Question

我正在使用Recyclerview，我想将图像设置为Recyclerview所选项目的中心imageview

错误：您必须传入非空视图

此处我尝试将图片设置为位于activity_set_back.xml的{{1}}的图像视图，来自Recyclerview的Onclick方法

我有：moviesList(ArrayList)包含所有网址而且我在点击时获得了位置我唯一需要做的就是将该图像设置为img_back（Imageview）此代码中显示

MoviesAdapter.class

这是我的适配器

    public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {

    String string_url;
    String clicked_url;
    private ArrayList<Image> moviesList;

    public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        public ImageView img_backimage;
        public ImageView img_back;

        public MyViewHolder(View itemView) {
            super(itemView);
            img_backimage = (ImageView) itemView.findViewById(R.id.img_backimage);
            img_back =(ImageView) itemView.findViewById(R.id.img_edit_this);
            itemView.setOnClickListener(this);


        }

        @Override
        public void onClick(View view) {
            int position = getLayoutPosition(); // gets item position
            clicked_url= moviesList.get(position).getPath();
            Toast.makeText(view.getContext(),position+"",Toast.LENGTH_LONG).show();
            Glide.with(view.getContext()).load(clicked_url)
                    .diskCacheStrategy(DiskCacheStrategy.ALL)
                    .fitCenter()
                    .crossFade()
                    .into(img_back);
        }

    }

    public MoviesAdapter(ArrayList<Image> moviesList) {
        this.moviesList = moviesList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View rootView = inflater.inflate(R.layout.image_list_row, parent, false);
        return new MyViewHolder(rootView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        string_url= moviesList.get(position).getPath();
        Glide.with(holder.img_backimage.getContext()).load(string_url)
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .fitCenter()
                .crossFade()
                .into(holder.img_backimage);
    }
    @Override
    public int getItemCount() {
        return moviesList.size();
    }
}

image_list_row.xml

<?xml version="1.0" encoding="utf-8"?>


 <RelativeLayout
        android:id="@+id/rl_single_item"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="?android:attr/selectableItemBackground"
        android:clickable="true"
        android:focusable="true"
        android:orientation="horizontal"
        android:paddingBottom="8dp"
        android:paddingLeft="4dp"
        android:paddingRight="4dp"
        android:paddingTop="6dp">


        <ImageView
            android:id="@+id/img_backimage"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_centerInParent="true"
            android:scaleType="fitCenter"
            android:src="@drawable/background"/>

    </RelativeLayout>

activity_set_back.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.weblogicindia.paint.SetBackActivity">

    <RelativeLayout
        android:id="@+id/rl_Paint_Area_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/grid_view_container">

        <RelativeLayout
            android:id="@+id/rl_Paint_Area2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:gravity="center"
            >

            <ImageView
                android:id="@+id/img_edit_this"
                android:layout_centerInParent="true"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:adjustViewBounds="true"
                android:scaleType="fitCenter"
                android:src="@drawable/background"/>


        </RelativeLayout>

    </RelativeLayout>

    <RelativeLayout
        android:id="@+id/grid_view_container"
        android:layout_width="match_parent"
        android:layout_alignParentBottom="true"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

    </RelativeLayout>
</RelativeLayout>

Answer 1

此处imageview - img_edit_this位于您的活动中，而不在项目视图中。为了从适配器访问活动中的imageview，首先需要在适配器初始化期间将活动的列表器传递给适配器。然后在适配器中使用此侦听器来更改活动中的imageview。

首先创建一个这样的界面

public interface RecyclerImageClick {
void onCenterImageChange(String imagePath);
}

让你的活动实现这一点，对于egs

public class MembersList extends AppCompatActivity implements RecyclerImageClick

现在在活动

中实施方法onCenterImageChange(String imagePath)

现在初始化适配器时，将此列表器与arraylist一起传递给它

data= new MoviesAdapter(ArrayList<Image> moviesList,this);

现在更改你的适配器构造函数

private RecyclerImageClick listener;
public MoviesAdapter(ArrayList<Image> moviesList,RecyclerImageClick listener) {
        this.moviesList = moviesList;
        this.listener=listener;
    }

现在在适配器的imageview内点击监听器调用listener.onCenterImageChange(imagePath)

现在，在您的活动中，声明您的imageview并将其设置为从adapter传递的图像路径

Answer 2

不要使用onclick RecyclerView方法来检测子点击，而是使用ClickListener方法在bind方法中使用@Override public void onBindViewHolder(final MyViewHolder holder, int position) { string_url= moviesList.get(position).getPath(); Glide.with(holder.img_backimage.getContext()).load(string_url) .diskCacheStrategy(DiskCacheStrategy.ALL) .fitCenter() .crossFade() .into(holder.img_backimage); holder.itemView.setonClickListener(new View.OnClickListener(){ Glide.with(view.getContext()).load(string_url) .diskCacheStrategy(DiskCacheStrategy.ALL) .fitCenter() .crossFade() .into(img_back); }); }，如

zoomLevel

对项目的Recyclerview单击将图像设置为活动中的另一个imageview

2 个答案: