Question

我已经从android中的mysql中检索数据并在循环视图中显示它。现在我想为检索到的信息添加onclick监听器。这里的代码可用https://www.simplifiedcoding.net/retrieve-data-mysql-database-android/

现在我想添加onclick监听器来检索信息。使用排球。

public class Product {
    private int id;
    private String title;
    private String shortdesc;
    private double rating;
    private double price;
    private String image;

    public Product(int id, String title, String shortdesc, double rating, double price, String image) {
        this.id = id;
        this.title = title;
        this.shortdesc = shortdesc;
        this.rating = rating;
        this.price = price;
        this.image = image;
    }

    public int getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }

    public String getShortdesc() {
        return shortdesc;
    }

    public double getRating() {
        return rating;
    }

    public double getPrice() {
        return price;
    }

    public String getImage() {
        return image;
    }
}

产品适配器

public class ProductsAdapter extends             
RecyclerView.Adapter<ProductsAdapter.ProductViewHolder> {

    private Context mCtx;
    private List<Product> productList;

    public ProductsAdapter(Context mCtx, List<Product> productList) {
        this.mCtx = mCtx;
        this.productList = productList;
    }

    @Override
    public ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(mCtx);
        View view = inflater.inflate(R.layout.product_list, null);
        return new ProductViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ProductViewHolder holder, int position) {
        Product product = productList.get(position);

        //loading the image
        Glide.with(mCtx)
                .load(product.getImage())
                .into(holder.imageView);

        holder.textViewTitle.setText(product.getTitle());
        holder.textViewShortDesc.setText(product.getShortdesc());
        holder.textViewRating.setText(String.valueOf(product.getRating()));
        holder.textViewPrice.setText(String.valueOf(product.getPrice()));
    }

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

    class ProductViewHolder extends RecyclerView.ViewHolder {

        TextView textViewTitle, textViewShortDesc, textViewRating, textViewPrice;
        ImageView imageView;

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

            textViewTitle = itemView.findViewById(R.id.textViewTitle);
            textViewShortDesc = itemView.findViewById(R.id.textViewShortDesc);
            textViewRating = itemView.findViewById(R.id.textViewRating);
            textViewPrice = itemView.findViewById(R.id.textViewPrice);
            imageView = itemView.findViewById(R.id.imageView);
        }
    }
}

主要活动

public class MainActivity extends AppCompatActivity {

    //this is the JSON Data URL
    //make sure you are using the correct ip else it will not work
    private static final String URL_PRODUCTS = "http://192.168.101.1/MyApi/Api.php";

    //a list to store all the products
    List<Product> productList;

    //the recyclerview
    RecyclerView recyclerView;


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

        //getting the recyclerview from xml 
        recyclerView = findViewById(R.id.recylcerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

        //initializing the productlist
        productList = new ArrayList<>();

        //this method will fetch and parse json 
        //to display it in recyclerview
        loadProducts();
    }

    private void loadProducts() {

        /*
        * Creating a String Request
        * The request type is GET defined by first parameter
        * The URL is defined in the second parameter
        * Then we have a Response Listener and a Error Listener
        * In response listener we will get the JSON response as a String
        * */
        StringRequest stringRequest = new StringRequest(Request.Method.GET, URL_PRODUCTS,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        try {
                            //converting the string to json array object
                            JSONArray array = new JSONArray(response);

                            //traversing through all the object
                            for (int i = 0; i < array.length(); i++) {

                                //getting product object from json array
                                JSONObject product = array.getJSONObject(i);

                                //adding the product to product list
                                productList.add(new Product(
                                        product.getInt("id"),
                                        product.getString("title"),
                                        product.getString("shortdesc"),
                                        product.getDouble("rating"),
                                        product.getDouble("price"),
                                        product.getString("image")
                                ));
                            }

                            //creating adapter object and setting it to recyclerview
                            ProductsAdapter adapter = new ProductsAdapter(MainActivity.this, productList);
                            recyclerView.setAdapter(adapter);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                });

        //adding our stringrequest to queue 
        Volley.newRequestQueue(this).add(stringRequest);
    }
}

的Json

[{"id":1,"title":"abc","shortdesc":"dis","rating":1,"price":1,"image":"aa"},
{"id":2,"title":"def","shortdesc":"abc","rating":3,"price":1000,"image":"abc"}]

Answer 1

您正在尝试将以下UI代码更新为线程，这就是它给出错误的原因。

ProductsAdapter adapter = new ProductsAdapter(MainActivity.this, productList);
recyclerView.setAdapter(adapter);

上面的行是onResponse()方法，它在工作线程中执行。

您只需在UI代码中编写这些行，而在onResponse()方法中，只需调用其notifyDataSetChanged()方法即可刷新适配器。

解决方案：

在loadProducts();方法之前写下以下行。

 ProductsAdapter adapter = new ProductsAdapter(MainActivity.this, productList);
 recyclerView.setAdapter(adapter);

在onResponse()方法之后，写下

 adapter.notifyDataSetChanged();

Answer 2

用这个替换你的ProductViewHolder课程.......它工作正常

class ProductViewHolder extends RecyclerView.ViewHolder {


        TextView textViewTitle, textViewShortDesc, textViewRating, textViewPrice;
        ImageView imageView;

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

            textViewTitle = itemView.findViewById(R.id.textViewTitle);
            textViewShortDesc = itemView.findViewById(R.id.textViewShortDesc);
            textViewRating = itemView.findViewById(R.id.textViewRating);
            textViewPrice = itemView.findViewById(R.id.textViewPrice);
            imageView = itemView.findViewById(R.id.imageView); 
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent =  new Intent(mCtx, YourActivity.class);
                    mCtx.startActivity(intent);
                }
            });
        }
    }

Answer 3

@Override
public void onBindViewHolder(ProductViewHolder holder, int position) {
    Product product = productList.get(position);

    //loading the image
    Glide.with(mCtx)
            .load(product.getImage())
            .into(holder.imageView);

    holder.textViewTitle.setText(product.getTitle());
    holder.textViewShortDesc.setText(product.getShortdesc());
    holder.textViewRating.setText(String.valueOf(product.getRating()));
    holder.textViewPrice.setText(String.valueOf(product.getPrice()));

    holder.itemView.setOnClickListener(new View.OnClickListener() {
      @Override public void onClick(View view) {

       //enter code here
      }
    });
}

android从mysql中检索数据并将其呈现在recycleview中并添加事件

3 个答案: