将数据从URL显示到列表视图 [英] Displaying data from URL into listview
问题描述
我创建了一个应用程序，当我从URL显示数据时，使用JSON数组请求从URL获取数据.
I have created an app which fetches data from a URL using a JSON array request when I display the data from URL like this:
如何在列表视图中显示此数据?这是我的代码:
how can I show this data in a listview? Here is my code:
public class JsonRequestActivity extends Activity implements OnClickListener {
private String TAG = JsonRequestActivity.class.getSimpleName();
private Button btnJsonObj, btnJsonArray;
private TextView msgResponse;
private ProgressDialog pDialog;
// These tags will be used to cancel the requests
private String tag_json_obj = "jobj_req", tag_json_arry = "jarray_req";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_json);
btnJsonObj = (Button) findViewById(R.id.btnJsonObj);
btnJsonArray = (Button) findViewById(R.id.btnJsonArray);
msgResponse = (TextView) findViewById(R.id.msgResponse);
pDialog = new ProgressDialog(this);
pDialog.setMessage("Loading...");
pDialog.setCancelable(false);
btnJsonObj.setOnClickListener(this);
btnJsonArray.setOnClickListener(this);
}
private void showProgressDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hideProgressDialog() {
if (pDialog.isShowing())
pDialog.hide();
}
/**
* Making json object request
* */
private void makeJsonObjReq() {
showProgressDialog();
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET,
Const.URL_JSON_OBJECT, null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d(TAG, response.toString());
msgResponse.setText(response.toString());
hideProgressDialog();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
hideProgressDialog();
}
}) {
/**
* Passing some request headers
* */
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/json");
return headers;
}
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("name", "Androidhive");
params.put("email", "abc@androidhive.info");
params.put("pass", "password123");
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(jsonObjReq,
tag_json_obj);
// Cancelling request
// ApplicationController.getInstance().getRequestQueue().cancelAll(tag_json_obj);
}
/**
* Making json array request
* */
private void makeJsonArryReq() {
showProgressDialog();
JsonArrayRequest req = new JsonArrayRequest(Const.URL_JSON_ARRAY,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
msgResponse.setText(response.toString());
hideProgressDialog();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
hideProgressDialog();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(req,
tag_json_arry);
// Cancelling request
// ApplicationController.getInstance().getRequestQueue().cancelAll(tag_json_arry);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnJsonObj:
makeJsonObjReq();
break;
case R.id.btnJsonArray:
makeJsonArryReq();
break;
}
}
}
这是我正在使用的URL
And this is the URL I am using
http://api.androidhive.info/volley/person_array.json
推荐答案
您的回答是这样的:
[
{
"name": "Ravi Tamada",
"email": "ravi8x@gmail.com",
"phone": {
"home": "08947 000000",
"mobile": "9999999999"
}
},
{
"name": "Tommy",
"email": "tommy@gmail.com",
"phone": {
"home": "08946 000000",
"mobile": "0000000000"
}
}
]
这里是json数组.您可以通过以下方式对其进行解析:
Here it is json array. You can parse it this way:
创建一个Java对象类.您的课程是这样的:
Create a java object class. Your class is like this:
您的电话实体在这里:
import com.google.gson.annotations.SerializedName;
public class PhoneObject{
@SerializedName("home")
public String home;
@SerializedName("mobile")
public String mobile;
}
您的用户对象是
import com.google.gson.annotations.SerializedName;
public class UserObject{
@SerializedName("name")
public String name;
@SerializedName("email")
public String email;
@SerializedName("phone")
public PhoneObject phone;
public UserObject(){
phone=new Phone();
}
}
现在在onResponse回调中使用以下代码行:
Now in your onResponse callback use this line of code:
Type listType = new TypeToken<List<UserObject>>() {}.getType();
List<UserObject> yourList = new Gson().fromJson(response.toString(), listType);
现在您在yourList中有UserObject List.下一步是创建一个ListView并将其初始化.创建一个适配器，设置其项目布局，并使该项目的数据无效.
Now you have UserObject List in yourList. Next stage is create a ListView and initialize it. Create an adapter , set it's item layout and invalidate data of it's item.
假设您的ListView是这样的:
Suppose your ListView is like this:
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="#555"
android:dividerHeight="1dp"
android:listSelector="#000" />
和您的列表项行如下:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#fff"
android:padding="8dp" >
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:textStyle="bold" />
</RelativeLayout>
现在您的适配器会这样:
Now Your Adapter will like this:
public class CustomListAdapter extends BaseAdapter {
private Context activity;
private LayoutInflater inflater;
private List<UserObject> items;
public CustomListAdapter(Context activity, List<UserObject> items) {
this.activity = activity;
this.items = items;
}
@Override
public int getCount() {
return items.size();
}
@Override
public Object getItem(int location) {
return items.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_row, null);
TextView name = (TextView) convertView.findViewById(R.id.name);
// getting movie data for the row
UserObject m = items.get(position);
name.setText(m.name);
return convertView;
}
}
现在，您只需在onResponse()回调中以这种方式调用
Now you just call this way in onResponse() callback
CustomListAdapter adapter = new CustomListAdapter(this, yourList);
listView.setAdapter(adapter);
为什么选择Java对象
您有一个json数组.它的单个对象是这样的:
You have a json Array. It's individual object is like this:
{
"name": "Ravi Tamada",
"email": "ravi8x@gmail.com",
"phone": {
"home": "08947 000000",
"mobile": "9999999999"
}
}
在这里，它是一个json对象，它包含字符串和标记，分别是"name"，"email"和一个Json Object标记"phone".
Here, it is a json object, it contains string's and tag's are "name", 'email', and an Json Object tag "phone".
因此，此对象包含一些字符串和一个json对象名称"phone".
So here this object contains some string and a json object name "phone".
在前面的讨论中，我创建了一个Java对象名称PhoneObject，它的标签是通过以下方式初始化的:
From previous discussion, I created a Java Object name PhoneObject it's tag's are initialized using this way:
@SerializedName("home")
public String home;
现在"phone"标签在主对象中.因此，我在该对象中创建了UserObject并初始化了PhoneObject.
Now "phone" tag is in main Object. So i created UserObject and initialized PhoneObject in that object.
注意:，您必须实现json结构，然后必须开始创建java对象.
Note: You have to realize the json structure and after that you have to start creating the java object.
全部完成.如果需要更多信息，请访问此处
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