我正在尝试在GMaps中设置自定义标记，我为其创建了自定义布局。我在我的地图活动中对我的自定义布局进行了膨胀，然后将其转换为位图，然后将相同的位图传递给BitmapDescriptorFactory.fromBitmap(bitmap)，但我得到java.lang.NullPointerException: null reference这是我的地图活动
public class GPSLocation extends FragmentActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, OnMapReadyCallback {
LatLng latLng = null;
GoogleApiClient googleApiClient;
GoogleMap map;
int animation = 0;
TextView marker;
View v;
Bitmap mainBitmap;
LayoutInflater inflater;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
inflater = getLayoutInflater();
setContentView(R.layout.activity_gpslocation);
v = inflater.inflate(R.layout.marker,null);
marker = (TextView) v.findViewById(R.id.marker);
mainBitmap = ConvertToBitmap(v);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
checkGps();
getCurrentLocation();
}
protected Bitmap ConvertToBitmap(View v) {
Bitmap map2;
Log.v("BitmapObject", "Inside");
v.setDrawingCacheEnabled(true);
v.buildDrawingCache();
return map2 = v.getDrawingCache();
}
@Override
public void onConnected(@Nullable Bundle bundle) {
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
@Override
public void onMapReady(GoogleMap googleMap) {
map = googleMap;
}
//Gets Current Location
private LatLng getCurrentLocation() {
new SamLocationRequestService(GPSLocation.this).executeService(new SamLocationRequestService.SamLocationListener() {
@Override
public void onLocationUpdate(Location location, Address address) {
latLng = new LatLng(location.getLatitude(), location.getLongitude());
drawMarker(latLng, mainBitmap, "My Location");
getPlaces(location.getLatitude() + "", location.getLongitude() + "", "500", "atm");
Toast.makeText(GPSLocation.this, location.getLatitude() + "," + location.getLongitude() + "", Toast.LENGTH_SHORT).show();
}
});
return latLng;
}
//Check GPS is turned On or not
private void checkGps() {
if (googleApiClient == null) {
googleApiClient = new GoogleApiClient.Builder(GPSLocation.this)
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this).build();
googleApiClient.connect();
LocationRequest locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(30 * 1000);
locationRequest.setFastestInterval(5 * 1000);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder().addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
PendingResult<LocationSettingsResult> result = LocationServices.SettingsApi.checkLocationSettings(googleApiClient, builder.build());
result.setResultCallback(new ResultCallback<LocationSettingsResult>() {
@Override
public void onResult(LocationSettingsResult result) {
final Status status = result.getStatus();
final LocationSettingsStates state = result.getLocationSettingsStates();
switch (status.getStatusCode()) {
case LocationSettingsStatusCodes.SUCCESS:
getCurrentLocation();
googleApiClient = null;
// All location settings are satisfied. The client can initialize location
// requests here.
break;
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
// Location settings are not satisfied. But could be fixed by showing the user
// a dialog.
try {
// Show the dialog by calling startResolutionForResult(),
// and check the result in onActivityResult().
status.startResolutionForResult(GPSLocation.this, 1000);
} catch (IntentSender.SendIntentException e) {
// Ignore the error.
}
googleApiClient = null;
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
// Location settings are not satisfied. However, we have no way to fix the
// settings so we won't show the dialog.
googleApiClient = null;
break;
}
}
});
}
}
//End
public void drawMarker(LatLng latLng, Bitmap bitmap, String name) {
if (animation == 0) {
map.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(latLng) // Sets the center of the map to location user
.zoom(15) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(40) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
map.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
animation = 1;
}
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title(name);
markerOptions.icon(BitmapDescriptorFactory.fromBitmap(bitmap));
map.addMarker(markerOptions);
}
void getPlaces(String lat, String lon, String radious, String type) {
StringBuilder sb = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
sb.append("location=" + lat + "," + lon);
sb.append("&radius=" + radious);
sb.append("&types=" + type);
sb.append("&sensor=true");
sb.append("&key=MyAPIKey");
AndroidNetworking.initialize(GPSLocation.this);
AndroidNetworking.get(sb.toString())
//.addJSONObjectBody(object)
.setTag("Token")
.setPriority(Priority.MEDIUM)
.build()
.getAsJSONObject(new JSONObjectRequestListener() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray array = response.getJSONArray("results");
for (int i = 0; i < array.length(); i++) {
JSONObject object = array.getJSONObject(i);
String latitude = object.getJSONObject("geometry").getJSONObject("location").getString("lat");
String longitude = object.getJSONObject("geometry").getJSONObject("location").getString("lng");
String name = object.getString("name");
String vicinity = object.getString("vicinity");
String reference = object.getString("reference");
LatLng latLng = new LatLng(Double.parseDouble(latitude), Double.parseDouble(longitude));
marker.setText(name.toString());
//drawMarker(latLng, mainBitmap, name + "\n" + vicinity);
}
//drawMarker(CurrentPos, "My Location", "0", BitmapDescriptorFactory.HUE_BLUE);
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onError(ANError anError) {
}
});
}
}
我在自己的Java文件（marker.xml）中膨胀的自定义标记布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/llm"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="30dp"
android:layout_height="30dp"
android:background="@drawable/google_selector"
android:gravity="center"
android:padding="2dp"
android:text="ATM"
android:textColor="#FFFFFF"
android:textSize="9dp"
android:textStyle="bold" />
<TextView
android:id="@+id/marker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="4dp"
android:text="Axis"
android:textColor="#000000"
android:textSize="9dp" />
</LinearLayout>
我的错误日志：
12-25 19:22:27.330 32741-32741/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.aamir.myapplication, PID: 32741
java.lang.NullPointerException: null reference
at maps.w.d.a(Unknown Source)
at maps.ad.f$a.<init>(Unknown Source)
at maps.ad.f.a(Unknown Source)
at maps.ad.S.<init>(Unknown Source)
at maps.ad.t.a(Unknown Source)
at xj.onTransact(:com.google.android.gms.DynamiteModulesB:167)
at android.os.Binder.transact(Binder.java:392)
at com.google.android.gms.maps.internal.IGoogleMapDelegate$zza$zza.addMarker(Unknown Source)
at com.google.android.gms.maps.GoogleMap.addMarker(Unknown Source)
at com.example.aamir.myapplication.GPSLocation.drawMarker(GPSLocation.java:190)
at com.example.aamir.myapplication.GPSLocation$1.onLocationUpdate(GPSLocation.java:109)
at com.entire.sammalik.samlocationandgeocoding.SamLocationRequestService.onLocationChanged(SamLocationRequestService.java:101)
at com.google.android.gms.location.internal.zzk$zzb.handleMessage(Unknown Source)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:5776)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)
P.S：我正在使用Android网络库进行网络操作。
答案 0 :(得分：1)
我猜Null Pointer Exception是因为当您在drawMarker方法中调用getCurrentLocation()方法时地图尚未准备就绪。
在准备好使用地图时尝试从getCurrentLocation()方法调用onMapReady方法，并在getCurrentLocation()方法中删除onCreate方法调用。
答案 1 :(得分：0)
我使用了this教程中的位图转换方法，但它确实有效。可能是我在将布局转换为位图时做错了...感谢所有人的帮助..