我有一个与 aRecyclerView和 an的活动ImageView。我正在使用RecyclerView水平显示图像列表。当我单击活动中的图像时,RecyclerView应该ImageView显示图像的更大图片。到目前为止一切正常。
RecyclerView
ImageView
现在活动中还有两个ImageButtons:imageButton_left和imageButton_right。当我单击 时imageButton_left,图像ImageView应向左转,并且缩略图RecyclerView应反映此更改。情况类似imageButton_right。
ImageButtons
imageButton_left
imageButton_right
我能够旋转ImageView. 但是,我怎样才能旋转缩略图RecyclerView?我怎样才能得到ViewHolder‘s ImageView?
ViewHolder
代码:
Activity 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()); } } }
我想您正在使用 aLinearLayoutManager来显示列表。它有一个很好的方法findViewByPosition叫做
LinearLayoutManager
findViewByPosition
查找表示给定适配器位置的视图。
您所需要的只是您感兴趣的项目的适配器位置。
编辑 :正如 Paul Woitaschek 在评论中指出的那样,它findViewByPosition是一种方法,LayoutManager因此它适用于所有 LayoutManagers(即StaggeredGridLayoutManager等)
LayoutManager
StaggeredGridLayoutManager