【发布时间】：2014-10-28 10:07:17
【问题描述】：
大家好，我有一个无法解决的棘手错误。我正在处理列表视图，当位置服务处于活动状态时，我希望如果打开位置，我会看时间去某个地方，而当位置服务关闭时，我会显示一条消息而不是时间。没什么特别的。但是我有一个棘手的错误，例如，如果我有 GPS，那么很好的位置，工作，如果我关闭所有位置，工作，但如果我有粗略的位置活动，应用程序崩溃......这真的很棘手。在我的代码和我的 logcat 下方。谢谢大家。
全类代码：
package com.example.findmyclients;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Element;
import android.app.Activity;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class ListviewActivity extends Activity{
private ListView lista;
private ListView listaNOGPS;
private List<InterestPoint> listaInteressPoint;
private List<InterestPoint> listaInteressPointNOGPS;
private InterestPoint ip;
private CustomListAdapter adapter;
private CustomListAdapter adapterNOGPS;
public String [][]ArrayTime = new String[1000][6]; //La matrice che conterrà tutti i dati relativi alla lista
public String [][]Dati_history = new String[100][10];
public String [][]Dati_restaurant = new String[100][10];
public String [][]Dati_hotel = new String[100][10];
public String [][]Dati_souvenir = new String[100][10];
public String pathdirectory = "/sdcard/PredappioLiving/";
String[]file_names={"markers_history.xml", "markers_hotel.xml", "markers_restaurant.xml", "markers_souvenir.xml"};
String[]Array_Cat={"Monumenti","Alloggi","Ristoranti","Negozi"};
int nome_luogo = 0;
int categoria = 1;
int auto = 2;
int piedi = 3;
int latitude = 4;
int longitude = 5;
int gps_on= 0;
@Override
protected void onCreate (Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
final Activity thiz = this;
//Get ListView Object from xml
lista = (ListView) thiz.findViewById(R.id.lista);
listaNOGPS = (ListView) thiz.findViewById(R.id.lista);
GPSTracker gpstrack = new GPSTracker(this);
if (gpstrack.canGetLocation() ) {
gps_on = 1;
}
/* - - - Costruzione della matrice dall'xml - - - */
/* - - - - - - - - - - - - - - - - - - - - - - - -*/
int file_choice=-1;
int n = 0; //mi serve per riempire bene tutta la matrice
for (int i = 0; i<file_names.length; i++)
{
String file_path = pathdirectory+file_names[i];
int indice_riempimento = n;
int returnhistory = file_names[i].compareTo("markers_history.xml");
int returnhotel = file_names[i].compareTo("markers_hotel.xml");
int returnrestaurant = file_names[i].compareTo("markers_restaurant.xml");
int returnsouvenir = file_names[i].compareTo("markers_souvenir.xml");
if (returnhistory == 0){
file_choice = 0;
}
if (returnhotel == 0){
file_choice = 1;
}
if (returnrestaurant == 0){
file_choice = 2;
}
if (returnsouvenir == 0){
file_choice = 3;
}
// Inizio lettura da XML e popolazione della matrice
try
{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(new FileInputStream(file_path));
doc.getDocumentElement().normalize();
NodeList nodi = doc.getElementsByTagName("marker");
for (int c = 0; c<nodi.getLength(); c++)
{
Element item = (Element) nodi.item(c);
String nome = item.getAttribute("name");
String destLat = item.getAttribute("lat");
String destLong = item.getAttribute("long");
Double lat = Double.valueOf(destLat);
Double lon = Double.valueOf(destLong);
GPSTracker gpsTracker = new GPSTracker(this);
String stringMyLatitude = String.valueOf(gpsTracker.latitude);
String stringMyLongitude = String.valueOf(gpsTracker.longitude);
double currentLat = Double.parseDouble(stringMyLatitude);
double currentLong = Double.parseDouble(stringMyLongitude);
final float[]distanzadouble = new float[3];
Location.distanceBetween(currentLat, currentLong, lat, lon, distanzadouble);
float metri = distanzadouble[0];
float km = Math.round((double)metri/1000);
int minuti_persona = (int)Math.round(metri/125); //125 metri al minuto -> velocità media di 2,5 m/s
int minuti_auto = (int)Math.round(km/0.7); //700 metri al minuto -> velocità media di 42 km/h
String string_min_a_piedi;
String string_min_in_auto;
if(minuti_persona <=0) // Stampa tempo per coprire la distanza
{
string_min_a_piedi="meno di un minuto";
}else
{
string_min_a_piedi=String.valueOf(minuti_persona);
}
if(minuti_auto <= 0)
{
string_min_in_auto="meno di un minuto";
}else
{
string_min_in_auto= String.valueOf(minuti_auto);
}
ArrayTime[c+n][nome_luogo] = nome;
ArrayTime[c+n][categoria] = Array_Cat[file_choice];
ArrayTime[c+n][auto] = string_min_in_auto;
ArrayTime[c+n][piedi] = string_min_a_piedi;
}
n = n+nodi.getLength();
}catch(Exception e)
{
e.printStackTrace();
}
}
//Arrays.sort(ArrayTime, new ColumnComparator(0));
//Stampa dell'array sulla lista - - -
/*
for(int i = 0; i<6; i++)
{
ip = new InterestPoint();
ip.nome = "pippo"+i;
ip.categoria ="cat pippo"+i;
ip.apiedi = "25";
ip.inauto = "10";
listaInteressPoint.add(ip);
}
*/
final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
if (gps_on == 1) {
listaInteressPoint = new ArrayList<InterestPoint>();
for(int i = 0; i<n;i++)
{
ip = new InterestPoint();
ip.nome = ArrayTime[i][nome_luogo];
ip.categoria = "Categoria: "+ArrayTime[i][categoria];
ip.inauto = "In auto: " +ArrayTime[i][auto]+ " minuti";
ip.apiedi = "A piedi: " +ArrayTime[i][piedi]+ " minuti";
listaInteressPoint.add(ip);
}
//Ordinamento
Collections.sort(listaInteressPoint, new Comparator<InterestPoint>(){
@Override
public int compare(InterestPoint elem1, InterestPoint elem2) {
return elem1.inauto.compareTo(elem2.inauto);
}
});
}else
{
listaInteressPointNOGPS = new ArrayList<InterestPoint>();
for(int i = 0; i<n;i++)
{
ip = new InterestPoint();
ip.nome = ArrayTime[i][nome_luogo];
ip.categoria = "Categoria: "+ArrayTime[i][categoria];
ip.inauto = "In auto: Attiva la posizione per la distanza";
ip.apiedi = "A piedi: in auto e a piedi";
listaInteressPointNOGPS.add(ip);
}
//Ordinamento
Collections.sort(listaInteressPointNOGPS, new Comparator<InterestPoint>(){
@Override
public int compare(InterestPoint elem1, InterestPoint elem2) {
return elem1.nome.compareTo(elem2.nome);
}
});
}
/*
//ListView Item Click Listener
listaNOGPS.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//ListView Clicked item index
int itemPosition = position;
InterestPoint item = adapter.getItem(position);
Intent piu_info = new Intent(thiz, MoreInfoActivity.class);
piu_info.putExtra("nome", item.nome);
startActivity(piu_info);
//ListView clicked item value
//int itemValue = (int) lista.getItemAtPosition(position);
//Show Alert
Toast.makeText(getApplicationContext(), "Position :"+itemPosition+" ListItem :"+ item.nome, Toast.LENGTH_LONG).show();
}
});
*/
//ListView Item Click Listener
lista.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if (gps_on == 1){
//ListView Clicked item index
int itemPosition = position;
InterestPoint item = adapter.getItem(position);
Intent piu_info = new Intent(thiz, MoreInfoActivity.class);
piu_info.putExtra("nome", item.nome);
startActivity(piu_info);
//ListView clicked item value
//int itemValue = (int) lista.getItemAtPosition(position);
//Show Alert
Toast.makeText(getApplicationContext(), "Position :"+itemPosition+" ListItem :"+ item.nome, Toast.LENGTH_LONG).show();
}else
{
//ListView Clicked item index
int itemPosition = position;
InterestPoint item = adapterNOGPS.getItem(position);
Intent piu_info = new Intent(thiz, MoreInfoActivity.class);
piu_info.putExtra("nome", item.nome);
startActivity(piu_info);
//ListView clicked item value
//int itemValue = (int) lista.getItemAtPosition(position);
//Show Alert
Toast.makeText(getApplicationContext(), "Position :"+itemPosition+" ListItem :"+ item.nome, Toast.LENGTH_LONG).show();
}
}
});
}
@Override
protected void onResume() {
super.onResume();
final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
adapter = new CustomListAdapter(getApplicationContext(), R.layout.list_item, listaInteressPoint);
adapterNOGPS = new CustomListAdapter(getApplicationContext(), R.layout.list_item, listaInteressPointNOGPS);
if (manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
lista.setAdapter(adapter);
}else
{
listaNOGPS.setAdapter(adapterNOGPS);
}
}
}
Logcat：
10-28 10:53:53.106: E/AndroidRuntime(445): FATAL EXCEPTION: main
10-28 10:53:53.106: E/AndroidRuntime(445): Process: com.example.findmyclients, PID: 445
10-28 10:53:53.106: E/AndroidRuntime(445): java.lang.RuntimeException: Unable to resume activity {com.example.findmyclients/com.example.findmyclients.ListviewActivity}: java.lang.NullPointerException
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3076)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3105)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.access$900(ActivityThread.java:175)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.os.Handler.dispatchMessage(Handler.java:102)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.os.Looper.loop(Looper.java:146)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.main(ActivityThread.java:5602)
10-28 10:53:53.106: E/AndroidRuntime(445): at java.lang.reflect.Method.invokeNative(Native Method)
10-28 10:53:53.106: E/AndroidRuntime(445): at java.lang.reflect.Method.invoke(Method.java:515)
10-28 10:53:53.106: E/AndroidRuntime(445): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
10-28 10:53:53.106: E/AndroidRuntime(445): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
10-28 10:53:53.106: E/AndroidRuntime(445): at dalvik.system.NativeStart.main(Native Method)
10-28 10:53:53.106: E/AndroidRuntime(445): Caused by: java.lang.NullPointerException
10-28 10:53:53.106: E/AndroidRuntime(445): at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:330)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.widget.ListView.setAdapter(ListView.java:486)
10-28 10:53:53.106: E/AndroidRuntime(445): at com.example.findmyclients.ListviewActivity.onResume(ListviewActivity.java:356)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1198)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.Activity.performResume(Activity.java:5530)
10-28 10:53:53.106: E/AndroidRuntime(445): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3066)
10-28 10:53:53.106: E/AndroidRuntime(445): ... 12 more
10-28 10:53:53.161: I/Process(445): Sending signal. PID: 445 SIG: 9
P.S.：粗略位置变量“gps_on”正确设置为“1”
【问题讨论】：
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请删除标题的“已解决”标签：meta.stackexchange.com/questions/116101/…。
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我还看到您编辑代码以将其发布更正。你不应该。有类似问题的人会来这里和你的编辑，没有人会明白答案在说什么。请阅读How to Ask 了解更多信息；）
标签： android listview android-listview location adapter