我是 android 初学者,我按照教程并尝试使用 android 在谷歌地图上显示当前位置。下面是代码:
MainActivity.java
package com.example.android_gps_location_detection;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
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.MarkerOptions;
@SuppressLint("NewApi")
public class MainActivity extends FragmentActivity {
GoogleMap map;
LocationManager lm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.mapView);
map = mapFragment.getMap();
map.setMyLocationEnabled(true);
LocationListener ll = new LocationListener() {
@Override
public void onStatusChanged(String provider, int status,
Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onLocationChanged(Location location) {
Toast.makeText(getApplicationContext(),
location.getLatitude() + " " + location.getLongitude(),
Toast.LENGTH_LONG).show();
map.addMarker(new MarkerOptions()
.position(
new LatLng(location.getLatitude(), location
.getLongitude()))
.title("my position")
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
map.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(
location.getLatitude(), location.getLongitude()), 15.0f));
}
};
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<fragment
android:id="@+id/mapView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.SupportMapFragment"
/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyBqwF4D-JhpA32_OL8Bw0dKDqc7Jm0CWHQ"/>
<uses-library android:name="com.google.android.maps" />
<activity
android:name="com.example.android_gps_location_detection.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<!--
The following two permissions are not required to use
Google Maps Android API v2, but are recommended.
-->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<permission
android:name="com.ram.mapsv2whereami.permission.MAPS_RECEIVE"
android:protectionLevel="signature" />
<uses-permission android:name="com.ram.mapsv2whereami.permission.MAPS_RECEIVE" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
</manifest>
我得到了这个错误 map.setMyLocationEnabled(true); 这一行得到了 NullPointerException,我怀疑 getMap() 返回 null。我做了一些研究,发现有人建议使用 SupportMapFragment。Google Play 服务已过期。需要 3225100 但找到 3158130
项目构建目标是 Google API 级别 18 平台 4.3 我的 AVD 是 Target-google api 级别 18