问题
i have read in the premium user guide that we can download a small amount of map with MapDataPrefetcher. i use a Mapfragment to show the map in my app, and it says that the MapEngine is automatically initialized by using MapFragment.
the problem is that i can't understand how to apply the methods and where i need to initialize the request for downloading the bounding box itself. its not so clear in the user guide.
if someone here can help me with that problem or send an example of the implementation i will be very grateful!
this is my init method for the map and the map fragment
private void initialize() {
setContentView(R.layout.activity_main);
// Search for the map fragment to finish setup by calling init().
// mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.mapfragment);
mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.mapfragment);
mLocationInfo = (TextView) findViewById(R.id.textViewLocationInfo);
mapFragment.setRetainInstance(false);
// Set up disk cache path for the map service for this application
// It is recommended to use a path under your application folder for storing the disk cache
boolean success = com.here.android.mpa.common.MapSettings.setIsolatedDiskCacheRootPath(
getApplicationContext().getExternalFilesDir(null)+File.separator + ".here-maps",
"com.example.andrey88.MapService"); /* ATTENTION! Do not forget to update {YOUR_INTENT_NAME} */
if (!success) {
Toast.makeText(getApplicationContext(), "Unable to set isolated disk cache path.", Toast.LENGTH_LONG);
} else {
mapFragment.init(new OnEngineInitListener() {
@Override
public void onEngineInitializationCompleted(OnEngineInitListener.Error error) {
if (error == OnEngineInitListener.Error.NONE) {
// retrieve a reference of the map from the map fragment
map = mapFragment.getMap();
// Set the map center to the Ruppin region (no animation)
map.setCenter(new GeoCoordinate(32.343099, 34.911272, 0.0), Map.Animation.NONE);
// Set the zoom level
map.setZoomLevel(17.8);
map.setMapScheme(Map.Scheme.PEDESTRIAN_DAY);
map.setLandmarksVisible(false);
map.setProjectionMode(Map.Projection.MERCATOR);
map.getPedestrianFeaturesVisible();
// position of user
map.addTransformListener(MainActivity.this);
mPositioningManager = PositioningManager.getInstance();
// check source of getting geo location
mHereLocation = LocationDataSourceHERE.getInstance(
new StatusListener() {
@Override
public void onOfflineModeChanged(boolean offline) {
// called when offline mode changes
}
@Override
public void onAirplaneModeEnabled() {
// called when airplane mode is enabled
}
@Override
public void onWifiScansDisabled() {
// called when Wi-Fi scans are disabled
}
@Override
public void onBluetoothDisabled() {
// called when Bluetooth is disabled
}
@Override
public void onCellDisabled() {
// called when Cell radios are switch off
}
@Override
public void onGnssLocationDisabled() {
// called when GPS positioning is disabled
}
@Override
public void onNetworkLocationDisabled() {
// called when network positioning is disabled
}
@Override
public void onServiceError(StatusListener.ServiceError serviceError) {
// called on HERE service error
}
@Override
public void onPositioningError(PositioningError positioningError) {
// called when positioning fails
}
@Override
public void onWifiIndoorPositioningNotAvailable() {
// called when running on Android 9.0 (Pie) or newer
}
});
if (mHereLocation == null) {
Toast.makeText(MainActivity.this, "LocationDataSourceHERE.getInstance(): failed, exiting", Toast.LENGTH_LONG).show();
finish();
}
mPositioningManager.setDataSource(mHereLocation);
mPositioningManager.addListener(new WeakReference<PositioningManager.OnPositionChangedListener>(MainActivity.this));
// Create a custom marker image
com.here.android.mpa.common.Image myImage = new com.here.android.mpa.common.Image();
try {myImage.setImageResource(R.drawable.marker_round);
} catch (IOException e) {
finish();
}
initMarkers(myImage);
createPolygon();
mapFragment.getMapGesture().addOnGestureListener(new MapGesture.OnGestureListener() {
@Override
public void onPanStart() {
}
@Override
public void onPanEnd() {
}
@Override
public void onMultiFingerManipulationStart() {
}
@Override
public void onMultiFingerManipulationEnd() {
}
@Override
public boolean onMapObjectsSelected(List<ViewObject> list) {
return false;
}
@Override
public boolean onTapEvent(PointF pointF) {
return false;
}
@Override
public boolean onDoubleTapEvent(PointF pointF) {
return false;
}
@Override
public void onPinchLocked() {
}
@Override
public boolean onPinchZoomEvent(float v, PointF pointF) {
return false;
}
@Override
public void onRotateLocked() {
}
@Override
public boolean onRotateEvent(float v) {
return false;
}
@Override
public boolean onTiltEvent(float v) {
return false;
}
@Override
public boolean onLongPressEvent(PointF pointF) {
return false;
}
@Override
public void onLongPressRelease() {
}
@Override
public boolean onTwoFingerTapEvent(PointF pointF) {
return false;
}
}, 0, false);
if (mPositioningManager.start(PositioningManager.LocationMethod.GPS_NETWORK_INDOOR)) {
mapFragment.getPositionIndicator().setVisible(true);
} else {
Toast.makeText(MainActivity.this, "PositioningManager.start: failed, exiting", Toast.LENGTH_LONG).show();
finish();
}
}
else {
Log.d("errorTag",error.name());
onDestroy();
}
}
});
}
}
回答1:
MapEngine must be initialized before it can be used. It should be done in the main thread. MapEngine is automatically initialized for your application by using AndroidXMapFragment. AndroidXMapFragment is a fragment class applications can use as a UI module in an activity for map display. However, if your application does not use AndroidXMapFragment classes, then the application should initialize the MapEngine directly before using any HERE APIs. You can do this by calling MapEngine.init(ApplicationContext, OnEngineInitListener) as shown below:
MapEngine mapEngine = MapEngine.getInstance(); ApplicationContext appContext = new ApplicationContext(context); mapEngine.init(appContext, new OnEngineInitListener() { @Override public void onEngineInitializationCompleted(Error error) {
if (error == OnEngineInitListener.Error.NONE) {
// Post initialization code goes here
} else {
// handle factory initialization failure
} } });
来源：https://stackoverflow.com/questions/53691830/map-download-by-specifying-a-bounding-box-implementation