我正在尝试构建一个填充 ListView 的异步任务。当我尝试使用 findViewBYId 设置我的 listView 时:
ListView lv = (ListView) ((View) c).findViewById(R.id.tastelist);
我收到这个错误:
Cannot cast from Context to View
我的整个异步任务类是:
public class GetTasteJSON extends AsyncTask
<String, Void, String> {
Context c;
public GetTasteJSON(Context context)
{
c = context;
}
@Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
return readJSONFeed(arg0[0]);
}
protected void onPostExecute(String result){
//decode json here
try{
JSONObject json = new JSONObject(result);
//acces listview
ListView lv = (ListView) ((View) c).findViewById(R.id.tastelist);
//make array list for beer
final List<BeerData> beerList = new ArrayList<BeerData>();
}
catch(Exception e){
}
}
public String readJSONFeed(String URL) {
StringBuilder stringBuilder = new StringBuilder();
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(URL);
try {
HttpResponse response = httpClient.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
}
inputStream.close();
} else {
Log.d("JSON", "Failed to download file");
}
} catch (Exception e) {
Log.d("readJSONFeed", e.getLocalizedMessage());
}
return stringBuilder.toString();
}
}
最佳答案
转换为
ListView lv = (ListView) ((Activity) c).findViewById(R.id.tastelist);
本例中的上下文应该是您的 Activity
关于android - 无法从我的异步任务访问我的 ListView ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17331620/