在空指针异常的AutoComplete TextView中获取错误。
当我延长Activity然后它可以工作，但是当我扩展片段时，它不会显示AutocompleteTextView中的选项。
得到如下错误： -
E/Fail 3: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
这里有完整的代码： -
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
// don't look at this layout it's just a listView to show how to handle the keyboard
View view = inflater.inflate(R.layout.activity_add__visit, container, false);
session = new SessionManager(getActivity());
HashMap<String, String> user = session.getUserDetails();
uid = user.get(SessionManager.KEY_ID);
longi = (TextView)view. findViewById(R.id.longitude);
lat= (TextView)view. findViewById(R.id.latitude);
ac=(AutoCompleteTextView)view.findViewById(R.id.autoCompleteTextView1);
remarks = (EditText)view.findViewById(R.id.remarks);
submit=(Button)view.findViewById(R.id.submit);
new DownloadJSON().execute();
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
remark_detail = remarks.getText().toString();
id = ac.getText().toString();
latitude12=lat.getText().toString();
longitude12=longi.getText().toString();
if (id.equals(null) || id.equals(""))
{
Toast.makeText(getActivity(), "Please Select Party Name", Toast.LENGTH_LONG).show();
} else
{
GetCurrentGPSLocation gps = new GetCurrentGPSLocation(getActivity());
// check if GPS enabled
if (gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
// \n is for new line
lat.setText( ""+latitude);
longi.setText("" +longitude);
latitude12=lat.getText().toString();
longitude12=longi.getText().toString();
Toast.makeText(getActivity(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
longi.setVisibility(View.INVISIBLE);
lat.setVisibility(View.INVISIBLE);
} else {
// can't get location
// GPS or Network is not enabled
// Ask user to enable GPS/network in settings
gps.showSettingsAlert();
}
addvisitor();
//FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
//fragmentTransaction.replace(R.id.containerView,new Home()).commit();
}
}
});
return view;
}
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(getActivity());
mProgressDialog.setTitle("Please Wait");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... voids) {
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.wealinfotech.com/portal/autocomplete.php");
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
Log.e("Pass 1", "connection success ");
} catch (Exception e) {
Log.e("Fail 1", e.toString());
Toast.makeText(getActivity(), "Invalid IP Address", Toast.LENGTH_LONG).show();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
Log.e("Pass 2", "connection success ");
} catch (Exception e) {
Log.e("Fail 2", e.toString());
}
return null;
}
@Override
protected void onPostExecute(Void args) {
try {
JSONArray JA = new JSONArray(result);
JSONObject json = null;
final String[] str1 = new String[JA.length()];
final String[] str2 = new String[JA.length()];
for (int i = 0; i < JA.length(); i++) {
json = JA.getJSONObject(i);
str1[i] = json.getString("cl_pname");
str2[i] = json.getString("cl_wodcode");
}
final AutoCompleteTextView text = (AutoCompleteTextView)view. findViewById(R.id.autoCompleteTextView1);
final List<String> list = new ArrayList<String>();
for (int i = 0; i < str1.length; i++) {
list.add(str1[i]);
}
Collections.sort(list);
final ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(getActivity(), R.layout.my_list_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_list_item_1);
text.setThreshold(1);
text.setAdapter(dataAdapter);
text.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String selected_cl_pname = (String) parent.getItemAtPosition(position);
int index = Arrays.asList(str1).indexOf(selected_cl_pname);
String selected_cl_wodcode = str2[index];
wv1 = (WebView)view. findViewById(R.id.webView);
wv1.setWebViewClient(new MyBrowser());
wv1.loadUrl("http://www.wealinfotech.com/portal/on_target.php?cl_wodcode=" + selected_cl_wodcode);
wv1.getSettings().setLoadsImagesAutomatically(true);
wv1.getSettings().setJavaScriptEnabled(true);
wv1.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
Toast.makeText(getActivity(), (CharSequence) parent.getItemAtPosition(position), Toast.LENGTH_LONG).show();
Log.d("wt_wod_code", selected_cl_wodcode);
Log.d("wt_wod_sascode", str2[index]);
// Toast.makeText(getApplicationContext(), (CharSequence) parent.getItemAtPosition(position), Toast.LENGTH_LONG).show();
wt_wod_code1 = text.getText().toString();
wt_party1 = text.getText().toString();
}
});
} catch (Exception e) {
Log.e("Fail 3", e.toString());
mProgressDialog.dismiss();
}
}
答案 0 :(得分：0)
覆盖片段内的OnViewCreated和那里的查找ids
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
longi = (TextView)view.findViewById(R.id.longitude);
lat= (TextView)view.findViewById(R.id.latitude);
ac=(AutoCompleteTextView)view.findViewById(R.id.autoCompleteTextView1);
remarks = (EditText)view.findViewById(R.id.remarks);
submit=(Button)view.findViewById(R.id.submit);
}
答案 1 :(得分：0)
尝试替换：
final AutoCompleteTextView text = (AutoCompleteTextView) view.findViewById(R.id.autoCompleteTextView1);
使用：
final AutoCompleteTextView text = (AutoCompleteTextView) getView().findViewById(R.id.autoCompleteTextView1);
同样地：
wv1 = (WebView) view.findViewById(R.id.webView);
使用：
wv1 = (WebView) getView().findViewById(R.id.webView);
您可能正在使用实例变量view（在问题和示例粘贴代码中没有提及），在您尝试使用它时未初始化。
修改
强烈建议您在new DownloadJSON().execute();而不是onViewCreated()中致电onCreatView()。此解决方案可以正常工作，但只有在从服务器获取响应之前创建View时，如果网络太快而设备由于某种原因而变慢，则无法正常工作。