我正在运行Android应用程序，该应用程序从网站下载信息并在屏幕上打印包含该信息的列表。
然而，当它试图加载列表时，应用程序崩溃，我得到以下logcat：
04-15 23:32:41.946: I/Choreographer(2069): Skipped 40 frames! The application may be doing too much work on its main thread.
04-15 23:32:50.038: I/Choreographer(2069): Skipped 33 frames! The application may be doing too much work on its main thread.
04-15 23:32:52.096: I/DO IN BACKGROUD(2069): {"succeed":true,"user_id":362}
04-15 23:32:52.096: I/MESSAGE(2069): {"succeed":true,"user_id":362}
04-15 23:32:52.146: I/put Extra user id(2069): 362
04-15 23:32:56.256: I/dalvikvm-heap(2069): Grow heap (frag case) to 3.554MB for 635812-byte allocation
04-15 23:32:59.027: I/Connection(2069): true
04-15 23:32:59.257: I/Choreographer(2069): Skipped 79 frames! The application may be doing too much work on its main thread.
04-15 23:33:00.456: I/Choreographer(2069): Skipped 297 frames! The application may be doing too much work on its main thread.
04-15 23:33:01.447: I/Choreographer(2069): Skipped 229 frames! The application may be doing too much work on its main thread.
04-15 23:33:03.138: I/Choreographer(2069): Skipped 184 frames! The application may be doing too much work on its main thread.
04-15 23:33:03.856: I/Choreographer(2069): Skipped 186 frames! The application may be doing too much work on its main thread.
04-15 23:33:04.349: I/DO IN BACKGROUD(2069): { "supermercado": "La Salle - Curs Android II", "productos" : [ { "id" : 1, "fabricante" : "Nestlé", "nombre" : "NESQUIK", "precio" : 12.85, "stock" : 10 }, { "id" : 2, "fabricante" : "Coca-cola", "nombre" : "Coca-cola", "precio" : 3.21, "stock" : 150 }, { "id" : 3, "fabricante" : "Borges", "nombre" : "Aceite girasol 1L", "precio" : 1.88, "stock" : 0 }, { "id" : 4, "fabricante" : "Serpis", "nombre" : "Aceitunas rellenas de anchoa 160g", "precio" : 1.39, "stock" : 1523 }, { "id" : 5, "fabricante" : "Carretilla", "nombre" : "Pimientos piquillo ajillo 290g", "precio" : 2.25, "stock" : 14 }, { "id" : 6, "fabricante" : "Orlando", "nombre" : "Tomate frito con aceite de oliva virgen brik 390g", "precio" : 0.95, "stock" : 0 }, { "id" : 7, "fabricante" : "Kellogg's", "nombre" : "Cereales Special K chocolate 300g", "precio" : 2.39, "stock" : 152 }, { "id" : 8, "fabricante" : "Lu", "nombre" : "Galletas rellenas mini Principe 160g", "precio" : 1.59, "stock" : 29 }, { "id" : 9, "fabricante" : "Pascual", "nombre" : "Leche sin lactosa desnatada brik 1l", "precio" : 1.49, "stock" : 1596 }, { "id" : 10, "fabricante" : "Danone", "nombre" : "Danet vainilla 4x125g", "precio" : 1.90, "stock" : 856 }, { "id" : 11, "fabricante" : "Hornimans", "nombre" : "Infusueños 20 sobres", "precio" : 2.35, "stock" : 598 } ]}
04-15 23:33:04.516: I/Choreographer(2069): Skipped 169 frames! The application may be doing too much work on its main thread.
04-15 23:33:04.848: I/Choreographer(2069): Skipped 59 frames! The application may be doing too much work on its main thread.
04-15 23:33:05.188: I/On Post EXECUTE(2069): { "supermercado": "La Salle - Curs Android II", "productos" : [ { "id" : 1, "fabricante" : "Nestlé", "nombre" : "NESQUIK", "precio" : 12.85, "stock" : 10 }, { "id" : 2, "fabricante" : "Coca-cola", "nombre" : "Coca-cola", "precio" : 3.21, "stock" : 150 }, { "id" : 3, "fabricante" : "Borges", "nombre" : "Aceite girasol 1L", "precio" : 1.88, "stock" : 0 }, { "id" : 4, "fabricante" : "Serpis", "nombre" : "Aceitunas rellenas de anchoa 160g", "precio" : 1.39, "stock" : 1523 }, { "id" : 5, "fabricante" : "Carretilla", "nombre" : "Pimientos piquillo ajillo 290g", "precio" : 2.25, "stock" : 14 }, { "id" : 6, "fabricante" : "Orlando", "nombre" : "Tomate frito con aceite de oliva virgen brik 390g", "precio" : 0.95, "stock" : 0 }, { "id" : 7, "fabricante" : "Kellogg's", "nombre" : "Cereales Special K chocolate 300g", "precio" : 2.39, "stock" : 152 }, { "id" : 8, "fabricante" : "Lu", "nombre" : "Galletas rellenas mini Principe 160g", "precio" : 1.59, "stock" : 29 }, { "id" : 9, "fabricante" : "Pascual", "nombre" : "Leche sin lactosa desnatada brik 1l", "precio" : 1.49, "stock" : 1596 }, { "id" : 10, "fabricante" : "Danone", "nombre" : "Danet vainilla 4x125g", "precio" : 1.90, "stock" : 856 }, { "id" : 11, "fabricante" : "Hornimans", "nombre" : "Infusueños 20 sobres", "precio" : 2.35, "stock" : 598 } ]}
04-15 23:33:05.486: I/Write STORAGE(2069): { "supermercado": "La Salle - Curs Android II", "productos" : [ { "id" : 1, "fabricante" : "Nestlé", "nombre" : "NESQUIK", "precio" : 12.85, "stock" : 10 }, { "id" : 2, "fabricante" : "Coca-cola", "nombre" : "Coca-cola", "precio" : 3.21, "stock" : 150 }, { "id" : 3, "fabricante" : "Borges", "nombre" : "Aceite girasol 1L", "precio" : 1.88, "stock" : 0 }, { "id" : 4, "fabricante" : "Serpis", "nombre" : "Aceitunas rellenas de anchoa 160g", "precio" : 1.39, "stock" : 1523 }, { "id" : 5, "fabricante" : "Carretilla", "nombre" : "Pimientos piquillo ajillo 290g", "precio" : 2.25, "stock" : 14 }, { "id" : 6, "fabricante" : "Orlando", "nombre" : "Tomate frito con aceite de oliva virgen brik 390g", "precio" : 0.95, "stock" : 0 }, { "id" : 7, "fabricante" : "Kellogg's", "nombre" : "Cereales Special K chocolate 300g", "precio" : 2.39, "stock" : 152 }, { "id" : 8, "fabricante" : "Lu", "nombre" : "Galletas rellenas mini Principe 160g", "precio" : 1.59, "stock" : 29 }, { "id" : 9, "fabricante" : "Pascual", "nombre" : "Leche sin lactosa desnatada brik 1l", "precio" : 1.49, "stock" : 1596 }, { "id" : 10, "fabricante" : "Danone", "nombre" : "Danet vainilla 4x125g", "precio" : 1.90, "stock" : 856 }, { "id" : 11, "fabricante" : "Hornimans", "nombre" : "Infusueños 20 sobres", "precio" : 2.35, "stock" : 598 } ]}
04-15 23:33:07.027: W/dalvikvm(2069): threadid=1: thread exiting with uncaught exception (group=0x41465700)
04-15 23:33:07.266: E/AndroidRuntime(2069): FATAL EXCEPTION: main
04-15 23:33:07.266: E/AndroidRuntime(2069): java.lang.NullPointerException: println needs a message
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.util.Log.println_native(Native Method)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.util.Log.i(Log.java:159)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.example.shop.Tenda.refreshListByJson(Tenda.java:305)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.example.shop.Tenda.access$1(Tenda.java:302)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.example.shop.Tenda$LongAsyncTask.onPostExecute(Tenda.java:259)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.example.shop.Tenda$LongAsyncTask.onPostExecute(Tenda.java:1)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.os.AsyncTask.finish(AsyncTask.java:631)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.os.AsyncTask.access$600(AsyncTask.java:177)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.os.Handler.dispatchMessage(Handler.java:99)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.os.Looper.loop(Looper.java:137)
04-15 23:33:07.266: E/AndroidRuntime(2069): at android.app.ActivityThread.main(ActivityThread.java:5103)
04-15 23:33:07.266: E/AndroidRuntime(2069): at java.lang.reflect.Method.invokeNative(Native Method)
04-15 23:33:07.266: E/AndroidRuntime(2069): at java.lang.reflect.Method.invoke(Method.java:525)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
04-15 23:33:07.266: E/AndroidRuntime(2069): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-15 23:33:07.266: E/AndroidRuntime(2069): at dalvik.system.NativeStart.main(Native Method)
04-15 23:33:13.366: I/Process(2069): Sending signal. PID: 2069 SIG: 9
04-15 23:33:20.867: I/Choreographer(2098): Skipped 60 frames! The application may be doing too much work on its main thread.
以下是发生崩溃的活动：
Tenda.java
package com.example.shop;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import com.example.shop.SuperAdapter;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.text.InputType;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.NumberPicker;
import android.widget.TextView;
import android.widget.Toast;
public class Tenda extends Activity implements OnItemClickListener, LocationListener {
ProgressDialog lDialog;
String json_string;
SuperAdapter adapter_super;
int user_id;
private LocationManager locationManager;
public String provider;
private String lattitude , longitude;
/*************************************************/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tenda);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
init_conf();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.tenda, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.menu_update:
updateList();
return true;
case R.id.menu_search:
alert_search();
return true;
case R.id.menu_cancel:
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public void onItemClick(AdapterView<?> arg0, View view, int position, long arg3) {
TextView stock = (TextView) view.findViewById(R.id.list_product_stock);
int num_stock = Integer.parseInt(stock.getText().toString()) ;
if(num_stock!=0){
ArrayList<Super> productes=adapter_super.getItems_producte();
Super current_product= productes.get(position);
alert_buy(num_stock,current_product);
}
else
{
Toast.makeText(this, "OUT OF STOCK", Toast.LENGTH_LONG).show();
}
}
private void init_conf(){
Bundle extras = getIntent().getExtras();
user_id = extras.getInt("user_id");
Toast.makeText(this, "user id"+Integer.toString(user_id), Toast.LENGTH_LONG).show();
ListView lsv_producto = (ListView)findViewById(R.id.list_productes);
adapter_super = new SuperAdapter(Tenda.this,null);
lsv_producto.setAdapter(adapter_super);
lsv_producto.setOnItemClickListener(this);
updateList();
}
private void updateList(){
loading();
String url = "http://www.v2msoft.com/clientes/lasalle/curs-android/products.php?user_id="+user_id;
boolean is_con=is_connected();
if(is_con){
Log.i("Connection", "true");
AsyncTask(url);
Toast.makeText(this, "connected internet", Toast.LENGTH_LONG).show();
}
else{
json_string=storeRead();
refreshListByJson(json_string);
Toast.makeText(this, "not connected internet", Toast.LENGTH_LONG).show();
}
}
private void search(String text){
loading();
String url="http://www.v2msoft.com/clientes/lasalle/curs-android/search.php?user_id="+user_id+"&q="+text;
boolean is_con=is_connected();
if(is_con){
Log.i("search URL", url);
Toast.makeText(this, url, Toast.LENGTH_LONG).show();
searchAsyncTask(url);
}
else{
Toast.makeText(this, "NO CONNECTION", Toast.LENGTH_LONG).show();
}
}
private void buy(Super producte, int value){
int product_id= producte.getId();
String url="http://www.v2msoft.com/clientes/lasalle/curs-android/buy.php?user_id="+user_id+
"&product_id="+product_id+
"&items="+value+
"&lat="+1+
"&long="+1;
Toast.makeText(this, url, Toast.LENGTH_LONG).show();
}
private void AsyncTask(String url){
LongAsyncTask task = new LongAsyncTask();
task.execute(url);
}
private void searchAsyncTask(String url){
SearchAsyncTask task = new SearchAsyncTask();
task.execute(url);
}
public void alert_search(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Title");
final EditText input = new EditText(this);
input.setInputType(InputType.TYPE_CLASS_TEXT);
builder.setView(input);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String m_Text = input.getText().toString();
Toast.makeText(getApplicationContext(), m_Text, Toast.LENGTH_LONG).show();
search(m_Text);
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
}
public void alert_buy(int max_value,final Super producte){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("BUY");
final NumberPicker number= new NumberPicker(this);
number.setMaxValue(max_value);
number.setMinValue(0);
builder.setView(number);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
int value= number.getValue();
Toast.makeText(getApplicationContext(), value+"", Toast.LENGTH_LONG).show();
buy(producte,value);
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
}
/*************************ASYNC TASK************************/
public class LongAsyncTask extends AsyncTask<String,String,String>{
@Override
protected String doInBackground(String... url) {
String url_result= conect(url[0]);
Log.i("DO IN BACKGROUND", url_result);
return url_result;
}
protected void onPostExecute(String url_result) {
Log.i("On Post EXECUTE", url_result);
json_string= url_result;
storeWrite(json_string);
refreshListByJson(json_string);//line 259
}
}
public class SearchAsyncTask extends AsyncTask<String,String,String>{
@Override
protected String doInBackground(String... url) {
String url_result= conect(url[0]);
Log.i("Search result", url_result);
return url_result;
}
protected void onPostExecute(String url_result) {
Log.i("On Post EXECUTE SEARCH", url_result);
json_string= url_result;
Toast.makeText(getApplicationContext(), json_string, Toast.LENGTH_LONG).show();
refreshListByJson(json_string);
}
}
public class BuyAsyncTask extends AsyncTask<String,String,String>{
@Override
protected String doInBackground(String... url) {
String url_result= conect(url[0]);
Log.i("buy result", url_result);
return url_result;
}
protected void onPostExecute(String url_result) {
Log.i("On Post EXECUTE SEARCH", url_result);
json_string= url_result;
Toast.makeText(getApplicationContext(), json_string, Toast.LENGTH_LONG).show();
}
}
/*************************************************/
private void refreshListByJson(String json){//line 302
lDialog.dismiss();
Store store=Store.newStore(json);
Log.i("store-nom", store.getStore());//line 305
Log.i("store-producte", store.getProductos().toString());
adapter_super.setItems_producto(store.getProductos());
}
private void storeWrite(String data){
String FILENAME = "json_store";
FileOutputStream fos;
try {
fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.i("Write STORAGE", data);
}
private String storeRead(){
String FILENAME = "json_store";
FileInputStream fis;
StringBuilder fileContent = new StringBuilder();
try {
fis= openFileInput (FILENAME);
BufferedReader br= new BufferedReader(new InputStreamReader(fis));
String line;
while((line = br.readLine())!= null)
{
fileContent.append(line);
}
br.close();
fis.close();
Log.i("READ STORAGE", fileContent.toString());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return fileContent.toString();
}
public String conect(String url_string){
HttpURLConnection con = null;
BufferedReader reader= null;
try{
URL url = new URL(url_string);
con = (HttpURLConnection)url.openConnection();
reader= new BufferedReader(new InputStreamReader(con.getInputStream()));
String line ="";
StringBuffer responseBuffer = new StringBuffer();
while((line=reader.readLine())!=null)
{
responseBuffer.append(line);
}
return responseBuffer.toString();
}
catch(Exception ex){
Log.e(getClass().getName(), ex.getMessage(),ex);
return null;
}
}
public boolean is_connected(){
ConnectivityManager conMgr = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo i = conMgr.getActiveNetworkInfo();
if (i == null)
return false;
if (!i.isConnected())
return false;
if (!i.isAvailable())
return false;
return true;
}
private void loading(){
lDialog = new ProgressDialog(this);
lDialog.setMessage("Loading...");
lDialog.setCancelable(false);
lDialog.show();
}
/*** Location ***/
@Override
public void onLocationChanged(Location arg0) {
// TODO Auto-generated method stub
int lat = (int) (arg0.getLatitude());
int lng = (int) (arg0.getLongitude());
lattitude = "Lattitude: "+ lat ;
longitude = "Longitude: "+ lng;
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
////TODO Auto-generated method stub
}
}
班级：
SuperAdapter
package com.example.shop;
import java.util.ArrayList;
import com.example.shop.Super;
import com.example.shop.R;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
public class SuperAdapter extends BaseAdapter {
public ArrayList<Super> getItems_producte() {
return items_producte;
}
private Activity activity;
private ArrayList<Super> items_producte;
public SuperAdapter(Activity activity, ArrayList<Super> items_producte){
this.activity = activity;
this.items_producte= items_producte;
}
@Override
public int getCount() {
if(items_producte==null){
return 0;
}
else{
return items_producte.size();
} }
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return items_producte.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View contentView, ViewGroup Parent) {
// TODO Auto-generated method stub
View view = contentView;
if(view==null){
LayoutInflater inflate =(LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflate.inflate(R.layout.info_product, null,false);
}
Super item_producto = items_producte.get(position);
TextView id = (TextView)view.findViewById(R.id.list_product_id);
TextView fabricant = (TextView)view.findViewById(R.id.list_product_fabricant);
TextView nom = (TextView)view.findViewById(R.id.list_product_nom);
TextView preu = (TextView)view.findViewById(R.id.list_product_preu);
TextView stock = (TextView)view.findViewById(R.id.list_product_stock);
id.setText(Integer.toString(item_producto.getId()));
fabricant.setText(item_producto.getFabricant());
nom.setText(item_producto.getNom());
preu.setText(Float.toString(item_producto.getPreu()));
stock.setText(Integer.toString(item_producto.getStock()));
fabricant.setTextColor(activity.getResources().getColor(R.color.fabricant));
nom.setTextColor(activity.getResources().getColor(R.color.fabricant));
preu.setTextColor(activity.getResources().getColor(R.color.fabricant));
stock.setTextColor(activity.getResources().getColor(R.color.fabricant));
if(position%2==0){
view.setBackgroundColor(activity.getResources().getColor(R.color.files_parelles));
}
else{
view.setBackgroundColor(activity.getResources().getColor(R.color.files_imparelles));
}
/*STOKE COLOR*/
if(item_producto.getStock()<=0){
view.setBackgroundColor(activity.getResources().getColor(R.color.stock_null_bg));
fabricant.setTextColor(activity.getResources().getColor(R.color.stock_null_tx));
nom.setTextColor(activity.getResources().getColor(R.color.stock_null_tx));
preu.setTextColor(activity.getResources().getColor(R.color.stock_null_tx));
stock.setTextColor(activity.getResources().getColor(R.color.stock_null_tx));
}
return view;
}
public void setItems_producto(ArrayList<Super> items_producto) {
this.items_producte = items_producto;
this.notifyDataSetChanged();
}
}
**LongAsyncTask**
package com.example.shop;
import android.os.AsyncTask;
public class LongAsyncTask extends AsyncTask<String,String,String>{
@Override
protected String doInBackground(String... arg0) {
return null;
}
protected void onPostExecute(String result) {
}
}
Store.java
package com.example.shop;
import java.util.ArrayList;
import com.google.gson.Gson;
public class Store {
private String store;
private ArrayList<Super> productes;
public String getStore() {
return store;
}
public void setSupermercado(String store) {
this.store = store;
}
public ArrayList<Super> getProductos() {
return productes;
}
public void setProductes(ArrayList<Super> productes) {
this.productes = productes;
}
static Store newStore(String json_string){
Gson gson= new Gson();
Store store = gson.fromJson(json_string,Store.class);
return store;
}
}
Super.java
package com.example.shop;
public class Super {
private int id;
private String fabricant;
private String nom;
private float preu;
private int stock;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFabricant() {
return fabricant;
}
public void setFabricant(String fabricant) {
this.fabricant = fabricant;
}
public String getNom() {
return nom;
}
public void setNom(String nom) {
this.nom = nom;
}
public float getPreu() {
return preu;
}
public void setPreu(float preu) {
this.preu = preu;
}
public int getStock() {
return stock;
}
public void setStock(int stock) {
this.stock = stock;
}
}
LongAsyncTask.java
package com.example.shop;
import android.os.AsyncTask;
public class LongAsyncTask extends AsyncTask<String,String,String>{
@Override
protected String doInBackground(String... arg0) {
return null;
}
protected void onPostExecute(String result) {
}
}
有人能帮助我理解错误是什么吗？我建立了这个应用程序基于一个非常相似的应用程序，它确实工作，但当它试图在屏幕上打印列表时我的崩溃。
我也检查了所有类，我没有看到从一个到另一个的函数调用有任何问题，这样：我真的被困在这个。
非常感谢你。
答案 0 :(得分：2)
根据Logcat您获得了NullPointerException：
com.example.shop.Tenda.refreshListByJson(Tenda.java:305)
在这一行：
Log.i("store-nom", store.getStore());//line 305
这意味着store.getStore()会返回null。您必须向null提供非String Log。
您可以尝试这样打印：
Log.i("store-nom", "" + store.getStore());
或者只是确保store.getStore()不是null。