用RecyclerView来水平显示图像列表。当我点击在图像上RecyclerView的ImageView在活动中应显示图像的大局观。到目前为止，一切正常。

现在ImageButtons，活动中还有两个：imageButton_left和imageButton_right。当我单击时imageButton_left，中的图像ImageView应左移，并且中的缩略图也RecyclerView应反映此更改。与的情况类似imageButton_right。

我能够旋转ImageView。但是，如何旋转缩略图RecyclerView？我如何获得ViewHolder的ImageView？

码：

活动XML：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp" />


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/original_image"
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:scaleType="fitXY"
            android:src="@drawable/image_not_available_2" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:gravity="center_horizontal"
            android:orientation="horizontal">


            <ImageButton
                android:id="@+id/imageButton_left"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginRight="20dp"
                android:background="@drawable/rotate_left_icon" />

            <ImageButton
                android:id="@+id/imageButton_right"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="@drawable/rotate_right_icon" />

        </LinearLayout>
    </LinearLayout>
</LinearLayout>

我的活动代码：

public class SecondActivity extends AppCompatActivity implements IRecyclerViewClickListener {


    RecyclerView mRecyclerView;
    LinearLayoutManager mLayoutManager;
    RecyclerViewAdapter mRecyclerViewAdapter;
    List<String> urls = new ArrayList<String>();
    ImageView mOriginalImageView;
    ImageButton mLeftRotate, mRightRotate;

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

        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        mLayoutManager = new LinearLayoutManager(this, android.support.v7.widget.LinearLayoutManager.HORIZONTAL, false);
        mLayoutManager.setOrientation(android.support.v7.widget.LinearLayoutManager.HORIZONTAL);
        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerViewAdapter = new RecyclerViewAdapter(this, urls);
        mRecyclerView.setAdapter(mRecyclerViewAdapter);

        mOriginalImageView = (ImageView) findViewById(R.id.original_image);
        mLeftRotate = (ImageButton) findViewById(R.id.imageButton_left);
        mLeftRotate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mOriginalImageView.setRotation(mOriginalImageView.getRotation() - 90);
            }
        });


        mRightRotate = (ImageButton) findViewById(R.id.imageButton_right);
        mRightRotate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mOriginalImageView.setRotation(mOriginalImageView.getRotation() + 90);
            }
        });

        Intent intent = getIntent();
        if (intent != null) {

            String portfolio = intent.getStringExtra("portfolio");

            try {

                JSONArray jsonArray = new JSONArray(portfolio);

                for (int i = 0; i < jsonArray.length(); i++) {

                    JSONObject jsonObject = jsonArray.getJSONObject(i);

                    String url = jsonObject.getString("url");
                    urls.add(url);
                }

                Log.d(Const.DEBUG, "URLs: " + urls.toString());

                mRecyclerViewAdapter.notifyDataSetChanged();

            } catch (Exception e) {
                e.printStackTrace();
            }

        }

    }


    @Override
    public void onItemClick(int position) {
        Picasso.with(this).load(urls.get(position)).into(mOriginalImageView);
    }
}

我的RecyclerView自定义适配器：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {

    Context context;
    List<String> mUrls = new ArrayList<String>();

    IRecyclerViewClickListener mIRecyclerViewClickListener;

    public int position;

    public int getPosition() {
        return position;
    }

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



    public RecyclerViewAdapter(Context context, List<String> urls) {
        this.context = context;
        this.mUrls.clear();
        this.mUrls = urls;

        Log.d(Const.DEBUG, "Urls Size: " + urls.size());
        Log.d(Const.DEBUG, urls.toString());

        if (context instanceof IRecyclerViewClickListener)
            mIRecyclerViewClickListener = (IRecyclerViewClickListener) context;
        else
            Log.d(Const.DEBUG, "Implement IRecyclerViewClickListener in Activity");
    }

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

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        Picasso.with(context).load(mUrls.get(position)).into(holder.mImageView);
    }

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


    public void rotateThumbnail() {


    }

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

        public ImageView mImageView;
        public View v;

        public ViewHolder(View v) {
            super(v);
            v.setTag(getAdapterPosition());
            v.setOnClickListener(this);
            this.mImageView = (ImageView) v.findViewById(R.id.image);
        }

        @Override
        public void onClick(View v) {
            this.v = v;
            mIRecyclerViewClickListener.onItemClick(getAdapterPosition());
        }
    }


}

Answer 1

我想您正在使用a
LinearLayoutManager来显示列表。它有所谓的一个很好的方法findViewByPosition是

查找代表给定适配器位置的视图。

您所需要的只是您感兴趣的商品的适配器位置。

编辑 ：正如 Paul Woitaschek
在评论中所指出的，findViewByPosition是一种方法，LayoutManager因此它可以与所有LayoutManagers一起使用（例如StaggeredGridLayoutManager，等等）。