【发布时间】：2016-05-25 06:47:31
【问题描述】：
我正在尝试编写一个代码，该代码在应用程序加载时将地图缩放到当前位置。
这是我用来缩放地图的代码。
//Zoom to the current location
public Location getMyLocation() {
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null)
{
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(location.getLatitude(), location.getLongitude())) // Sets the center of the map to location user
.zoom(17) // 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));
}
return location;
}
然后我调用了Fragment的onCreateView里面的方法。
这是代码。
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if(!isGooglePlayServiceAvailable())
{
return null;
}
if(rootView != null)
{
ViewGroup parent = (ViewGroup)rootView.getParent();
if(parent != null)
{
parent.removeView(rootView);
}
}
else
{
rootView = inflater.inflate(R.layout.google_maps, container, false);
map = ((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map))
.getMap();
map.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker").snippet("Snippet"));
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, false);
if(bestProvider != null)
{
Location location = locationManager.getLastKnownLocation(bestProvider);
if(location != null)
{
onLocationChanged(location);
}
locationManager.requestLocationUpdates(bestProvider, 20000, 0, this);
}
}
return rootView;
}
但是，我的代码似乎没有执行这个缩放部分。
我对 Android 有点陌生，这是我在片段中使用的第一个代码（我之所以这么说是因为这对于高级人员来说可能是一个低级问题）。那么，有人可以告诉我有什么具体的方法来实现片段吗？
提前致谢。 :)
-编辑-
这是我的GoogleMapsFragment.java
public class GoogleMapsFragment extends android.support.v4.app.Fragment implements LocationListener {
View rootView;
static final LatLng HAMBURG = new LatLng(53.558, 9.927);
private GoogleMap map;
public GoogleMapsFragment()
{
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if(!isGooglePlayServiceAvailable())
{
return null;
}
if(rootView != null)
{
ViewGroup parent = (ViewGroup)rootView.getParent();
if(parent != null)
{
parent.removeView(rootView);
}
}
else
{
rootView = inflater.inflate(R.layout.google_maps, container, false);
map = ((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map))
.getMap();
map.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker").snippet("Snippet"));
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, false);
if(bestProvider != null)
{
Location location = locationManager.getLastKnownLocation(bestProvider);
if(location != null)
{
onLocationChanged(location);
}
locationManager.requestLocationUpdates(bestProvider, 20000, 0, this);
}
}
return rootView;
}
//Zoom to the current location
public Location getMyLocation() {
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null)
{
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(location.getLatitude(), location.getLongitude())) // Sets the center of the map to location user
.zoom(17) // 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));
}
return location;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
map.setMyLocationEnabled(true); // Identify the current location of the device
Location currentLocation = getMyLocation(); // Calling the getMyLocation method
}
@Override
public void onLocationChanged(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
LatLng latLng = new LatLng(latitude, longitude);
map.addMarker(new MarkerOptions().position(latLng));
map.moveCamera(CameraUpdateFactory.newLatLng(latLng));
map.animateCamera(CameraUpdateFactory.zoomTo(15));
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
private boolean isGooglePlayServiceAvailable()
{
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity());
if(ConnectionResult.SUCCESS == status)
{
return true;
}
else
{
GooglePlayServicesUtil.getErrorDialog(status, getActivity(), 0).show();
return false;
}
}
}
【问题讨论】：
-
在返回视图之前，您正在调用缩放部分。因此，您将永远看不到它。只需将缩放代码的 animateCamera 移动到 onActivityCreated，或在 Resume 上或在 onCreateView 之后的任何方法中
-
我添加了我的整个片段。你能更具体吗？有点新的Android。所以，不知道某些方法是如何工作的。 :( 谢谢 :)
-
在您的类中添加一个名为 onActivityCreated 的新方法。如果您使用的是 Android Studio，请单击类中的任意位置而不是内部方法，然后按 ALT + 插入键 > 覆盖方法。这将向您显示所有可用的覆盖方法的列表。然后选择onActivityCreated。然后移动你的 map.setMyLocationEnabled(true);和位置 currentLocation = getMyLocation();线到这个方法。另外，请务必检查地图的空指针。
-
在深入检查您的代码之前，我发现您正在使用
getMap()，它已被弃用。您是否正在遵循特定的教程？我建议先研究最新的实现（quickstart here）。在那里你可以看到不同之处，并建议使用像getMapAsync()这样的方法。另外，在快速启动运行后，您可以继续按照您想要的方式修改代码。干杯! :) -
嗨 Yasir Tahir，按照您在此处所说的做了。请参阅我编辑的答案。仍然没有运气:(
标签： android google-maps android-fragments