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Android ListView和Volley(Android ListView and Volley)

 非常新的android和凌空（双重麻烦:)） 
 

 在尝试使用一组字符串的listview（它工作，我能够看到结果）和从这些在线测试API之一检索（它工作，我看到结果） 
 

 当我试图将两者结合起来时（来自凌空的响应，解析它并将其传递给适配器）并且没有任何显示。 有人会告诉我一些结合volley和listview的实用教程，或者帮助向我展示如何让适配器在listview中正确显示响应。 
 

 希望有人有时间帮忙。 
 

 我的Mainactivity.java 
 

package com.example.web.listviewexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONException;
import org.json.JSONObject;

public class MainActivity extends AppCompatActivity {
    //Array of strings...
    String[] mobileArray = {"Android", "Iphone", "Windows", "WebOs", "BlackBerry", "Max OS x"};

    TextView results;
    String JsonURL ="https://reqres.in/api/users/2";
    String data="";

    //define the volley request queue. It handles requests
    RequestQueue requestQueue;



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

        //get the listview that will communicate with the adapter
        ListView listexample = (ListView) findViewById(R.id.mobile_list);
        //prepare the adapter
        final ArrayAdapter adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
        //attach the adapter
        listexample.setAdapter(adapter);

        //Volley stuff --cricket_007 Stackoverflow.com answer
        final JsonObjectRequest obj= new JsonObjectRequest(Request.Method.GET, JsonURL, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    // parse the response
                    response = response.getJSONObject("data");

                    // add things to the adapter
                    adapter.add(response.toString());
                }
                    catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener(){
                @Override
                public  void onErrorResponse(VolleyError error){error.printStackTrace();
                }

            });

       Volley.newRequestQueue(this).add(obj);
        }
    }

 

 activity_main.xml中 
 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    >


    <ListView
    android:id="@+id/mobile_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    </ListView>

</LinearLayout

 

 
 
 activity_listview.xml 
 

 

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/label"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:textSize="25sp"
    android:padding="10dp"
    android:textStyle="bold">

</TextView>

 

 得到这个错误 在此处输入图像描述 

Very new to android and volley (double trouble :))
 

After trying the listview with an array of strings(it worked and I was able to see the result) and volley to retrieve from one of those online test api (it worked and I see the result) 
 

When I attempted to combine the two (the response from volley, parse it and pass it to the adapter) and nothing shows. Would someone kindly point me to some solid tutorial combining volley and listview or help to show me how to get the adapter to display the response correctly in the listview.
 

Hope someone out there with time to help. 
 

My Mainactivity.java
 

package com.example.web.listviewexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONException;
import org.json.JSONObject;

public class MainActivity extends AppCompatActivity {
    //Array of strings...
    String[] mobileArray = {"Android", "Iphone", "Windows", "WebOs", "BlackBerry", "Max OS x"};

    TextView results;
    String JsonURL ="https://reqres.in/api/users/2";
    String data="";

    //define the volley request queue. It handles requests
    RequestQueue requestQueue;



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

        //get the listview that will communicate with the adapter
        ListView listexample = (ListView) findViewById(R.id.mobile_list);
        //prepare the adapter
        final ArrayAdapter adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
        //attach the adapter
        listexample.setAdapter(adapter);

        //Volley stuff --cricket_007 Stackoverflow.com answer
        final JsonObjectRequest obj= new JsonObjectRequest(Request.Method.GET, JsonURL, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    // parse the response
                    response = response.getJSONObject("data");

                    // add things to the adapter
                    adapter.add(response.toString());
                }
                    catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener(){
                @Override
                public  void onErrorResponse(VolleyError error){error.printStackTrace();
                }

            });

       Volley.newRequestQueue(this).add(obj);
        }
    }

 

Activity_Main.xml
 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    >


    <ListView
    android:id="@+id/mobile_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    </ListView>

</LinearLayout

 

 
 
activity_listview.xml
 

 

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/label"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:textSize="25sp"
    android:padding="10dp"
    android:textStyle="bold">

</TextView>

 

getting this error enter image description here

原文：https://stackoverflow.com/questions/43288977
更新时间：2022-05-28 09:05

最满意答案

 如果您只想显示单击行中“文本”列的值，您应该能够执行以下操作： 
 

else if (dataGridView1.Columns[e.ColumnIndex].Name == "Edit")
{
    Form2 form = new Form2();
    form.textBox1.Text = ((DataGridView)sender).Rows[e.RowIndex].Cells["Text"].Value.ToString();
    form.Show();
    Hide();
}

 

 这会从名为“Text”的相关单元格中获取值，并将其放入新表单文本框的Text中（假设该文本框名为“textBox1”）。 
 

 请注意，对于此事件处理程序，发件人是单击的网格。 通过属性名称“dataGridView1”引用也是有效的，但我认为使用处理程序的参数是一种更好的形式。 

If you just want to show the value of the "Text" column from the row that was clicked, you should be able to do something like this:
 

else if (dataGridView1.Columns[e.ColumnIndex].Name == "Edit")
{
    Form2 form = new Form2();
    form.textBox1.Text = ((DataGridView)sender).Rows[e.RowIndex].Cells["Text"].Value.ToString();
    form.Show();
    Hide();
}

 

This grabs the value from the related cell called "Text" and puts in into the Text of the new form's textbox (assumes that textbox is called "textBox1".
 

Note for this event handler, the sender is the grid that was clicked on. It's also valid to reference by the property name "dataGridView1", but I think it's a little better form to use the handler's arguments.

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