Attualmente sto scrivendo un'app che mostra un MapView che mostra una mappa di google. ho usato il tutorial "ciao mappa" dal http://developer.android.com/resources/tutorials/views/hello-mapview.html e questo funziona fino ad ora: la mappa viene visualizzata, centrata e ingrandita correttamente, anche gli oggetti sovrapposti aggiunti sono visualizzati correttamente.GoogleMaps MapView si arresta su Tap in Android?
ma quando clicco su uno di quegli elementi di sovrapposizione ho aggiunto, l'applicazione va in crash con un'eccezione di puntatore nullo:
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): java.lang.NullPointerException
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.app.AlertController$AlertParams.<init>(AlertController.java:753)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:273)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at net.xenonite.wifiloc.act_map$MapItemizedOverlay.onTap(act_map.java:182)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.google.android.maps.ItemizedOverlay.onTap(ItemizedOverlay.java:453)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.google.android.maps.OverlayBundle.onTap(OverlayBundle.java:83)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.google.android.maps.MapView$1.onSingleTapUp(MapView.java:347)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.google.android.maps.GestureDetector.onTouchEvent(GestureDetector.java:533)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.google.android.maps.MapView.onTouchEvent(MapView.java:647)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.View.dispatchTouchEvent(View.java:3709)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:874)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:924)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1695)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1116)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.app.Activity.dispatchTouchEvent(Activity.java:2068)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1679)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.view.ViewRoot.handleMessage(ViewRoot.java:1708)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.os.Handler.dispatchMessage(Handler.java:99)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.os.Looper.loop(Looper.java:123)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at android.app.ActivityThread.main(ActivityThread.java:4595)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at java.lang.reflect.Method.invokeNative(Native Method)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at java.lang.reflect.Method.invoke(Method.java:521)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
07-23 16:24:48.167: ERROR/AndroidRuntime(2530): at dalvik.system.NativeStart.main(Native Method)
il mio codice è in gran parte copiato dal tutorial:
public class act_map extends MapActivity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
intent = getIntent();
lat = intent.getDoubleExtra("lat", 0.0);
lng = intent.getDoubleExtra("lng", 0.0);
MapView = (MapView) findViewById(R.id.act_map_mapview);
List<Overlay> mapOverlays = MapView.getOverlays();
Drawable positionMarker
= getResources().getDrawable(R.drawable.act_map_androidmarker);
MapItemizedOverlay itemizedOverlay
= new MapItemizedOverlay(positionMarker);
geoPoint = new GeoPoint((int) (lat * 1000000), (int) (lng * 1000000));
Pointer = new OverlayItem(geoPoint, "Thats me!", "wohooo");
itemizedOverlay.addOverlay(Pointer);
mapOverlays.add(itemizedOverlay);
MapView.setSatellite(false);
MapController = MapView.getController();
MapController.setCenter(geoPoint);
MapController.setZoom(18);
MapView.setBuiltInZoomControls(true);
MapView.displayZoomControls(true);
}
@Override
protected boolean isRouteDisplayed()
{
return false;
}
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (keyCode == KeyEvent.KEYCODE_I)
{
MapView.getController().setZoom(MapView.getZoomLevel() + 1);
return true;
}
else if (keyCode == KeyEvent.KEYCODE_O)
{
MapView.getController().setZoom(MapView.getZoomLevel() - 1);
return true;
}
else if (keyCode == KeyEvent.KEYCODE_S)
{
MapView.setSatellite(true);
return true;
}
else if (keyCode == KeyEvent.KEYCODE_M)
{
MapView.setSatellite(false);
return true;
}
return false;
}
public class MapItemizedOverlay extends ItemizedOverlay<OverlayItem>
{
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
private Context mContext;
public MapItemizedOverlay(Drawable defaultMarker)
{
super(boundCenterBottom(defaultMarker));
}
public MapItemizedOverlay(Drawable defaultMarker, Context context)
{
super(defaultMarker);
mContext = context;
}
public void addOverlay(OverlayItem overlay)
{
mOverlays.add(overlay);
populate();
}
@Override
protected OverlayItem createItem(int i)
{
return mOverlays.get(i);
}
@Override
public int size()
{
return mOverlays.size();
}
@Override
protected boolean onTap(int index)
{
OverlayItem item = mOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}
}
Come devo risolvere questo?
grazie! questo ha risolto il problema! – xenonite
E se non fosse in una classe interiore? –