android - 使用两个应用程序从firebase中检索图像

Question

我是应用开发的新手。我在firebase中链接了两个应用程序，一个用于将图像发送到Firebase存储，图像URL用于Firebase实时数据库，另一个用于使用RecyclerView检索所有图像。第一个应用程序正常运行。但第二个没有做任何事情。它仅显示布局到达。

arrivals.xml代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context="gr.packagename.name.MainActivity"
     android:background="@drawable/background">

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="100dp"
    android:src="@drawable/logo"/>

<android.support.v7.widget.RecyclerView
    android:id="@+id/arrivals_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="16dp"
    android:layout_marginRight="16dp"
    android:layout_marginTop="144dp" />

</RelativeLayout>

model.xml代码

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView    xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="1">

    <ImageView
        android:layout_width="100dp"
        android:layout_height="200dp"
        android:id="@+id/clothesimage"
        android:src="@drawable/men"/>

    <TextView
        android:layout_width="74dp"
        android:layout_height="wrap_content"
        android:id="@+id/categoryimage"
        android:text="category"
        android:layout_alignBottom="@+id/clothesimage"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:textSize="18sp" />

</LinearLayout>
</android.support.v7.widget.CardView>

到达代码.java

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.squareup.picasso.Picasso;

public class arrivals extends AppCompatActivity {

DatabaseReference mdatabase;
RecyclerView rv;

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

    mdatabase = FirebaseDatabase.getInstance().getReference().child("Images");

    rv = (RecyclerView) findViewById(R.id.arrivals_list);
    rv.setHasFixedSize(true);
    rv.setLayoutManager(new LinearLayoutManager(this));

}

@Override
protected void onStart(){
    super.onStart();

    FirebaseRecyclerAdapter<Images, ImageViewHolder> firebaseadapter = new FirebaseRecyclerAdapter<Images, ImageViewHolder>(
            Images.class,
            R.layout.list_content,
            ImageViewHolder.class,
            mdatabase
    ) {
        @Override
        protected void populateViewHolder(ImageViewHolder viewHolder, Images model, int position) {
            viewHolder.setCategory(model.getCategory());
            viewHolder.setImageurl(getApplicationContext(), model.getImageurl());

        }
    };

    rv.setAdapter(firebaseadapter);
}

public static class ImageViewHolder extends RecyclerView.ViewHolder{

    View mView;

    public ImageViewHolder(View itemView){
        super(itemView);

        mView = itemView;

    }

    public void setCategory(String category){

        TextView categoryimg = (TextView) mView.findViewById(R.id.categoryimage);
        categoryimg.setText(category);

    }

    public void setImageurl(Context ctx, String imageurl){

        ImageView img = (ImageView) mView.findViewById(R.id.clothesimage);
        Picasso.with(ctx).load(imageurl).into(img);
    }
}
}

Images.java代码

public class Images {

private String imageurl;
private String category;

public Images() {
}


public String getImageurl() {
    return imageurl;
}

public void setImageurl(String imageurl) {
    this.imageurl = imageurl;
}

public String getCategory() {
    return category;
}

public void setCategory(String category) {
    this.category = category;
}
}