我试图在回收者视图中添加带有标题的flickr图像,遇到的问题是我想在循环中将图像及其标题传递给FlickrPhoto类(请看一下上面的内容,以了解我的意思),如果您会注意到这一行photos.add(new FlickrPhoto(title,uri));您会看到它在enqueue函数的循环内部运行,这是后台任务,所以我认识到该行未执行..但是当我尝试了enqueue函数后,它对我有用,但是当然只对一张图像起作用,因为,在循环之外。我尝试了很多解决方案,但都失败了

这是我的PhotoListActivity

package com.example.karim.bluecrunch;

/**
 * Created by karim on 8/26/16.
 */
public class FlickrPhoto {
    String title , image ;
    public  FlickrPhoto(String title , String image )
    {
        this.image = image;
        this.title = title;
    }
}


这是我的PhotosRecyclerViewAdapter

package com.example.karim.bluecrunch;
public class PhotosRecyclerViewAdapter extends RecyclerView.Adapter<PhotosRecyclerViewAdapter.PhotoViewHolder> {

    List<FlickrPhoto> photos = Collections.emptyList();
    Context context;
    LayoutInflater inflater;

    public PhotosRecyclerViewAdapter(Context context , List<FlickrPhoto> photos)
    {
        this.context = context;
        this.photos = photos;
        inflater = LayoutInflater.from(context);
    }

    @Override
    public PhotoViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View row = inflater.inflate(R.layout.single_row,parent,false);
        return new PhotoViewHolder(row);
    }

    @Override
    public void onBindViewHolder(PhotoViewHolder holder, int position) {
        FlickrPhoto photo = photos.get(position);
        holder.textView.setText(photo.title);
        Uri uri = Uri.parse(photo.image);
        Glide.with(context).load(uri).placeholder(R.drawable.image_placeholder).crossFade().into(holder.imageView);

    }

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

    public class PhotoViewHolder extends RecyclerView.ViewHolder {
        private TextView textView;
        private ImageView imageView;

        public PhotoViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.photoTitle);
            imageView = (ImageView) itemView.findViewById(R.id.flickrPhoto);
        }



    }
}


这是我的PhotosListActivity

package com.example.karim.bluecrunch;

public class PhotosListActivity extends AppCompatActivity {
    List<FlickrPhoto> photos ;
    ArrayList<String> photosTitles;
    ArrayList<String> photoURLS;
    String title;
    String uri;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_photos_list);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.photo_recycler_view);
        recyclerView.setLayoutManager(new GridLayoutManager(getApplicationContext(),2));
        PhotosRecyclerViewAdapter adapter = new PhotosRecyclerViewAdapter(this,getPhotos());
        recyclerView.setAdapter(adapter);
    }

    public List<FlickrPhoto> getPhotos()
    {

        photos = new ArrayList<>();

        final String API_KEY = "fdac2e9676991ac53b34651adab52518";
        final String METHOD = "flickr.photos.search";
        final String AUTH_TOKEN = "72157671978046542-6e266595ffed01f8";
        final String API_SIG = "58e08d365779a8f2e946a2b5320199e2";
        final String FORMAT = "json";
        final int CALL_BACK = 1;

        HandleRetrofit handleRetrofit = HandleRetrofit.retrofit.create(HandleRetrofit.class);
        Call<Photos> call = handleRetrofit.Photos(METHOD,API_KEY,FORMAT,CALL_BACK,AUTH_TOKEN,API_SIG);
        call.enqueue(new Callback<Photos>() {
            @Override
            public void onResponse(Call<Photos> call, Response<Photos> response) {
                Log.d("MainActivity", "Status Code = " + response.code());
                PhotosRetrofit photosRetrofit = response.body().photos;
                for (int i = 0; i < photosRetrofit.getPhoto().size(); i++) {
                    uri="https://farm"+photosRetrofit.getPhoto().get(i).getFarm()+".staticflickr.com/"+
                            photosRetrofit.getPhoto().get(i).getServer()+"/"+
                            photosRetrofit.getPhoto().get(i).getId()+"_" +
                            photosRetrofit.getPhoto().get(i).getSecret()+".jpg";

                    title= photosRetrofit.getPhoto().get(i).getTitle();

                    photos.add(new FlickrPhoto(title,uri));


                    Log.w(">>>>>>>>>>>","https://farm"+photosRetrofit.getPhoto().get(i).getFarm()+".staticflickr.com/"+
                            photosRetrofit.getPhoto().get(i).getServer()+"/"+
                            photosRetrofit.getPhoto().get(i).getId()+"_" +
                            photosRetrofit.getPhoto().get(i).getSecret()+".jpg");
                }

            }

            @Override
            public void onFailure(Call<Photos> call, Throwable t) {
                Toast.makeText(PhotosListActivity.this,"Error :"+t.getMessage(),Toast.LENGTH_LONG).show();
                Log.w("---___--- Error ",t.getMessage());
            }
        });
    /*    Log.w("Hello",uri.toString());
        Log.w("Hello",title.toString());*/
        photos.add(new FlickrPhoto("karim","https://farm9.staticflickr.com/8450/29141814932_a62977990d.jpg"));
        return photos;
    }
}


一切正常,但我的活动中此行的主要问题

photos.add(new FlickrPhoto(title,uri));


我认为这不能在后台任务中完成,因为这一行

photos.add(new FlickrPhoto("karim","https://farm9.staticflickr.com/8450/29141814932_a62977990d.jpg"));


在入队功能之后可以很好地工作,但是我不知道如何解决这样的问题。

编辑

请注意,循环

for (int i = 0; i < photosRetrofit.getPhoto().size(); i++)
{
uri="https://farm"... ;
title= ..;
 **photos.add(new FlickrPhoto(title,uri));**
 Log.w(">>>>>>>>>>>","https://farm"+photosRetrofit.getPhoto()‌​.get(i).getFarm()+".‌​staticflickr.com/"+p‌​hotosRetrofit.getPho‌​to().get(i).getServe‌​r()+"/"+photosRetrof‌​it.getPhoto().get(i)‌​.getId()+"_" +photosRetrofit.getPhoto().get(i).getSecret()+".jpg");
 }


不会跳过是因为,如果您尝试在循环中记录标题或uri,它将成功在Logcat中显示。主要问题是这行代码photos.add(new FlickrPhoto(title,uri));将数据“ title和uri”传递给FlickrPhoto类的构造函数,并且此操作在队列中-> onResponse(背景任务),我不知道为什么它不起作用

将数据(图像和标题)加载到回收器视图中是例外,但是实际上什么也没有发生,并且

我尝试了几件事

首先,在PhotosListActivity类返回photos()arrayList之前,我尝试将固定数据传递给FlickrPhoto类的Constructor,并且它可以正常工作并将图像显示在回收视图中

其次,我尝试向FlickrPhoto类添加默认的构造函数和setter,用于标题和图像的getter,并在PhotosListActivity类的OnCreate函数上对其进行初始化,然后在入队时使用我的setter和getter,它可以工作并成功加载所有数据,但是当我再次尝试运行时,一切都消失了! :(,我不知道为什么

做二传手和吸气剂是这样的
FlickrPhoto.java类

package com.example.karim.bluecrunch;

/**
 * Created by karim on 8/26/16.
 */
public class FlickrPhoto {
    String title , image ;
    public FlickrPhoto(){}
    public  FlickrPhoto(String title , String image )
    {
        this.image = image;
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

}


和PostListActivity类

package com.example.karim.bluecrunch;

import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;

import java.net.URI;
import java.util.ArrayList;
import java.util.List;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.http.Url;

public class PhotosListActivity extends AppCompatActivity {
    List<FlickrPhoto> photos ;
    ArrayList<String> photosTitles;
    ArrayList<String> photoURLS;
    FlickrPhoto flickrPhoto ;
    String title;
    String uri;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_photos_list);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.photo_recycler_view);
        recyclerView.setLayoutManager(new GridLayoutManager(this,2));
        PhotosRecyclerViewAdapter adapter = new PhotosRecyclerViewAdapter(this,getPhotos());
        recyclerView.setAdapter(adapter);

        flickrPhoto = new FlickrPhoto();



    }

    public List<FlickrPhoto> getPhotos()
    {

        photos = new ArrayList<>();

        final String API_KEY = "fdac2e9676991ac53b34651adab52518";
        final String METHOD = "flickr.photos.search";
        final String AUTH_TOKEN = "72157671978046542-6e266595ffed01f8";
        final String API_SIG = "58e08d365779a8f2e946a2b5320199e2";
        final String FORMAT = "json";
        final int CALL_BACK = 1;

        HandleRetrofit handleRetrofit = HandleRetrofit.retrofit.create(HandleRetrofit.class);
        Call<Photos> call = handleRetrofit.Photos(METHOD,API_KEY,FORMAT,CALL_BACK,AUTH_TOKEN,API_SIG);
        call.enqueue(new Callback<Photos>() {
            @Override
            public void onResponse(Call<Photos> call, Response<Photos> response) {
                Log.d("MainActivity", "Status Code = " + response.code());
                PhotosRetrofit photosRetrofit = response.body().photos;
                //photosRetrofit.getPhoto().size()
                for (int i = 0; i < photosRetrofit.getPhoto().size(); i++) {
                    uri="https://farm"+photosRetrofit.getPhoto().get(i).getFarm()+".staticflickr.com/"+
                            photosRetrofit.getPhoto().get(i).getServer()+"/"+
                            photosRetrofit.getPhoto().get(i).getId()+"_" +
                            photosRetrofit.getPhoto().get(i).getSecret()+".jpg";

                    title= photosRetrofit.getPhoto().get(i).getTitle();

                    flickrPhoto.setImage(uri);
                    flickrPhoto.setTitle(title);

                    photos.add(new FlickrPhoto(flickrPhoto.getTitle(),flickrPhoto.getImage()));


                    Log.w("++++++++++++",photosRetrofit.getPhoto().get(i).getTitle());

                    Log.w(">>>>>>>>>>>","https://farm"+photosRetrofit.getPhoto().get(i).getFarm()+".staticflickr.com/"+
                            photosRetrofit.getPhoto().get(i).getServer()+"/"+
                            photosRetrofit.getPhoto().get(i).getId()+"_" +
                            photosRetrofit.getPhoto().get(i).getSecret()+".jpg");



                }

            }

            @Override
            public void onFailure(Call<Photos> call, Throwable t) {
                Toast.makeText(PhotosListActivity.this,"Error :"+t.getMessage(),Toast.LENGTH_LONG).show();
                Log.w("---___--- Error ",t.getMessage());
            }
        });
    /*    Log.w("Hello",uri.toString());
        Log.w("Hello",title.toString());*/
        photos.add(new FlickrPhoto("karim","https://farm9.staticflickr.com/8450/29141814932_a62977990d.jpg"));
        return photos;
    }
}

最佳答案

问题在于RecyclerView在将元素及其数据添加到数组列表后不会自动更新。您需要在适配器上调用notifyDataSetChanged()以强制执行此更新。

07-27 20:11