java - 如何在 Android Studio 的 Recyclerview 中显示从 API 获取的 JPG 图像？

Question

图像正在 RecipeApiActivity 中下载 - 我可以在名为“imigiview”的测试 ImageView 中看到它们，因此 API 请求有效!但我希望它们在回收器 View 中正确显示 - 现在它什么也不显示。
为此，我创建了一个位图列表，其中放置了所有下载的位图，该列表被提供给应该将它们放置在 RecyclerView 中的 RecipeAPIAdapter。
你能帮我找出为什么图像不显示吗？ ( Logcat 没有给我任何类型的错误)

package byDragosT.myapplication;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;
import android.widget.TextView;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Map;
// Aceasta activitate detine o lista de retete gasita pe spoontacular bagata in recyclerview//
// Va lua un RecipeItem si il va baga in RecipeApiAdapter si apoi il conecteaza la recyclerview

public class RecipeAPIActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;
    private RecipeApiAdapter adapter;
    // private TextView jsonUnparsedResult;
    private ImageView imigiView;
    private ArrayList<Bitmap> images = new ArrayList<>(8);
    private Context context;

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

        String url1 = "flour";   // just for simplifying the stackOverflow question I put this value here
        String url2 = "egg";     // just for simplifying the stackOverflow question I put this value here
        String url3 = "salt";    // just for simplifying the stackOverflow question I put this value here

        String urlfinal = "https://spoonacular-recipe-food-nutrition-v1.p.rapidapi.com/recipes/findByIngredients?number=5&ranking=1&ignorePantry=false&ingredients=" + url1 + url2 + url3;
        System.out.println(urlfinal);

        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(urlfinal)
                .get()
                .addHeader("x-rapidapi-host", "spoonacular-recipe-food-nutrition-v1.p.rapidapi.com")
                .addHeader("x-rapidapi-key", "key hidden") 
                .build();
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
                e.printStackTrace();
            }

            @Override
            public void onResponse(final Response response) throws IOException {
                if (response.isSuccessful()){
                    //Aici inca suntem pe background thread - metoda enqueue -- //
                    final String myResponse;
                    myResponse = response.body().string();
                    // Aici trecem pe threadul principal din nou //
                    RecipeAPIActivity.this.runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            // jsonUnparsedResult.setText(myResponse);
                            System.out.println(myResponse);
                            try {
                                JSONArray results = new JSONArray(myResponse);
                                if(results.length() > 0){
                                    for (int i = 0; i < results.length(); i++){
                                        JSONObject object = results.getJSONObject(i);
                                        // jsonUnparsedResult.setText(object.getString("title"));
                                        System.out.println(object.getString("image"));
                                        // SPRITES
                                        String imgUrl = object.getString("image");    //  aici sprites e Obiect cu 8 perechi key-values
                                        new DownloadSpriteTask().execute(imgUrl);
                                    }
                                }
                            } catch (JSONException e) { e.printStackTrace(); }
                        }
                    });
                }
            }
        });

        imigiView = findViewById(R.id.imaginedetest); // on post execute at Asynktask
        recyclerView = findViewById(R.id.recyclerView);
        layoutManager = new LinearLayoutManager(context);
        recyclerView.setLayoutManager(layoutManager);
        // System.out.println("ce se intampla" + images);
        adapter = new RecipeApiAdapter(images);
        recyclerView.setAdapter(adapter);
        // jsonUnparsedResult = findViewById(R.id.JsonExample);
    }

    private class DownloadSpriteTask extends AsyncTask<String, Void, Bitmap> {
        @Override
        protected Bitmap doInBackground(String... strings) {
            try {
                URL url = new URL(strings[0]);
                return BitmapFactory.decodeStream(url.openStream());
            } catch (IOException e) {
                Log.e("cs50", "Download sprite error", e);
                return null;
            }
        }
        @Override
        protected void onPostExecute(Bitmap bitmap) {
            imigiView.setImageBitmap(bitmap);
            images.add(bitmap);       /// images e facut sa ia int ca valoare nu Bitmap
            System.out.println("Another photo attached!");
        }
    }

    /// Ingredients should be comma separated ////   symbol for ',' is %252C
    //// symbol for space ' ' is %20   //
    public String urlify (String ingredient, String vitamina){
        String theUrl = "";
        if (ingredient.equals("Choose a " + vitamina + " ingredient")){
            System.out.println("VA RUGAM sa introduceti ceva ok !!!!!!!!!!");
            ingredient = "";
        }else{
            String[] splitResult = ingredient.split(" ",8);
            for (String word:splitResult){
                if (word.equals("-")){
                    theUrl = theUrl + "%252C";
                    break;
                }else theUrl = theUrl + word + "%20";
            }
        }
        return theUrl;
    }
}

食谱API适配器

package byDragosT.myapplication;

import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;

public class RecipeApiAdapter extends RecyclerView.Adapter<RecipeApiAdapter.RecipeViewHolder> {
    private ArrayList<Bitmap> images;

    public RecipeApiAdapter(ArrayList<Bitmap> images){
        this.images = images;
    }
    public static class RecipeViewHolder extends RecyclerView.ViewHolder {
        public ImageView pozaReteta;
        public TextView titlu;
        public TextView descriere;

        RecipeViewHolder(View view){
            super(view);
            pozaReteta = view.findViewById(R.id.poza);
            titlu = view.findViewById(R.id.recipe_name);
            descriere = view.findViewById(R.id.ingredients_list);
        }
    }
    @NonNull
    @Override    //// Mare grija ce layout pui aici - sfat pentru viitor - mi-a luat 4 ore sa gasesc eroarea
    public RecipeViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recipe_item_in_recyclerview_api, parent, false);
        RecipeViewHolder recipeViewHolder = new RecipeViewHolder(view);
        return recipeViewHolder;
    }
    @Override
    public void onBindViewHolder(@NonNull RecipeViewHolder holder, int position) {
        Bitmap image_id = images.get(position);
        holder.pozaReteta.setImageBitmap(image_id);
        holder.titlu.setText("Image: "+ position);
    }
    @Override
    public int getItemCount() {
        return images.size();
    }
}

activity_recipe_api.xml

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

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical" />

    <TextView
        android:id="@+id/JsonExample"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentEnd="true"
        android:layout_alignParentBottom="true"
        android:layout_marginEnd="150dp"
        android:layout_marginBottom="8dp"
        android:text="Testing testing 123"
        android:background="@color/colorPrimaryDark"
        android:textColor="@android:color/background_light"
        app:layout_constraintStart_toEndOf="@+id/recyclerView" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imaginedetest"
        android:contentDescription="@string/imagine_de_test" />

</RelativeLayout>

recipe_item_in_recyclerview_api.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="wrap_content"
    android:orientation="vertical"
    android:padding="10dp">

    <ImageView
        android:id="@+id/poza"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="2dp"
        android:paddingTop="10dp"
        app:layout_constraintEnd_toStartOf="@+id/ingredients_list"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:srcCompat="@android:drawable/sym_def_app_icon" />

    <TextView
        android:id="@+id/recipe_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="@string/mankarika_super"
        android:textAlignment="center"
        android:textSize="18sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.52"
        app:layout_constraintStart_toEndOf="@+id/poza"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/ingredients_list"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:paddingTop="5dp"
        android:text="Se face din: ceapa, apa, si multe multe multe multe multe multe multe multe multe multe multe multe chestii"
        android:textAlignment="gravity"
        android:textSize="12sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/poza"
        app:layout_constraintTop_toBottomOf="@+id/recipe_name" />

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

对于图像加载，迄今为止最简单的方法是使用 Picasso或Glide .

老实说，我不知道如何在不使用这些库的情况下做到这一点:)