Android - 缩放到用户位置并显示地图

Question

我是一个初学Android的人。所以请帮助！现在单击按钮时，相机将缩放到用户位置，但是我希望它在创建活动后进行缩放。如果用户移动，则更改位置。

package com.example.mapdemo; 

import android.Manifest; 
import android.content.pm.PackageManager; 
import android.content.res.Resources; 
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.util.Log; 
import android.widget.Toast; 

import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.GoogleMap.OnMyLocationButtonClickListener; 
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.MapStyleOptions; 
import com.google.android.gms.maps.model.MarkerOptions; 



public class MyLocationDemoActivity extends AppCompatActivity 
     implements 
     OnMyLocationButtonClickListener, 
     OnMapReadyCallback, 
     ActivityCompat.OnRequestPermissionsResultCallback { 
    double lat=0,lng=0; 
    /** 
    * Request code for location permission request. 
    * 
    * @see #onRequestPermissionsResult(int, String[], int[]) 
     */ 
    private static final int LOCATION_PERMISSION_REQUEST_CODE = 1; 

    /** 
* Flag indicating whether a requested permission has been denied after returning in 
* {@link #onRequestPermissionsResult(int, String[], int[])}. 
*/ 
private boolean mPermissionDenied = false; 

private GoogleMap mMap; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.my_location_demo); 

    SupportMapFragment mapFragment = 
      (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map); 
    mapFragment.getMapAsync(this); 
} 

@Override 
public void onMapReady(GoogleMap map) { 
    mMap = map; 

    try { 
     // Customise the styling of the base map using a JSON object defined 
     // in a raw resource file. 
     boolean success = mMap.setMapStyle(
       MapStyleOptions.loadRawResourceStyle(
         this, R.raw.mapstyle_night)); 

     if (!success) { 
      Log.e("MapsActivityRaw", "Style parsing failed."); 
     } 
    } catch (Resources.NotFoundException e) { 
     Log.e("MapsActivityRaw", "Can't find style.", e); 
    } 
    //mMap.setOnMyLocationButtonClickListener(this); 
    enableMyLocation(); 
    LatLng loc = new LatLng(lat, lng); 
    mMap.addMarker(new MarkerOptions().position(loc).title("New Marker")); 
    mMap.moveCamera(CameraUpdateFactory.newLatLng(loc)); 
} 

/** 
* Enables the My Location layer if the fine location permission has been granted. 
*/ 
private void enableMyLocation() { 
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) 
      != PackageManager.PERMISSION_GRANTED) { 
     // Permission to access the location is missing. 
     PermissionUtils.requestPermission(this, LOCATION_PERMISSION_REQUEST_CODE, 
       Manifest.permission.ACCESS_FINE_LOCATION, true); 
    } else if (mMap != null) { 
     // Access to the location has been granted to the app. 
     mMap.setMyLocationEnabled(true); 
    } 
} 

@Override 
public boolean onMyLocationButtonClick() { 
    Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show(); 
    // Return false so that we don't consume the event and the default behavior still occurs 
    // (the camera animates to the user's current position). 
    return false; 
} 


@Override 
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, 
     @NonNull int[] grantResults) { 
    if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) { 
     return; 
    } 

    if (PermissionUtils.isPermissionGranted(permissions, grantResults, 
      Manifest.permission.ACCESS_FINE_LOCATION)) { 
     // Enable the my location layer if the permission has been granted. 
     enableMyLocation(); 
    } else { 
     // Display the missing permission error dialog when the fragments resume. 
     mPermissionDenied = true; 
    } 
} 

@Override 
protected void onResumeFragments() { 
    super.onResumeFragments(); 
    if (mPermissionDenied) { 
     // Permission was not granted, display error dialog. 
     showMissingPermissionError(); 
     mPermissionDenied = false; 
    } 
} 

/** 
* Displays a dialog with error message explaining that the location permission is missing. 
*/ 
private void showMissingPermissionError() { 
    PermissionUtils.PermissionDeniedDialog 
      .newInstance(true).show(getSupportFragmentManager(), "dialog"); 
} 

}

Answer 1

可以使用XML设置缩放属性太像这样：

<fragment xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:map="http://schemas.android.com/apk/res-auto" 
     android:name="com.google.android.gms.maps.SupportMapFragment" 
     android:id="@+id/map" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     map:cameraZoom="13" 
     map:mapType="normal" 
     map:uiCompass="true" 
     map:uiRotateGestures="true" 
     map:uiScrollGestures="false" 
     map:uiTiltGestures="true" 
     map:uiZoomControls="false" 
     map:uiZoomGestures="true"/> 

Answer 2

使用以下链接以获取您的当前位置：

http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/

现在，当您得到您当前的纬度和经度使用以下行来放大你的当前位置：

mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude,longitude),16)); 
mMap.getUiSettings().setZoomControlsEnabled(true); 

之后，使用setOnMyL用户在移动时更改标记的映射的ocationChangeListener（）方法。