Android 未使用listview中的数据填充MainActivity
我正试图从中填充我的listview 编译和运行应用程序时没有错误,但只有一个空白的MainActivity。这是我的项目代码 主要活动:Android 未使用listview中的数据填充MainActivity,android,listview,Android,Listview,我正试图从中填充我的listview 编译和运行应用程序时没有错误,但只有一个空白的MainActivity。这是我的项目代码 主要活动: package com.example.szen95.meddict; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.view.MenuItem; public class MainActivity extends Ac
package com.example.szen95.meddict;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new SearchFragment())
.commit();
}
getSupportActionBar().setElevation(0f);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
搜索片段:
package com.example.szen95.meddict;
/**
* Created by szen95 on 6/15/15.
*/
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.SimpleAdapter;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
/**
* A placeholder fragment containing a simple view.
*/
public class SearchFragment extends Fragment {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://dailymed.nlm.nih.gov/dailymed/services/v2/drugclasses.json";
// JSON Node names
private static final String TAG_DATA = "data";
private static final String TAG_CODE = "code";
private static final String TAG_CODING_SYSTEM = "codingSystem";
private static final String TAG_TYPE = "type";
private static final String TAG_NAME = "name";
// contacts JSONArray
JSONArray data = null;
// ArrayAdapter<String> mConditionsAdapter;
public SearchFragment() {
}
ArrayList<HashMap<String, String>> dataList = new ArrayList<HashMap<String, String>>();
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
// Retrieving the currently selected item number
// int position = getArguments().getInt("position");
// Creating view correspoding to the fragment
View v = inflater.inflate(R.layout.fragment_main, container, false);
new GetData().execute();
return v;
}
/**
* Async task class to get json by making HTTP call
* */
private class GetData extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
//
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
data = jsonObj.getJSONArray(TAG_DATA);
// looping through All Contacts
for (int i = 0; i < data.length(); i++) {
JSONObject c = data.getJSONObject(i);
String code = c.getString(TAG_CODE);
String codingSystem = c.getString(TAG_CODING_SYSTEM);
String type = c.getString(TAG_TYPE);
String name = c.getString(TAG_NAME);
// tmp hashmap for single contact
HashMap<String, String> data = new HashMap<String, String>();
// adding each child node to HashMap key => value
data.put(TAG_CODE, code);
data.put(TAG_CODING_SYSTEM, codingSystem);
data.put(TAG_TYPE, type);
data.put(TAG_NAME, name);
// adding contact to contact list
dataList.add(data);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
SimpleAdapter adapter = new SimpleAdapter(getActivity(), dataList,
R.layout.list_item_search, new String[] { TAG_NAME, TAG_CODE}, new int[] { R.id.name,
R.id.code});
setListAdapter(adapter);
}
}
private void setListAdapter(SimpleAdapter adapter) {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_main, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_refresh) {
// FetchDataTask defTask = new FetchDataTask();
// defTask.execute();
return true;
}
return super.onOptionsItemSelected(item);
}
}
package com.example.szen95.meddict;
/**
*由szen95于2015年6月15日创建。
*/
导入android.app.ProgressDialog;
导入android.os.AsyncTask;
导入android.os.Bundle;
导入android.support.v4.app.Fragment;
导入android.util.Log;
导入android.view.LayoutInflater;
导入android.view.Menu;
导入android.view.MenuInflater;
导入android.view.MenuItem;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.simpledapter;
导入org.json.JSONArray;
导入org.json.JSONException;
导入org.json.JSONObject;
导入java.util.ArrayList;
导入java.util.HashMap;
/**
*包含简单视图的占位符片段。
*/
公共类SearchFragment扩展了片段{
私人对话;
//获取联系人JSON的URL
专用静态字符串url=”http://dailymed.nlm.nih.gov/dailymed/services/v2/drugclasses.json";
//JSON节点名称
私有静态最终字符串标记_DATA=“DATA”;
私有静态最终字符串标记\u CODE=“CODE”;
私有静态最终字符串标记\u编码\u SYSTEM=“codingSystem”;
私有静态最终字符串标记\u TYPE=“TYPE”;
私有静态最终字符串标记_NAME=“NAME”;
//联系JSONArray
JSONArray数据=null;
//阵列适配器mcconditionsadapter;
公共搜索片段(){
}
ArrayList dataList=新的ArrayList();
创建视图上的公共视图(更平坦的充气机,
视图组容器,
Bundle savedInstanceState){
//正在检索当前选定的项目编号
//int position=getArguments().getInt(“position”);
//创建与片段对应的视图
视图v=充气机。充气(右布局图。主容器碎片,假);
新建GetData().execute();
返回v;
}
/**
*异步任务类通过HTTP调用获取json
* */
私有类GetData扩展异步任务{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
//显示进度对话框
pDialog=newprogressdialog(getActivity());
//
setMessage(“请稍候…”);
pDialog.setCancelable(假);
pDialog.show();
}
@凌驾
受保护的Void doInBackground(Void…arg0){
//创建服务处理程序类实例
ServiceHandler sh=新的ServiceHandler();
//向url发出请求并获得响应
字符串jsonStr=sh.makeServiceCall(url,ServiceHandler.GET);
Log.d(“响应:”、“>”+jsonStr);
if(jsonStr!=null){
试一试{
JSONObject jsonObj=新的JSONObject(jsonStr);
//获取JSON数组节点
data=jsonObj.getJSONArray(TAG_数据);
//通过所有触点循环
对于(int i=0;ivalue
数据输入(标签代码、代码);
数据输入(标签编码系统、编码系统);
数据输入(标签类型,类型);
数据输入(标签名称、名称);
//将联系人添加到联系人列表
dataList.add(数据);
}
}捕获(JSONException e){
e、 printStackTrace();
}
}否则{
Log.e(“ServiceHandler”,“无法从url获取任何数据”);
}
返回null;
}
@凌驾
受保护的void onPostExecute(void结果){
super.onPostExecute(结果);
//关闭进度对话框
if(pDialog.isShowing())
pDialog.disclose();
/**
*将解析的JSON数据更新到ListView中
* */
SimpleAdapter=新SimpleAdapter(getActivity(),dataList,
R.layout.list_item_search,新字符串[]{TAG_NAME,TAG_CODE},新int[]{R.id.NAME,
R.id.code});
setListAdapter(适配器);
}
}
私有void setListAdapter(SimpleAdapter适配器){
}
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
设置选项菜单(真);
}
@凌驾
创建选项菜单(菜单菜单,菜单充气机){
充气机。充气(右菜单。主菜单,菜单);
}
@凌驾
公共布尔值onOptionsItemSelected(菜单项项){
int id=item.getItemId();
if(id==R.id.action\u刷新){
//FetchDataTask defTask=新建FetchDataTask();
//defTask.execute();
返回true;
}
返回super.onOptionsItemSelected(项目);
}
}
以下两件事可以解决您的问题-
private void setListAdapter(SimpleAdapter adapter) {
}
尝试调用适配器。notifyDataSetChanged()在调用异步类之前声明并初始化listview。首先初始化listview,然后将setListAdapter(适配器)更改为yourlistview.setAdapter(适配器);感谢