自定义 ListView 未填充 Android 中的项目

Question

我正在使用 JSON 进行解析。单击按钮 JSON 开始解析并填充列表视图。数据来自服务器，但列表视图未填充。代码甚至没有显示任何错误。请检查

public class MainActivity extends AppCompatActivity {

Button start;
ListView listView;
TextView textView;
RequestQueue requestQueue;
String[] deliverName = new String[100];
String[] deliverPrice = new String[100];
int[] deliverImage = {R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher,
        R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher,
        R.mipmap.ic_launcher, R.mipmap.ic_launcher,};
int total;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    start = (Button) findViewById(R.id.button);
    //textView = (TextView) findViewById(R.id.textView);
    requestQueue = Volley.newRequestQueue(this);
    listView = (ListView) findViewById(R.id.listView2);

    start.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://deliverit.co.in/test.php?tablename=shakestable",
                    new Response.Listener<JSONObject>() {
                        @Override
                        public void onResponse(JSONObject response) {
                            try {
                                JSONArray jsonArray = response.getJSONArray("products");
                                for (int i = 0; i < jsonArray.length(); i++) {
                                    JSONObject products = jsonArray.getJSONObject(i);
                                    deliverName[i] = products.getString("name");
                                    deliverPrice[i] = products.getString("price");
                                }
                                Adapter adapter = new Adapter(getBaseContext(), deliverName, deliverPrice, deliverImage);
                                listView.setAdapter(adapter);
                                Log.e("TESTTTT", deliverName[2]);
                            } catch (JSONException e) {
                                e.printStackTrace();
                            }
                        }
                    },
                    new Response.ErrorListener() {
                        @Override
                        public void onErrorResponse(VolleyError error) {
                            Toast.makeText(MainActivity.this, "ERROR\n" + error.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    }
            );
            requestQueue.add(jsonObjectRequest);
        }
    });
}
}

Adapter.java

public class Adapter extends ArrayAdapter<String> {

int[] imgs={};
String[] name={};
String[] price={};
Context c;
LayoutInflater inflater;
public Adapter(Context context, String[] name, String[] price, int[] imgs) {
    super(context, R.layout.movies_row_layout);

    this.c = context;
    this.name = name;
    this.price = price;
    this.imgs = imgs;
}

public class ViewHolder
{
    TextView deliver_name;
    TextView deliver_price;
    ImageView deliver_image;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if(convertView==null){
        inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.movies_row_layout, null);
    }
    //View Holder Object
    final ViewHolder holder = new ViewHolder();
    holder.deliver_name = (TextView) convertView.findViewById(R.id.DELIVERname);
    holder.deliver_price = (TextView) convertView.findViewById(R.id.DELIVERprice);
    holder.deliver_image = (ImageView) convertView.findViewById(R.id.movie_poster);

    //ASSIGN DATA
    holder.deliver_image.setImageResource(imgs[position]);
    holder.deliver_price.setText(price[position]);
    holder.deliver_name.setText(name[position]);

    return convertView;
}
}

Answer 1

创建自定义适配器时还需要重写适配器 class 的 getCount() 方法，该方法在 class:

中得到扩展

@Override
public int getCount() {
    return name.length;  // return data-source size from here
}

Answer 2

实际上，您应该在响应侦听器下方创建队列。我希望它会起作用。如果它不起作用，它可能源于您 php 方面。

喜欢

public class MainActivity extends AppCompatActivity {

Button start;
ListView listView;
TextView textView;
RequestQueue requestQueue;
String[] deliverName = new String[100];
String[] deliverPrice = new String[100];
int[] deliverImage = {R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher,
        R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher,
        R.mipmap.ic_launcher, R.mipmap.ic_launcher,};
int total;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    start = (Button) findViewById(R.id.button);
    //textView = (TextView) findViewById(R.id.textView);
    requestQueue = Volley.newRequestQueue(this);
    listView = (ListView) findViewById(R.id.listView2);

    start.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://deliverit.co.in/test.php?tablename=shakestable",
                    new Response.Listener<JSONObject>() {
                        @Override
                        public void onResponse(JSONObject response) {
                            try {
                                JSONArray jsonArray = response.getJSONArray("products");
                                for (int i = 0; i < jsonArray.length(); i++) {
                                    JSONObject products = jsonArray.getJSONObject(i);
                                    deliverName[i] = products.getString("name");
                                    deliverPrice[i] = products.getString("price");
                                }
                                Adapter adapter = new Adapter(getBaseContext(), deliverName, deliverPrice, deliverImage);
                                listView.setAdapter(adapter);
                                Log.e("TESTTTT", deliverName[2]);
                            } catch (JSONException e) {
                                e.printStackTrace();
                            }
                        }
                    },
                    new Response.ErrorListener() {
                        @Override
                        public void onErrorResponse(VolleyError error) {
                            Toast.makeText(MainActivity.this, "ERROR\n" + error.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    }
            );
             RequestQueue requestQueue =  Volley.newRequestQueue(this);
            requestQueue.add(jsonObjectRequest);
        }
    });
}
}

Answer 3

您从 ArrayAdapter 扩展了适配器，但没有向适配器添加任何项目。此外，您将 3 个不同的数组放入构造函数。我认为，正确的方法是从 BaseAdapter 扩展您的适配器。但是，您可以稍微修改一下构造函数：

public Adapter(Context context, String[] name, String[] price, int[] imgs) {
    super(context, R.layout.movies_row_layout,names);
                                            ^^^^^^^^^
...

并且您现有的适配器将工作。

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