我有一个包含地点及其坐标的数据库。我想创建片段，我将在其中列出对我来说超过 5 公里的地方列表。我的代码是：
我从下一个开始片段：
case R.id.btn_near:
if(isOnline()){
ft = getSupportFragmentManager().beginTransaction().replace(
R.id.content_frame, frg);
ft.commit();
}
else
Toast.makeText(this, "Подключите интернет", 1000).show();
break;
FragmentNear.class
public class FragmentNear extends Fragment implements
android.location.LocationListener {
Cursor c;
View v;
ListView lvMore5;
Database db;
protected LocationManager locationManager;
String lat;
String provider;
protected String latitude, longitude;
protected boolean gps_enabled, network_enabled;
double myLat, myLong;
SimpleCursorAdapter scAdapter;
String[] from;
int[] to;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("myLogs", "-------- onCreateView " + myLat + " " + myLong);
v = inflater.inflate(R.layout.fragment_near, null);
lvMore5 = (ListView) v.findViewById(R.id.lv_more_5);
Log.d("myLogs", "-------- onCreateViewEnd " + myLat + " " + myLong);
return v;
}
@Override
public void onResume() {
db = new Database(getActivity());
db.open();
from = new String[] { Database.PLACE_NAME, Database.PLACE_DISTANCE,
Database.PLACE_ADRESS };
to = new int[] { R.id.tv_place_name_n, R.id.tv_distance,
R.id.tv_place_adress_n };
Log.d("myLogs", "-------- onCreate " + myLat + " " + myLong);
locationManager = (LocationManager) getActivity().getSystemService(
Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, 0, 0, this);
super.onResume();
}
public double getDistance(double myLat, double myLong, double pointLat,
double pointLong) {
Log.d("myLogs", "getDistance =" + myLat + " " + myLong);
double distance = 0;
Location locationA = new Location("A");
// 69.019207,33.085015",
locationA.setLatitude(myLat);
locationA.setLongitude(myLong);
Location locationB = new Location("B");
locationB.setLatitude(pointLat);
locationB.setLongitude(pointLong);
distance = locationA.distanceTo(locationB);
return distance / 1000;
}
@Override
public void onLocationChanged(Location location) {
final Location loc = location;
myLat = loc.getLatitude();
myLong = location.getLongitude();
Log.d("myLogs", "-------- onLoChangedEnd " + myLat + " " + myLong);
calculateDistance();---I want to calculate distance after i get my location
}
@Override
public void onStop() {
db.close();
if (c != null) {
c.close();
}
super.onStop();
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
public void calculateDistance() {
c = db.getPlaceByGroup(3);
if (c != null) {
if (c.moveToFirst()) {
do {
String s = c.getString(8);
double lat, lon;
lat = Double.valueOf(s.substring(0, s.indexOf(",")));
lon = Double.valueOf(s.substring(s.indexOf(",") + 1,
s.length()));
Log.d("myLogs",
"id= " + c.getInt(0) + "Coordinates"
+ c.getString(8));// !!
ContentValues cv = new ContentValues();
cv.put(Database.PLACE_DISTANCE,
getDistance(myLat, myLong, lat, lon));
int updCount = db.mDB.update(Database.DB_TABLE_PLACES, cv,
"_id = " + db.getPlaceId(3, c.getPosition()), null);
Log.d("myLogs", "updated rows count = " + updCount);
} while (c.moveToNext());
// Log.d("myLogs","N1ame =" +c.getString(1));
}
} else
Log.d("myLogs", "Cursor is null");
c = db.getPlacesMore5000();
scAdapter = new SimpleCursorAdapter(getActivity(),
R.layout.item_near_list, c, from, to);
lvMore5.setCacheColorHint(Color.TRANSPARENT);
lvMore5.setAdapter(scAdapter);
lvMore5.setOnTouchListener(new ListView.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
// Disallow ScrollView to intercept touch events.
v.getParent().requestDisallowInterceptTouchEvent(true);
break;
case MotionEvent.ACTION_UP:
// Allow ScrollView to intercept touch events.
v.getParent().requestDisallowInterceptTouchEvent(false);
break;
}
// Handle ListView touch events.
v.onTouchEvent(event);
return true;
}
});
lvMore5.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Fragment fragment = new FragmentPlaceInfo();
db.open();
Bundle data = new Bundle();
c = db.getPlacesMore5000();
if (c != null) {
c.moveToPosition(position);
data.putInt("placeId", c.getInt(0));
} else
Log.d("myLogs", "Cursor is null");
fragment.setArguments(data);
FragmentTransaction transaction = getFragmentManager()
.beginTransaction();
transaction.replace(R.id.content_frame, fragment);
transaction.addToBackStack(null);
transaction.commit();
// /less 1
}
});
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
真实设备 - wgen 我按下 R.id.btn_near - 一切都很好，当我再次按下它时（我想再次运行片段） - 我得到错误
08-23 17:52:39.928: E/AndroidRuntime(2953): FATAL EXCEPTION: main
08-23 17:52:39.928: E/AndroidRuntime(2953): java.lang.NullPointerException
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.support.v4.widget.ResourceCursorAdapter.<init>(ResourceCursorAdapter.java:56)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.support.v4.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:63)
08-23 17:52:39.928: E/AndroidRuntime(2953): at com.example.cars51ru.FragmentNear.showMFD(FragmentNear.java:352)
08-23 17:52:39.928: E/AndroidRuntime(2953): at com.example.cars51ru.FragmentNear.onLocationChanged(FragmentNear.java:124)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:227)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:160)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:176)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.os.Handler.dispatchMessage(Handler.java:99)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.os.Looper.loop(Looper.java:123)
08-23 17:52:39.928: E/AndroidRuntime(2953): at android.app.ActivityThread.main(ActivityThread.java:3839)
08-23 17:52:39.928: E/AndroidRuntime(2953): at java.lang.reflect.Method.invokeNative(Native Method)
08-23 17:52:39.928: E/AndroidRuntime(2953): at java.lang.reflect.Method.invoke(Method.java:507)
08-23 17:52:39.928: E/AndroidRuntime(2953): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
08-23 17:52:39.928: E/AndroidRuntime(2953): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
08-23 17:52:39.928: E/AndroidRuntime(2953): at dalvik.system.NativeStart.main(Native Method)
在这一行：scAdapter = new SimpleCursorAdapter(getActivity(),
R.layout.item_near_list, c, from, to);
当我在模拟器上启动它时 - 我得到空的 listView。