我有一个 java.lang.NullPointerException。
我找不到问题。
记录在下面。
public class GPSActivity extends MapActivity {
Location location;
EditText editTextLat, editTexLng, editTextAddress;
// overlay
Geocoder coder;
MapView mapview;
MapController controller;
MyItemizedOverlay itemizedOverlay;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gps_layout);
mapview = (MapView) findViewById(R.id.mapview);
controller = mapview.getController();
controller.setZoom(16);
MapOverlay mapOverlay = new MapOverlay();
List<Overlay> listOfOverlays = mapview.getOverlays();
listOfOverlays.add(mapOverlay);
Drawable drawable = getResources().getDrawable(R.drawable.ic_launcher);
itemizedOverlay = new MyItemizedOverlay(drawable);
listOfOverlays.add(itemizedOverlay);
coder = new Geocoder(this, Locale.KOREA);
editTextLat = (EditText) findViewById(R.id.editText1);
editTexLng = (EditText) findViewById(R.id.editText2);
editTextAddress = (EditText) findViewById(R.id.editText3);
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.NO_REQUIREMENT);
criteria.setPowerRequirement(Criteria.NO_REQUIREMENT);
String provider = locationManager.getBestProvider(criteria, true);
location = locationManager.getLastKnownLocation(provider);
updateLocation(location.getLatitude(), location.getLongitude());
locationManager.requestLocationUpdates(provider, 2000, 10,
mLocationListener); }
private void updateLocation(double lat, double lng) {
String sLocationInfo = "";
if (location != null) {
editTextLat.setText(String.valueOf(lat));
editTexLng.setText(String.valueOf(lng));
GeoPoint point = new GeoPoint((int) (lat * 1E6), (int) (lng * 1e6));
controller.animateTo(point);
OverlayItem overlayItem = new OverlayItem(point, null, null);
itemizedOverlay.addOverlay(overlayItem); try {
List<Address> addresses = coder.getFromLocation(lat, lng, 1);
if (addresses != null) {
Address addr = addresses.get(0);
for (int i = 0; i <= addr.getMaxAddressLineIndex(); i++) {
String addLine = addr.getAddressLine(i);
sLocationInfo += String.format("%s", addLine);
}
}
} catch (IOException e) {
Toast.makeText(getBaseContext(), "not found", Toast.LENGTH_SHORT).show();
}
location.setLatitude(lat);
location.setLongitude(lng);
} else {
sLocationInfo = "cant found location";
}
editTextAddress.setText(sLocationInfo);
}
LocationListener mLocationListener = new LocationListener() {
public void onLocationChanged(Location location) { // TODO
// Auto-generated
// method stub
updateLocation(location.getLatitude(), location.getLongitude());
}
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String provider) { // TODO Auto-generated
// method stub
}
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
};
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
class MapOverlay extends Overlay {
@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
// TODO Auto-generated method stub
if (e.getAction() == 1) {
GeoPoint point = mapView.getProjection().fromPixels(
(int) e.getX(), (int) e.getY());
updateLocation(point.getLatitudeE6() / 1E6,
point.getLongitudeE6() / 1E6);
}
return false;
}
}
class MyItemizedOverlay extends ItemizedOverlay<OverlayItem> {
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
public MyItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
// TODO Auto-generated constructor stub
}
@Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return mOverlays.get(i);
}
@Override
public int size() {
// TODO Auto-generated method stub
return mOverlays.size();
}
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}
}
}
这是日志。
criteria.setAccuracy(Criteria.NO_REQUIREMENT);
此行会产生运行时异常。
删除此行后，
我在'updateLocation(location.getLatitude(), location.getLongitude());处也遇到了运行时异常
“
我该如何解决？！
08-12 11:21:34.760: E/AndroidRuntime(2120): FATAL EXCEPTION: main
08-12 11:21:34.760: E/AndroidRuntime(2120): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lg.icou/com.lg.icou.GPSActivity}: java.lang.NullPointerException
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.os.Handler.dispatchMessage(Handler.java:99)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.os.Looper.loop(Looper.java:137)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread.main(ActivityThread.java:5041)
08-12 11:21:34.760: E/AndroidRuntime(2120): at java.lang.reflect.Method.invokeNative(Native Method)
08-12 11:21:34.760: E/AndroidRuntime(2120): at java.lang.reflect.Method.invoke(Method.java:511)
08-12 11:21:34.760: E/AndroidRuntime(2120): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-12 11:21:34.760: E/AndroidRuntime(2120): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-12 11:21:34.760: E/AndroidRuntime(2120): at dalvik.system.NativeStart.main(Native Method)
08-12 11:21:34.760: E/AndroidRuntime(2120): Caused by: java.lang.NullPointerException
08-12 11:21:34.760: E/AndroidRuntime(2120): at com.lg.icou.GPSActivity.onCreate(GPSActivity.java:62)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.Activity.performCreate(Activity.java:5104)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
08-12 11:21:34.760: E/AndroidRuntime(2120): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
08-12 11:21:34.760: E/AndroidRuntime(2120): ... 11 more
答案 0 :(得分：1)
location = locationManager.getLastKnownLocation(provider);
返回实际结果。因此，nullpointerexception。
答案 1 :(得分：0)
如果问题不在于可能返回位置的事实，那么此错误通常指向您可能尝试访问具有有效ID的视图但实际上不在当前布局中的事实。也许尝试使用try / catch来找出导致问题的视图。
try {
editTextLat = (EditText) findViewById(R.id.editText1);
} catch (Exception e) {
Log.e("MyTag", "Error accessing view editText1", e);
}
答案 2 :(得分：0)
我认为你需要这一行：
locationManager.requestLocationUpdates(provider, 2000, 10,
mLocationListener);
：
location = locationManager.getLastKnownLocation(provider);
据我所知，除非LocationListener正在运作并找到您的位置，否则无法获取位置信息。