开始研究google地图，做下笔记
准备工作：
1.新建android studio 项目，选择模板Google Maps Activity
2.注册google地图账号，填写key
3.运行项目，google被墙，显示不出来，需要手机安装谷歌服务框架，手机vpn，才能正常显示地图
核心代码

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

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.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends AppCompatActivity implements OnMapReadyCallback {
    private static final String TAG = MapsActivity.class.getSimpleName();
    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Retrieve the content view that renders the map.
        setContentView(R.layout.activity_maps);

        // Build the map.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

    }


    /**
     * Manipulates the map when it's available.
     * This callback is triggered when the map is ready to be used.
     */
    @Override
    public void onMapReady(GoogleMap map) {
        mMap = map;
        // Prompt the user for permission.
        getLocationPermission();

    }

    /**
     * Prompts the user for permission to use the device location.
     */
    private void getLocationPermission() {
        /*
         * Request location permission, so that we can get the location of the
         * device. The result of the permission request is handled by a callback,
         * onRequestPermissionsResult.
         */
        if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
                android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            requestLocationUpdate();
        } else {
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, 1);
        }
    }

    /**
     * Handles the result of the request for location permissions.
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
        if (requestCode == 1) {
            requestLocationUpdate();
        }
    }


    @SuppressLint("MissingPermission")
    private void requestLocationUpdate() {

        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        boolean enabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        if (enabled) {
            locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 2000, 10, new LocationListener() {
                @Override
                public void onLocationChanged(Location location) {
                    if (location == null) {
                        Toast.makeText(MapsActivity.this, "未有定位", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
                    mMap.addMarker(new MarkerOptions().position(latLng).title("Marker of me"));
                    mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
                    mMap.animateCamera(CameraUpdateFactory.zoomTo(15));

                }

                @Override
                public void onStatusChanged(String provider, int status, Bundle extras) {

                }

                @Override
                public void onProviderEnabled(String provider) {

                }

                @Override
                public void onProviderDisabled(String provider) {

                }
            });
        }
    }


}