我已经制作了一个 listview 应用程序，然后我创建了一个带有片段的新应用程序，并希望将 listview 实现到片段。但是当我这样做时，我遇到了一个奇怪的错误。
public class Fragment1 extends Fragment {
private ArrayList<FeedItem> feedList = null;
private ProgressBar progressbar = null;
private ListView feedListView = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.list_row_layout, container, false);
progressbar = (ProgressBar)rootView.findViewById(R.id.progressBar);
String url = "";
new DownloadFilesTask().execute(url);
return rootView;
}
public void updateList() {
feedListView= (ListView)getActivity().findViewById(R.id.custom_list);
feedListView.setVisibility(View.VISIBLE);
progressbar.setVisibility(View.GONE);
**feedListView.setAdapter(new CustomListAdapter(this, feedList));**
feedListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> a, View v, int position, long id) {
Object o = feedListView.getItemAtPosition(position);
FeedItem newsData = (FeedItem) o;
**Intent intent = new Intent(FeedListActivity.this, FeedDetailsActivity.class);**
intent.putExtra("feed", newsData);
startActivity(intent);
}
});
}
public class DownloadFilesTask extends AsyncTask<String, Integer, Void> {
@Override
protected void onProgressUpdate(Integer... values) {
}
@Override
protected void onPostExecute(Void result) {
if (null != feedList) {
updateList();
}
}
@Override
protected Void doInBackground(String... params) {
String url = params[0];
// getting JSON string from URL
JSONObject json = getJSONFromUrl(url);
//parsing json data
parseJson(json);
return null;
}
}
public JSONObject getJSONFromUrl(String url) {
InputStream is = null;
JSONObject jObj = null;
String json = null;
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
public void parseJson(JSONObject json) {
try {
// parsing json object
if (json.getString("status").equalsIgnoreCase("ok")) {
JSONArray posts = json.getJSONArray("posts");
feedList = new ArrayList<FeedItem>();
for (int i = 0; i < posts.length(); i++) {
JSONObject post = (JSONObject) posts.getJSONObject(i);
FeedItem item = new FeedItem();
item.setTitle(post.getString("title"));
item.setDate(post.getString("description"));
item.setId(post.getString("id"));
item.setUrl(post.getString("url"));
item.setContent(post.getString("description"));
JSONArray attachments = post.getJSONArray("attachments");
if (null != attachments && attachments.length() > 0) {
JSONObject attachment = attachments.getJSONObject(0);
if (attachment != null)
item.setAttachmentUrl(attachment.getString("url"));
}
feedList.add(item);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
问题出在这条线上
feedListView.setAdapter(new CustomListAdapter(this, feedList));
Intent intent = new Intent(FeedListActivity.this, FeedDetailsActivity.class);
此行有多个标记 - 行断点：Fragment1 [行：57] - updateList()
- The constructor CustomListAdapter(Fragment1, ArrayList<FeedItem>) is
undefined
No enclosing instance of the type FeedListActivity is accessible in scope
自定义列表适配器：
public class CustomListAdapter extends BaseAdapter {
private ArrayList<FeedItem> listData;
private LayoutInflater layoutInflater;
private Context mContext;
public CustomListAdapter(Context context, ArrayList<FeedItem> listData) {
this.listData = listData;
layoutInflater = LayoutInflater.from(context);
mContext = context;
}
@Override
public int getCount() {
return listData.size();
}
@Override
public Object getItem(int position) {
return listData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.list_row_layout, null);
holder = new ViewHolder();
holder.headlineView = (TextView) convertView.findViewById(R.id.title);
holder.reportedDateView = (TextView) convertView.findViewById(R.id.date);
holder.imageView = (ImageView) convertView.findViewById(R.id.thumbImage);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
FeedItem newsItem = (FeedItem) listData.get(position);
holder.headlineView.setText(newsItem.getTitle());
holder.reportedDateView.setText(newsItem.getDate());
if (holder.imageView != null) {
new ImageDownloaderTask(holder.imageView).execute(newsItem.getAttachmentUrl());
}
return convertView;
}
static class ViewHolder {
TextView headlineView;
TextView reportedDateView;
ImageView imageView;
}
}