Question

您好我通过链接循环视图和MYSQL PHP成功插入项目，但删除项目仍然失败。您可以在客户端删除它，但我一直在使用PHP和MYSQL失败。我可以获得有关此示例或代码的帮助吗？

这是recyclerview适配器代码

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

    //Imageloader to load image
    private ImageLoader imageLoader;
    private Context context;

    //List to store all superheroes
    List<recyclerview_list> recyclerview_lists;

    //Constructor of this class
    public CardAdapter(List<recyclerview_list> recyclerview_lists, recyclerview context) {
        super();
        //Getting all superheroes
        this.recyclerview_lists = recyclerview_lists;
        this.context = (Context) context;
    }

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

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

        //Getting the particular item from the list
        recyclerview_list recyclerview_List = recyclerview_lists.get(position);

        //Loading image from url
        imageLoader = CustomVolleyRequest.getInstance(context).getImageLoader();
        imageLoader.get(recyclerview_List.getImage_path(), ImageLoader.getImageListener(holder.imageView, R.drawable.ic_launcher_background, android.R.drawable.ic_dialog_alert));

        //Showing data on the views
        holder.imageView.setImageUrl(recyclerview_List.getImage_path(), imageLoader);
        holder.textViewName.setText(recyclerview_List.getImage_name());

    }

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

    class ViewHolder extends RecyclerView.ViewHolder {
        //Views
        public NetworkImageView imageView;
        public TextView textViewName;
        public Button deleteButton;

        //Initializing Views
        public ViewHolder(final View itemView) {
            super(itemView);
            imageView = (NetworkImageView) itemView.findViewById(R.id.imageViewHero);
            textViewName = (TextView) itemView.findViewById(R.id.textViewName);
            deleteButton = (Button) itemView.findViewById(R.id.buttonDelete);
            deleteButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Toast.makeText(context, "Delete", Toast.LENGTH_SHORT).show();
                    delete(getAdapterPosition());


                }
            });

        }

        public void delete(int position) {

            try {
                recyclerview_lists.remove(position);
                notifyItemRemoved(position);
            } catch (IndexOutOfBoundsException ex) {
                ex.printStackTrace();
            }
        }
    }
}

这是PHP代码

$con = mysqli_connect("", "", "", "");

$id = $_POST["id"];

$statement = mysqli_prepare($con, "DELETE FROM image WHERE id = ?");
mysqli_stmt_bind_param($statement, "s", $id);
mysqli_stmt_execute($statement);

$response = array();
$response["success"] = true;

echo json_encode($response);

Answer 1

在适配器调用中添加新方法

  public void deleteFromServer(int id)
        {
         url = "http://yoururl/delete_image.php";
            StringRequest postRequest = new StringRequest(Request.Method.POST, url, 
                new Response.Listener<String>() 
                {
                    @Override
                    public void onResponse(String response) {
                        // if success 
                        delete(id)
                        Log.d("Response", response);
                    }
                }, 
                new Response.ErrorListener() 
                {
                     @Override
                     public void onErrorResponse(VolleyError error) {
                         // error
                         Log.d("Error.Response", response);
                   }
                }
            ) {     
                @Override
                protected Map<String, String> getParams() 
                {  
                        Map<String, String>  params = new HashMap<String, String>();  
                        params.put("id", id);  

                        return params;  
                }
            };
            queue.add(postRequest);
        }

从适配器类

调用此方法

deleteButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Toast.makeText(context, "Delete", Toast.LENGTH_SHORT).show();
                    deleteFromServer(recyclerview_lists.get(getAdapterPosition()).id);


                }
            });

Answer 2

代码很好，但无法获取已识别的ID。我将分享我的全部工作。

Config.java

public static final String DATA_URL = "http:// /images/feed.php?page=";

/*Json으로 가져오는 이미지 테이블의 목록*/

// 이미지 주소
public static final String TAG_IMAGE_URL = "image_path";
// 이미지 이름
public static final String TAG_NAME = "image_name";

}

自定义排球Request.java

private static CustomVolleyRequest customVolleyRequest;
private static Context context;
private RequestQueue requestQueue;
private ImageLoader imageLoader;

private CustomVolleyRequest(Context context) {

    this.context = context;
    this.requestQueue = getRequestQueue();

    imageLoader = new ImageLoader(requestQueue,
            new ImageLoader.ImageCache() {
                private final LruCache<String, Bitmap>
                        cache = new LruCache<String, Bitmap>(20);

                @Override
                public Bitmap getBitmap(String url) {
                    return cache.get(url);
                }

                @Override
                public void putBitmap(String url, Bitmap bitmap) {
                    cache.put(url, bitmap);
                }
            });
}

public static synchronized CustomVolleyRequest getInstance(Context context) {
    if (customVolleyRequest == null) {
        customVolleyRequest = new CustomVolleyRequest(context);
    }
    return customVolleyRequest;
}

public RequestQueue getRequestQueue() {
    if (requestQueue == null) {
        Cache cache = new DiskBasedCache(context.getCacheDir(), 10 * 1024 * 1024);
        Network network = new BasicNetwork(new HurlStack());
        requestQueue = new RequestQueue(cache, network);
        requestQueue.start();
    }
    return requestQueue;
}

public ImageLoader getImageLoader() {
    return imageLoader;
}

}

recyclerview_list.java

private  String image_path;
private  String image_name;

public String getImage_path() {
    return image_path;
}

public void setImage_path(String image_path) {
    this.image_path = image_path;
}

public String getImage_name() {
    return image_name;
}

public void setImage_name(String image_name) {
    this.image_name = image_name;
}

recyclerview。的java

//创建超级英雄列表私人清单listSuperHeroes;

//Creating Views
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
private RecyclerView.Adapter adapter;


//Volley Request Queue
private RequestQueue requestQueue;

//The request counter to send ?page=1, ?page=2  requests
private int requestCount = 1;

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

    //Initializing Views
    recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
    recyclerView.setHasFixedSize(true);
    layoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(layoutManager);

    //Initializing our superheroes list
    listSuperHeroes = new ArrayList<>();
    requestQueue = Volley.newRequestQueue(this);

    //Calling method to get data to fetch data
    getData();

    //Adding an scroll change listener to recyclerview
    recyclerView.setOnScrollChangeListener(this);

    //initializing our adapter
    adapter = new CardAdapter(listSuperHeroes ,this);

    //Adding adapter to recyclerview
    recyclerView.setAdapter(adapter);
}

//Request to get json from server we are passing an integer here
//This integer will used to specify the page number for the request ?page = requestcount
//This method would return a JsonArrayRequest that will be added to the request queue
private JsonArrayRequest getDataFromServer(int requestCount) {
    //Initializing ProgressBar
    final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar1);

    //Displaying Progressbar
    progressBar.setVisibility(View.VISIBLE);
    setProgressBarIndeterminateVisibility(true);

    //JsonArrayRequest of volley
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Config.DATA_URL + String.valueOf(requestCount),
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    //Calling method parseData to parse the json response
                    parseData(response);
                    //Hiding the progressbar
                    progressBar.setVisibility(View.GONE);
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    progressBar.setVisibility(View.GONE);
                    //If an error occurs that means end of the list has reached
                    Toast.makeText(recyclerview.this, "No More Items Available", Toast.LENGTH_SHORT).show();
                }
            });

    //Returning the request
    return jsonArrayRequest;
}

//This method will get data from the web api
private void getData() {
    //Adding the method to the queue by calling the method getDataFromServer
    requestQueue.add(getDataFromServer(requestCount));
    //Incrementing the request counter
    requestCount++;
}

//This method will parse json data
private void parseData(JSONArray array) {
    for (int i = 0; i < array.length(); i++) {
        //Creating the superhero object
        recyclerview_list recyclerviewList = new recyclerview_list();
        JSONObject json = null;
        try {
            //Getting json
            json = array.getJSONObject(i);

            //Adding data to the superhero object
            recyclerviewList.setImage_path(json.getString(Config.TAG_IMAGE_URL));
            recyclerviewList.setImage_name(json.getString(Config.TAG_NAME));
        } catch (JSONException e) {
            e.printStackTrace();
        }
        //Adding the superhero object to the list
        listSuperHeroes.add(recyclerviewList);
    }

    //Notifying the adapter that data has been added or changed
    adapter.notifyDataSetChanged();
}

//This method would check that the recyclerview scroll has reached the bottom or not
private boolean isLastItemDisplaying(RecyclerView recyclerView) {
    if (recyclerView.getAdapter().getItemCount() != 0) {
        int lastVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
        if (lastVisibleItemPosition != RecyclerView.NO_POSITION && lastVisibleItemPosition == recyclerView.getAdapter().getItemCount() - 1)
            return true;
    }
    return false;
}

//Overriden method to detect scrolling
@Override
public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
    //Ifscrolled at last then
    if (isLastItemDisplaying(recyclerView)) {
        //Calling the method getdata again
        getData();
    }
}

如何使用volley删除recyclerview中的项目？

2 个答案: