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我的ListViewAdapter类中得到了NPE错误。我做了一个自定义ListViewAdapter，但它不工作。为什么？NPE自定义ListView适配器
这里的代码和日志错误文件：
12-13 15:57:53.859: E/AndroidRuntime(22065): FATAL EXCEPTION: main
12-13 15:57:53.859: E/AndroidRuntime(22065): java.lang.NullPointerException
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.LayoutInflater.from(LayoutInflater.java:211)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.inflate(View.java:16803)
12-13 15:57:53.859: E/AndroidRuntime(22065): at com.prjma.lovertech.adapter.ListViewAdapter.getView(ListViewAdapter.java:60)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.AbsListView.obtainView(AbsListView.java:2177)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.ListView.measureHeightOfChildren(ListView.java:1247)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.ListView.onMeasure(ListView.java:1159)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:651)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
12-13 15:57:53.859: E/AndroidRuntime(22065): at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:302)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
12-13 15:57:53.859: E/AndroidRuntime(22065): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.View.measure(View.java:15848)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.Choreographer.doFrame(Choreographer.java:532)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.os.Handler.handleCallback(Handler.java:730)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.os.Handler.dispatchMessage(Handler.java:92)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.os.Looper.loop(Looper.java:137)
12-13 15:57:53.859: E/AndroidRuntime(22065): at android.app.ActivityThread.main(ActivityThread.java:5103)
12-13 15:57:53.859: E/AndroidRuntime(22065): at java.lang.reflect.Method.invokeNative(Native Method)
12-13 15:57:53.859: E/AndroidRuntime(22065): at java.lang.reflect.Method.invoke(Method.java:525)
12-13 15:57:53.859: E/AndroidRuntime(22065): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-13 15:57:53.859: E/AndroidRuntime(22065): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-13 15:57:53.859: E/AndroidRuntime(22065): at dalvik.system.NativeStart.main(Native Method)
ListViewAdaptr类：
package com.prjma.lovertech.adapter;
import java.util.ArrayList;
import java.util.HashMap;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import com.prjma.lovertech.R;
import com.prjma.lovertech.model.Item;
public class ListViewAdapter extends ArrayAdapter<String> {
private static LayoutInflater inflater = null;
public Context context;
public int layoutResourceId;
public ArrayList<HashMap<String, String>> items;
//public ImageLoader imageLoader;
public ListViewAdapter(Context context, int layoutResourceId) {
super(context, layoutResourceId);
// TODO Auto-generated constructor stub
Log.i("ListViewAdapter", "1");
}
public ListViewAdapter(Context context, int listviewItemRow, ArrayList<HashMap<String, String>> items) {
// TODO Auto-generated constructor stub
super(context, listviewItemRow);
this.items = items;
Log.i("ListViewAdapter constructor Context ", "Context1");
}
public int getCount() {
return items.size();
}
public Item getItem(Item position) {
return position;
}
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
Log.i("getView", "getView");
if (row == null) {
inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.listview_item_row, null);
}
Log.i("1", Boolean.toString(items.isEmpty()));
HashMap<String, String> p = items.get(position);
if (p != null) {
//ImageView listImage = (ImageView)row.findViewById(R.id.list_image);
TextView scadenza = (TextView)row.findViewById(R.id.tvScadenza);
TextView prezzo = (TextView)row.findViewById(R.id.tvPrezzo);
TextView followers = (TextView)row.findViewById(R.id.tvFollowers);
/*
if (listImage != null) {
listImage.animate();
}
*/
if (scadenza != null) {
scadenza.setText(p.get("scadenza"));
}
if (prezzo != null) {
prezzo.setText(p.get("prezzo"));
}
if (followers != null) {
followers.setText(p.get("followers"));
}
}
return row;
}
}
片段类：
package com.prjma.lovertech.fragment;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Fragment;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import com.prjma.lovertech.R;
import com.prjma.lovertech.adapter.ListViewAdapter;
import com.prjma.lovertech.util.JSONParser;
public class VendiFragment extends Fragment {
public ListView listView;
public ListViewAdapter adapter;
/**
* Keep track of the login task to ensure we can cancel it if requested.
*/
private DownloadTask mDownloadTask = null;
public ArrayList<HashMap<String, String>> items;
private static String URL = ".......";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_vendi, container, false);
// now you must initialize your list view
listView = (ListView) rootView.findViewById(R.id.listViewVendi);
items = new ArrayList<HashMap<String, String>>();
mDownloadTask = new DownloadTask();
mDownloadTask.execute((Void) null);
return rootView;
}
/**
* Represents an asynchronous login/registration task used to authenticate
* the user.
*/
public class DownloadTask extends AsyncTask<Void, Void, Boolean> {
@Override
protected Boolean doInBackground(Void... params) {
// TODO: attempt authentication against a network service.
//prendi tutti gli id dal webserver
ArrayList<Long> ids = search();
//per ogni id prendi l'elemento
for(int i=0; i < ids.size() - 1; i++){
getItem(ids.get(i));
}
return true;
}
@Override
protected void onPostExecute(final Boolean success) {
mDownloadTask = null;
// dismiss the dialog after getting all products
//showProgress(false);
// updating UI from Background Thread
getActivity().runOnUiThread(new Runnable() {
public void run() {
//Updating parsed JSON data into ListView
Log.i("onPostExecute items size", Integer.toString(items.size()));
ListViewAdapter adapter = new ListViewAdapter(getActivity(),R.layout.listview_item_row, items);
// updating listview
//adapter.notifyDataSetChanged();
listView.setAdapter(adapter);
}
});
}
@Override
protected void onCancelled() {
mDownloadTask = null;
//showProgress(false);
}
public ArrayList<Long> search(){
// Building Parameters for search
List<NameValuePair> parameters = new ArrayList<NameValuePair>();
parameters.add(new BasicNameValuePair("secret", "......"));
parameters.add(new BasicNameValuePair("category", ""));
parameters.add(new BasicNameValuePair("latitude", ""));
parameters.add(new BasicNameValuePair("longitude", ""));
parameters.add(new BasicNameValuePair("radius", ""));
parameters.add(new BasicNameValuePair("keywords", ""));
parameters.add(new BasicNameValuePair("order", ""));
parameters.add(new BasicNameValuePair("state", "2"));
JSONObject obj = JSONParser.getJSONFromUrl(URL + "search", parameters);
ArrayList<Long> ids = new ArrayList<Long>();
// check for service response
try {
String firstItem = obj.getString("items");
String[] values = firstItem.split("\\|");
ArrayList<Long> longs = new ArrayList<Long>();
for(int i=0; i < values.length; i++){
longs.add(Long.parseLong(values[i]));
}
String status = obj.getString("status");
Log.i("status", status);
if (status.equals("0")){
for (int i = 0; i < longs.size() - 1; i++) {
if (i == 0) {
ids.add(longs.get(i));
}
ids.add(longs.get(0) - longs.get(i + 1));
}
} else {
Log.e("error in search", "status = " + status);
}
} catch (JSONException e) {
e.printStackTrace();
}
return ids;
}
public void getItem(long ids){
// Building Parameters for search
Log.i("itemid", Long.toString(ids));
List<NameValuePair> parameters = new ArrayList<NameValuePair>();
parameters.add(new BasicNameValuePair("secret", "......"));
parameters.add(new BasicNameValuePair("itemid", Long.toString(ids)));
parameters.add(new BasicNameValuePair("details", "4"));
JSONObject obj = JSONParser.getJSONFromUrl(URL + "getitem", parameters);
// check for service response
try {
String status = obj.getString("status");
Log.i("status", status);
if (status.equals("0")){
String price = obj.getString("price");
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put("scadenza", obj.getString("sec2end"));
map.put("prezzo", obj.getString("price"));
map.put("followers", obj.getString("pop"));
// adding HashList to ArrayList
items.add(map);
Log.i("price", price);
} else {
Log.e("error in getItem", "status = " + status);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
你的权利，谢谢你！ – Pheonix7