我正在学习使用自定义适配器，我想我正朝着正确的方向前进，直到我遇到类Custom Adapter的构造函数的super方法有问题。你能找出背后的问题吗？ 在此之前，我使用简单适配器，但我想要更灵活地控制布局。 这是我的xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp">
<!-- Name Label -->
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Hello This is testing"
android:id="@+id/guid"
android:visibility="gone"/>
<TextView
android:id="@+id/name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textColor="#43bd00"
android:text="name:"
android:textStyle="bold"
android:visibility="gone"/>
<!-- Email label -->
<TextView
android:id="@+id/email"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:textColor="#acacac"
android:text="email"
android:textStyle="bold"
/>
<!-- Mobile number label -->
<TextView
android:id="@+id/mobile"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="left"
android:text="Mobile: "
android:textColor="#5d5d5d"
android:maxLines="1"/>
</LinearLayout>
这是我的片段类
public class NewsFragment extends Fragment{
private ProgressDialog pDialog;// Progress Dialog
ListView newsList;
ArrayList<HashMap<String, String>> postList; //Declare Array
private static String url = "http://wangeltmg.com/GKN_ADMIN/GET_POSTS/get_news.php";
GetNews.CustomAdapter CA;
// JSON Node names
private static final String TAG_ID = "id";
private static final String POST_ALLPOSTS = "posts";
private static final String POST_ID = "ID";
private static final String POST_TITLE = "post_title";
private static final String POST_CONTENT = "post_content";
private static final String GUID = "guid";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.news, container, false);
newsList = (ListView) view.findViewById(R.id.newsListView);
TextView topic = (TextView) view.findViewById(R.id.topic);
postList = new ArrayList<HashMap<String, String>>();
//Get arguments
Bundle args = getArguments();
String mytopic = args.getString("Topic");
//Set topic
topic.setText(mytopic.toUpperCase());
//Execute getContacts
new GetNews().execute();
newsList.setOnItemClickListener(new newsListClick());
return view;
}
public class newsListClick implements ListView.OnItemClickListener{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Log.d("News List","Clicked " + id);
android.support.v4.app.FragmentManager fragmentManager = getFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
SinglePost singleFrag = new SinglePost();
fragmentTransaction.replace(R.id.content_frame, singleFrag);
fragmentTransaction.commit();
}
}
//Async Task
private class GetNews 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("Strings","Checking Json");
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// contacts JSONArray
JSONArray posts = null;
// Getting JSON Array node
posts = jsonObj.getJSONArray(POST_ALLPOSTS);
// looping through All Contacts
for (int i = 0; i < posts.length(); i++) {
JSONObject c = posts.getJSONObject(i);
Log.d("Post->",posts.getJSONObject(i).toString());
String id = c.getString(POST_ID);
Log.d("Post->ID",id);
String post_title = c.getString(POST_TITLE);
String post_content = c.getString(POST_CONTENT);
String guid = c.getString(GUID);
Log.d("GUID->",guid);
//String gender = c.getString(TAG_GENDER);
// tmp hashmap for single post
HashMap<String, String> post = new HashMap<String, String>();
// adding each child node to HashMap key => value
post.put(POST_ID, id);
post.put(POST_TITLE, post_title);
post.put(POST_CONTENT, post_content);
post.put(GUID, guid);
// adding contact to contact list
postList.add(post);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
public void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
// Updating parsed JSON data into ListView
/*
ListAdapter adapter = new SimpleAdapter(getActivity(), postList, R.layout.list_item,
new String[] { POST_TITLE,POST_CONTENT, GUID },
new int[] {R.id.email, R.id.mobile, R.id.guid });
*/
CA = new CustomAdapter( getActivity(), R.layout.list_item, postList);
newsList.setAdapter(CA);
}
public class CustomAdapter extends ArrayAdapter<HashMap<String, String>>{
public CustomAdapter(Context context, int resource, ArrayList<HashMap<String, String>> objects) {
//something is wrong with super
super(context, resource, objects);
}
public View getView(int position, View convertView, ViewGroup Parent){
if(convertView == null){
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.list_item,null);
}
HashMap<String, String> objects = new HashMap<String, String>();
TextView thisview = (TextView) convertView.findViewById(R.id.email);
thisview.setText(objects.get(position).get(POST_TITLE));
return convertView;
}
}//
}
}
答案 0 :(得分：4)
更改此行
CA = new CustomAdapter(this, R.layout.list_item, postList);
到
CA = new CustomAdapter(getActivity(), R.layout.list_item, postList);
注意：在使用Fragment时，您应该将getActivity()用作Context。
另请注意，您使用的是HashMap<String,String>，因此ArrayAdapter将ArrayAdapter<HashMap<String, String>>而不是ArrayAdapter<String>。
答案 1 :(得分：2)
您正在扩展ArrayAdapter<String>并将ArrayList作为构造函数参数传递。它们都必须属于同一类型。
此外，您需要传递Context而不是您的asynctask GetNews。
您还可以查看BaseAdapter，您无需将任何数组作为构造函数参数传递。
答案 2 :(得分：2)
要扩展Piyush的答案，您还需要修改CustomAdapter构造函数
由此：
public CustomAdapter(GetNews context, ... ) { }
到这个
public CustomAdapter(Context context, ... ) { }
这是因为getActivity()将返回Activity，这是Context类的实例 - 不是GetNews的实例
答案 3 :(得分：1)
private ArrayList<HashMap<String, String>> mList;
public void setmList(ArrayList<HashMap<String, String>> mList) {
this.mList = mList;
}
public CustomAdapter(Context context, int resource) {
//something is wrong with super
super(context, resource);
}
并使用设置列表
初始化它CA = new CustomAdapter(getActivity, R.layout.list_item);
CA.setmList(yourlist);
不知道为什么超级三参数在这种情况下不起作用但它肯定会解决你的问题