如何在 Google 地图 API for Android 中自动放大到当前位置？
How do I zoom in automatically to the current location in Google Maps API for Android?
我在AndroidStudio中集成了Google地图API，它也能找到当前位置，但我想增加缩放级别，以便我可以查看我当前的位置更加清晰和精确。如何增加缩放级别？
您可以在下面找到我的代码：
package com.example.umar.testgoogle;
import android.location.Location;
import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity extends FragmentActivity implements
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
public static final String TAG = MapsActivity.class.getSimpleName();
/*
* Define a request code to send to Google Play services
* This code is returned in Activity.onActivityResult
*/
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
private GoogleMap mMap; // Might be null if Google Play services APK is
// not available.
private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
setUpMapIfNeeded();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
// Create the LocationRequest object
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(10 * 1000) // 10 seconds, in milliseconds
.setFastestInterval(1 * 1000); // 1 second, in milliseconds
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
mGoogleApiClient.connect();
}
@Override
protected void onPause() {
super.onPause();
if (mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
mGoogleApiClient.disconnect();
}
}
/**
* Sets up the map if it is possible to do so (i.e., the Google Play
* services APK is correctly installed) and the map has not already
* been instantiated.. This will ensure that we only ever call
* {@link #setUpMap()} once when {@link #mMap} is not null.
* <p/>
* If it isn't installed {@link SupportMapFragment} (and
* {@link com.google.android.gms.maps.MapView MapView}) will show a
* prompt for the user to install/update the Google Play services
* APK on their device.
* <p/>
* A user can return to this FragmentActivity after following the
* prompt and correctly installing/updating/enabling the Google
* Play services. Since the FragmentActivity may not have been
* completely destroyed during this process (it is likely that it
* would only be stopped or paused), {@link #onCreate(Bundle)} may
* not be called again so we should call this method in
* {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
/**
* This is where we can add markers or lines, add listeners or move
* the camera. In this case, we just add a marker near Africa.
* <p/>
* This should only be called once and when we are sure
* that {@link #mMap} is not null.
*/
private void setUpMap() {
mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
}
private void handleNewLocation(Location location) {
Log.d(TAG, location.toString());
double currentLatitude = location.getLatitude();
double currentLongitude = location.getLongitude();
LatLng latLng = new LatLng(currentLatitude, currentLongitude);
//mMap.addMarker(new MarkerOptions().position(new LatLng(currentLatitude, currentLongitude)).title("Current Location"));
MarkerOptions options = new MarkerOptions()
.position(latLng)
.title("I am here!");
mMap.addMarker(options);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
}
@Override
public void onConnected(Bundle bundle) {
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location == null) {
LocationServices.FusedLocationApi.requestLocationUpdates(
mGoogleApiClient, mLocationRequest, this);
}
else {
handleNewLocation(location);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(
this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
}
catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
}
else {
/*
* If no resolution is available, display a dialog to the
* user with the error.
*/
Log.i(TAG, "Location services connection failed with code " +
connectionResult.getErrorCode());
}
}
@Override
public void onLocationChanged(Location location) {
handleNewLocation(location);
}
}
更改自：
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
至：
float zoomLevel = 16.0f; //This goes up to 21
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoomLevel));
public static CameraUpdate newLatLngZoom (LatLng latLng, float zoom)
Returns a CameraUpdate that moves the center of the screen to a
latitude and longitude specified by a LatLng object, and moves to the
given zoom level.
Parameters latLng a LatLng object containing the desired latitude and
longitude. zoom the desired zoom level, in the range of 2.0 to 21.0.
Values below this range are set to 2.0, and values above it are set to
21.0. Increase the value to zoom in. Not all areas have tiles at the largest zoom levels. Returns a CameraUpdate containing the
transformation.
或者你也可以使用animateCamerma方法来获得动画缩放效果。
// This is method returns the lastKnownlocation and store it in location object from where then you can retrive latitute and longitude.
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 20.0f));
我在AndroidStudio中集成了Google地图API，它也能找到当前位置，但我想增加缩放级别，以便我可以查看我当前的位置更加清晰和精确。如何增加缩放级别？
您可以在下面找到我的代码：
package com.example.umar.testgoogle;
import android.location.Location;
import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity extends FragmentActivity implements
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
public static final String TAG = MapsActivity.class.getSimpleName();
/*
* Define a request code to send to Google Play services
* This code is returned in Activity.onActivityResult
*/
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
private GoogleMap mMap; // Might be null if Google Play services APK is
// not available.
private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
setUpMapIfNeeded();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
// Create the LocationRequest object
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(10 * 1000) // 10 seconds, in milliseconds
.setFastestInterval(1 * 1000); // 1 second, in milliseconds
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
mGoogleApiClient.connect();
}
@Override
protected void onPause() {
super.onPause();
if (mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
mGoogleApiClient.disconnect();
}
}
/**
* Sets up the map if it is possible to do so (i.e., the Google Play
* services APK is correctly installed) and the map has not already
* been instantiated.. This will ensure that we only ever call
* {@link #setUpMap()} once when {@link #mMap} is not null.
* <p/>
* If it isn't installed {@link SupportMapFragment} (and
* {@link com.google.android.gms.maps.MapView MapView}) will show a
* prompt for the user to install/update the Google Play services
* APK on their device.
* <p/>
* A user can return to this FragmentActivity after following the
* prompt and correctly installing/updating/enabling the Google
* Play services. Since the FragmentActivity may not have been
* completely destroyed during this process (it is likely that it
* would only be stopped or paused), {@link #onCreate(Bundle)} may
* not be called again so we should call this method in
* {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
/**
* This is where we can add markers or lines, add listeners or move
* the camera. In this case, we just add a marker near Africa.
* <p/>
* This should only be called once and when we are sure
* that {@link #mMap} is not null.
*/
private void setUpMap() {
mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
}
private void handleNewLocation(Location location) {
Log.d(TAG, location.toString());
double currentLatitude = location.getLatitude();
double currentLongitude = location.getLongitude();
LatLng latLng = new LatLng(currentLatitude, currentLongitude);
//mMap.addMarker(new MarkerOptions().position(new LatLng(currentLatitude, currentLongitude)).title("Current Location"));
MarkerOptions options = new MarkerOptions()
.position(latLng)
.title("I am here!");
mMap.addMarker(options);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
}
@Override
public void onConnected(Bundle bundle) {
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location == null) {
LocationServices.FusedLocationApi.requestLocationUpdates(
mGoogleApiClient, mLocationRequest, this);
}
else {
handleNewLocation(location);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(
this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
}
catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
}
else {
/*
* If no resolution is available, display a dialog to the
* user with the error.
*/
Log.i(TAG, "Location services connection failed with code " +
connectionResult.getErrorCode());
}
}
@Override
public void onLocationChanged(Location location) {
handleNewLocation(location);
}
}
更改自：
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
至：
float zoomLevel = 16.0f; //This goes up to 21
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoomLevel));
public static CameraUpdate newLatLngZoom (LatLng latLng, float zoom)
Returns a CameraUpdate that moves the center of the screen to a latitude and longitude specified by a LatLng object, and moves to the given zoom level.
Parameters latLng a LatLng object containing the desired latitude and longitude. zoom the desired zoom level, in the range of 2.0 to 21.0. Values below this range are set to 2.0, and values above it are set to 21.0. Increase the value to zoom in. Not all areas have tiles at the largest zoom levels. Returns a CameraUpdate containing the transformation.
或者你也可以使用animateCamerma方法来获得动画缩放效果。
// This is method returns the lastKnownlocation and store it in location object from where then you can retrive latitute and longitude.
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 20.0f));