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Вячеслав
Asked:2020-11-07 02:15:36 +0000 UTC2020-11-07 02:15:36 +0000 UTC

如何在 RecyclerView 中从内存中加载图像？

  • 772

我尝试使用 Picasso 通过 uri 从内部存储器加载文件 它总是崩溃，给出错误 java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.ImageView Error on the line .load(uri ) 这是我的代码，请帮忙找出错误

import android.net.Uri;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import java.util.List;

import it.sephiroth.android.library.picasso.Picasso;

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

    private static final String LOG_TAG = "my_log";

    List<Cover> covers;

    RecyclerAdapter(List<Cover> covers) {
        this.covers = covers;
    }
    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView){
        super.onAttachedToRecyclerView(recyclerView);
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.card, parent, false);
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        Cover cover = covers.get(position);
        String filePath = String.valueOf(cover.getFileBookCover());
        Log.d(LOG_TAG, "Cover URI URI: " + filePath);
        Uri uri = cover.getFileBookCover();

        Picasso
                .with(holder.itemView.getContext())
                .load(uri)
                .into((ImageView) holder.itemView);

    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {

        CardView cardView;
        ImageView imgObl;

        ViewHolder (View itemView) {
            super(itemView);
            cardView = itemView.findViewById(R.id.card_view);
            imgObl = itemView.findViewById(R.id.iv_recycler_item);
        }
    }


}
android

1 个回答

  1. Best Answer

    .into((ImageView) holder.itemView);- 这里有错误。你必须写.into(holder.imgObl)

    你把毕加索扔到支架的根上，他不是ImageView

    并且最好在 holder 中创建一个公共方法，并在该方法中将调用bind()传递uri给 Picasso。对于 onBindViewHolder 方法中的适配器，调用holder.bind(uri)

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

private static final String LOG_TAG = "my_log";

List<Cover> covers;

RecyclerAdapter(List<Cover> covers) {
    this.covers = covers;
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView){
    super.onAttachedToRecyclerView(recyclerView);
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.card, parent, false);
    ViewHolder vh = new ViewHolder(v);
    return vh;
}

@Override
public void onBindViewHolder(ImageViewHolder holder, int position) {
    Cover cover = covers.get(position);
    String filePath = String.valueOf(cover.getFileBookCover());
    Log.d(LOG_TAG, "Cover URI URI: " + filePath);
    Uri uri = cover.getFileBookCover();
    holder.bind(uri);


}

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

public static class ImageViewHolder extends RecyclerView.ViewHolder {

    private CardView cardView;
    private ImageView imgObl;

    ViewHolder (View itemView) {
        super(itemView);
        cardView = itemView.findViewById(R.id.card_view);
        imgObl = itemView.findViewById(R.id.iv_recycler_item);
    }

    public void bind(Uri uri) {
        Picasso
                .with(itemView.getContext())
                .load(uri)
                .into(imgObl);   
    }
}

    }

    • 4

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