Question

我的自定义列表视图没有显示任何数据，我尝试重新编码适配器和其他所有内容但没有骰子。

它甚至没有显示任何错误，这就是让我疯狂的原因哈哈。任何人都可以帮我调试我的代码。

这是我的活动：

private ListView listView;


private ArrayList<String> orderName;

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

    orderName = new ArrayList<>();

    ListView listView = (ListView) findViewById(R.id.listViewOrder);

    viewOrderAdapter adapter = new viewOrderAdapter(viewOrdersPage.this, orderName);
    listView.setAdapter(adapter);

    getBoxInformation();

}

  private void getBoxInformation() {
    final ProgressDialog loading = ProgressDialog.show(this, "GETTING BOX INFROMATION", "Processing Request...", false, false);
    String url = DATA_URL + textUsername.getText().toString().trim();
    StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            showJSON(response);
            loading.dismiss();
        }
    },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(viewOrdersPage.this, error.getMessage().toString(), Toast.LENGTH_LONG).show();
                }
            });
    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(stringRequest);
}
private void showJSON(String response) {
  String name = "";

    try {
        jsonObject = new JSONObject(response);
        result = jsonObject.getJSONArray(JSON_ARRAY);
        order = result.getJSONObject(0);
        name = order.getString(TAG_ORDERNAME);

        JSONArray jsonarray = new JSONArray(name);
        for (int i = 0; i < jsonarray.length(); i++) {
            JSONObject jsonobject = jsonarray.getJSONObject(i);
            names = jsonobject.getString("name");


            //THE TOAST DISPLAYS THE TEXT SO I KNOW THE CODE WORKS, EXCEPT THE LISTVIEW
            Toast.makeText(viewOrdersPage.this, names, Toast.LENGTH_LONG).show();

     orderName.add(names);

        }
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

这是Adapter类：

public class viewOrderAdapter extends BaseAdapter {

private Context context;

private ArrayList<String> orderName;


public viewOrderAdapter(Context context, ArrayList<String> orderName){
    this.context = context;
    this.orderName = orderName;

}

@Override
public int getCount() {
    return orderName.size();
}

@Override
public Object getItem(int position) {
    return orderName.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}


@Override
public View getView(final int position, View convertView, ViewGroup parent) {

    final View listView;
    final LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    listView = inflater.inflate(R.layout.view_orders_item, null);

    TextView name = (TextView) listView.findViewById(R.id.orderNames);


    name.setText(orderName.get(position));

    return listView;
}

}

提前感谢您的帮助！

Answer 1

问题：网络请求需要一些时间，但是当列表中没有数据时您正在创建适配器，因此您需要告诉适配器数据发生了变化

将onCreate引用移到private ArrayList<String> orderName; private viewOrderAdapter adapter ; // adapter reference @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_view_orders_page); orderName = new ArrayList<>(); ListView listView = (ListView) findViewById(R.id.listViewOrder); adapter = new viewOrderAdapter(viewOrdersPage.this, orderName); listView.setAdapter(adapter); getBoxInformation(); }

之外

adapter.notifyDataSetChanged()

然后在showJSON函数

的末尾添加adapter

或

您可以在listview功能结束时showJSON上创建并设置<!DOCTYPE html> <html> <body> <h2>JFinding all even numbers</h2> <p>Please input a starting number, ending number and step number:</p> Starting Number: <input id="start"> Ending Number: <input id="end"> Step by Number: <input id="step"> <button type="button" onclick="myFunction()">Submit</button> <p id="demo"></p> <script> function myFunction() { var start, end, step, text; var result = []; // Get the value of the start number with start var start = parseInt(document.getElementById("start").value); // Get the value of the end number with end var end = parseInt(document.getElementById("end").value); // Get the value of the step number with step var step = parseInt(document.getElementById("step").value); console.log('start', start); console.log('end', end); console.log('step', step); // If start, end, or step is Not a Number or step is not even or start is greater than end or step is greater than end or start and step are equal to end if (isNaN(start) || isNaN(end) || isNaN(step) || step % 2 !== 0 || start > end || step > end || step === end || start === end) { //display text for invalid input text = "Input not valid"; //display text to html page document.getElementById("demo").innerHTML = text; //else create a loop to find even numbers } else { if(start % 2 === 0){ for(var i = start; i <= end; i += step){ result.push(i); } } else { start += 1; for(var i = start; i <= end; i += step){ result.push(i); } } //sent the result to the html page document.getElementById("demo").innerHTML = result; } console.log(result); } </script> </body> </html>

Answer 2

这是活动：

    private ListView listView;


    private ArrayList<String> orderName;

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

        orderName = new ArrayList<>();

        ListView listView = (ListView) findViewById(R.id.listViewOrder);



        getBoxInformation();

    }

    private void setDataInList(){
    viewOrderAdapter adapter = new viewOrderAdapter(viewOrdersPage.this, orderName);
        listView.setAdapter(adapter);
    }

      private void getBoxInformation() {
        final ProgressDialog loading = ProgressDialog.show(this, "GETTING BOX INFROMATION", "Processing Request...", false, false);
        String url = DATA_URL + textUsername.getText().toString().trim();
        StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                showJSON(response);
                loading.dismiss();
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(viewOrdersPage.this, error.getMessage().toString(), Toast.LENGTH_LONG).show();
                    }
                });
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(stringRequest);
    }
    private void showJSON(String response) {
      String name = "";

        try {
            jsonObject = new JSONObject(response);
            result = jsonObject.getJSONArray(JSON_ARRAY);
            order = result.getJSONObject(0);
            name = order.getString(TAG_ORDERNAME);

            JSONArray jsonarray = new JSONArray(name);
            for (int i = 0; i < jsonarray.length(); i++) {
                JSONObject jsonobject = jsonarray.getJSONObject(i);
                names = jsonobject.getString("name");


                //THE TOAST DISPLAYS THE TEXT SO I KNOW THE CODE WORKS, EXCEPT THE LISTVIEW
                Toast.makeText(viewOrdersPage.this, names, Toast.LENGTH_LONG).show();

         orderName.add(names);

            }
if(orderName.size()>0){
setDataInList();
}
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

这是适配器类：

public class viewOrderAdapter extends BaseAdapter {

private Context context;

private ArrayList<String> orderName;


public viewOrderAdapter(Context context, ArrayList<String> orderName){
    this.context = context;
    this.orderName = orderName;

}

@Override
public int getCount() {
    return orderName.size();
}

@Override
public Object getItem(int position) {
    return orderName.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}


@Override
public View getView(final int position, View convertView, ViewGroup parent) {

    View listView;
     LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    listView = inflater.inflate(R.layout.view_orders_item, null);

    TextView name = (TextView) listView.findViewById(R.id.orderNames);


    name.setText(orderName.get(position));

    return listView;
}

自定义列表视图不显示数据

2 个答案: