我需要你的帮助。
打开应用程序后，如何立即将相机移动到当前位置？
我有一个可以使用的按钮（如果单击它，它将使照相机移动到当前位置），但是当我打开该应用程序时，照相机被设置在大海的中央。 我想打开应用程序，并且相机已经设置在当前位置。
这是我的代码：
MapsActivity.java
import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesNotAvailableException;
import com.google.android.gms.common.GooglePlayServicesRepairableException;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.common.api.GoogleApi;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener, LocationListener {
private GoogleMap mMap;
private GoogleApiClient googleApiClient;
private LocationRequest locationRequest;
private Location lastLocation;
private Marker currentUserLocationMarker;
private static final int Request_User_Location_Code = 99;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
checkUserLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
/*disabling toolbar (it is used to continue using this app without having to
use the official google maps app)*/
mMap.getUiSettings().setMapToolbarEnabled(false);
}
public boolean checkUserLocationPermission(){
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){
if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)){
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, Request_User_Location_Code );
}
else{
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, Request_User_Location_Code );
}
return false;
}
else{
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case Request_User_Location_Code:
if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
if(googleApiClient == null){
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
}
else{
Toast.makeText(this, "Permesso vietato", Toast.LENGTH_SHORT).show();
}
return;
}
}
protected synchronized void buildGoogleApiClient(){
googleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
googleApiClient.connect();
}
@Override
public void onLocationChanged(Location location) {
lastLocation = location;
if(currentUserLocationMarker != null){
currentUserLocationMarker.remove();
}
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Posizione corrente");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE));
currentUserLocationMarker = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomBy(11));
if (googleApiClient != null){
LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient, this);
}
}
@Override
public void onConnected(@Nullable Bundle bundle) {
locationRequest = new LocationRequest();
locationRequest.setInterval(1100);
locationRequest.setFastestInterval(1100);
locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
}
activity_maps.xml ：
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity"
class="com.google.android.gms.maps.SupportMapFragment"/>
已将其添加到我的 AndroidManifest.xml 中：
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
感谢您的帮助。
答案 0 :(得分：0)
因此，您已经完成了几乎所有的工作。您只需要再走一步即可。
首先要了解的是，将setMyLocationEnabled设置为true时会在地图上添加该位置指南针按钮。这是您单击以查找当前位置的内容。好的开始。
初始化地图时，还需要将相机设置为当前位置。
if(locationPermissionGranted){
Task<Location> locationResult = fusedLocationProviderClient.getLastLocation();
locationResult.addOnCompleteListener(getActivity(), new OnCompleteListener<Location>() {
@Override
public void onComplete(@NonNull Task<Location> task) {
if(task.isSuccessful()){
// Set the maps camera to current location
lastKnownLocation = task.getResult();
map.moveCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude()), 12));
}
else{
Log.d(TAG, "Current location is null");
Log.e(TAG,"Exception: %s", task.getException());
map.moveCamera(CameraUpdateFactory.newLatLngZoom(defaultLocation, 12));
map.getUiSettings().setMyLocationButtonEnabled(false);
}
}
});
}
尝试一下。首先，请确保您已授予位置权限。然后尝试找到最后一个已知的位置。 （如果您使用的是模拟器，请在尝试使用此代码之前先尝试打开Google Maps。从未在模拟器上启动过位置服务）。它将尝试获取您的当前位置。如果成功，它将照相机移动到该位置，如果失败，我将为地图设置默认位置，而不是在海洋中打开。
private LatLng defaultLocation = new LatLng(41.651031, -83.541939);
希望这会有所帮助。
答案 1 :(得分：0)
我想，我是这样解决的。
我已经修改了 onMapReady ：
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {
@Override
public void onMyLocationChange(Location arg0) {
float zoomLevel = 15.0f;
LatLng latLng = new LatLng(arg0.getLatitude(), arg0.getLongitude());
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoomLevel));
}
});
}
/*disabling toolbar (it is used to continue using this app without having to
use the official google maps app)*/
mMap.getUiSettings().setMapToolbarEnabled(false);
然后，当我打开我的应用程序时，会将相机设置在我的当前位置。 非常感谢。
答案 2 :(得分：0)
[前提条件]-确保您已授予位置权限，并且位置服务已打开。
public void onMapReady(GoogleMap googleMap){
mMap = googleMap;
// You can register for Location Change Once the location is updated,
// Fetch lat, lng from it. Once you have lat,lng convert it into `LatLng`
LatLng currLatLng = fetchedFromAPI();
CameraPosition newPos =
new CameraPosition.Builder()
.target(currLatLng)
.build();
if (showAnimation){
mMap.animateCamera(CameraUpdateFactory.newCameraPosition(newPos));
}else{
mMap.moveCamera(CameraUpdateFactory.newCameraPosition(newPos));
}
}