如何将 Firebase 中的图像检索到我的 android 应用程序中？

Question

i'm creaating an andoid app that fetches data from firebase and displays it. I successfully fetched text data from the firebase database but my images are not appearing. i strongly believe that the problem is with by adapter code below

package ke.co.catalystseller;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.squareup.picasso.Picasso;

import java.util.List;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ImageViewHolder> {
    private Context mContext;
    private List<Uploads> mUploads;

    public ImageAdapter(Context context, List<Uploads> uploads){
        mContext = context;
        mUploads = uploads;
    }

    public class ImageViewHolder extends RecyclerView.ViewHolder{
        public TextView textViewName;
        public ImageView imageView;
        public TextView vendor;
        public TextView vendorContact;

        public ImageViewHolder(@NonNull View itemView) {
            super(itemView);
            textViewName = itemView.findViewById(R.id.item_name);
            vendor = itemView.findViewById(R.id.seller_name);
            vendorContact = itemView.findViewById(R.id.ucontact);
            imageView = itemView.findViewById(R.id.m_image_view);
        }
    }

    @NonNull
    @Override
    public ImageViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(mContext).inflate(R.layout.image_item,parent,false);
        return new ImageViewHolder(v);
    }

    @Override
    public void onBindViewHolder(@NonNull ImageViewHolder holder, int position) {
        Uploads uploadCurrent = mUploads.get(position);
        holder.textViewName.setText(uploadCurrent.getName());
        holder.vendor.setText(uploadCurrent.getUser());
        holder.vendorContact.setText(uploadCurrent.getContact());
        Picasso.with(mContext)
                .load(uploadCurrent.getImageUrl())
                .placeholder(R.mipmap.ic_launcher)
                .fit()
                .centerCrop()
                .into(holder.imageView);

    }

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

any assistance will be highly appreciated

Answer 1

Try this

Put this method inside your view holder

 public void setImage(final Context c , final String imageUrl){

        final ImageView imageView = (ImageView)mView.findViewById(R.id.m_image_view);

        // This will save the image offline after downloading it once

        Picasso.with(c)
                .load(imageUrl)
                .networkPolicy(NetworkPolicy.OFFLINE)
                .resize(400, 300)
                .error(R.drawable.ic_error_black_24dp)
                .centerCrop()
                .into(imageView, new Callback() {
                    @Override
                    public void onSuccess() {
                    }

                    @Override
                    public void onError() {
                        // Try again if cache failed
                        Picasso.with(c)
                                .load(imageUrl)
                                .error(R.drawable.ic_error_black_24dp)
                                .into(imageView);
                    }
                });

    }

In the bind try this

  protected void onBindViewHolder(@NonNull MyViewHolder holder, int position) {


                    Uploads uploadCurrent = mUploads.get(position);
                    holder.textViewName.setText(uploadCurrent.getName());
                    holder.vendor.setText(uploadCurrent.getUser());
                    holder.vendorContact.setText(uploadCurrent.getContact());

                holder.setImage(getApplicationContext(),uploadCurrent.getImageUrl());




            }

Full code

package ke.co.catalystseller;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.squareup.picasso.Picasso;

import java.util.List;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ImageViewHolder> {
    private Context mContext;
    private List<Uploads> mUploads;

    public ImageAdapter(Context context, List<Uploads> uploads){
        mContext = context;
        mUploads = uploads;
    }

    public class ImageViewHolder extends RecyclerView.ViewHolder{
        public TextView textViewName;
        public ImageView imageView;
        public TextView vendor;
        public TextView vendorContact;

        public ImageViewHolder(@NonNull View itemView) {
            super(itemView);
            textViewName = itemView.findViewById(R.id.item_name);
            vendor = itemView.findViewById(R.id.seller_name);
            vendorContact = itemView.findViewById(R.id.ucontact);
            imageView = itemView.findViewById(R.id.m_image_view);
        }


 public void setImage(final Context c , final String imageUrl){

        final ImageView imageView = (ImageView)mView.findViewById(R.id.m_image_view);

        // This will save the image offline after downloading it once

        Picasso.with(c)
                .load(imageUrl)
                .networkPolicy(NetworkPolicy.OFFLINE)
                .resize(400, 300)
                .error(R.drawable.ic_error_black_24dp)
                .centerCrop()
                .into(imageView, new Callback() {
                    @Override
                    public void onSuccess() {
                    }

                    @Override
                    public void onError() {
                        // Try again if cache failed
                        Picasso.with(c)
                                .load(imageUrl)
                                .error(R.drawable.ic_error_black_24dp)
                                .into(imageView);
                    }
                });

    }


    }

    @NonNull
    @Override
    public ImageViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(mContext).inflate(R.layout.image_item,parent,false);
        return new ImageViewHolder(v);
    }

    @Override
    public void onBindViewHolder(@NonNull ImageViewHolder holder, int position) {

          Uploads uploadCurrent = mUploads.get(position);
                    holder.textViewName.setText(uploadCurrent.getName());
                    holder.vendor.setText(uploadCurrent.getUser());
                    holder.vendorContact.setText(uploadCurrent.getContact());

                holder.setImage(getApplicationContext(),uploadCurrent.getImageUrl());
    }

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

Answer 2

the problem i found actuallywas that i was uploading my images with the wrong url. this made it difficult to access them since the address url i was using to fetch them was different from the uploaded one. thanks