Android 在开发简单的Google地图应用程序时获取NullPointerException
我是Android的谷歌地图新手,我正在使用Android开发简单的谷歌地图应用程序。(我正在使用谷歌地图V2) 我提到这个链接: 我还尝试使用MapFragment而不是SupportMapFragment,但是, 我在第24行遇到NullPointerException:Android 在开发简单的Google地图应用程序时获取NullPointerException,android,google-maps,android-maps-v2,Android,Google Maps,Android Maps V2,我是Android的谷歌地图新手,我正在使用Android开发简单的谷歌地图应用程序。(我正在使用谷歌地图V2) 我提到这个链接: 我还尝试使用MapFragment而不是SupportMapFragment,但是, 我在第24行遇到NullPointerException: line 24: googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE); 我哪里做错了?请建议我修改代码(如果有) 以下是我面临异常的MainActivity代码 pa
line 24: googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE);
我哪里做错了?请建议我修改代码(如果有)
以下是我面临异常的MainActivity代码
package com.example.mymap;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapsInitializer;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.SupportMapFragment;
import android.os.Bundle;
import android.app.Activity;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
public class MainActivity extends FragmentActivity {
GoogleMap googleMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MapsInitializer.initialize(getApplicationContext());
googleMap = ((SupportMapFragment)(getSupportFragmentManager().findFragmentById(R.id.map))).getMap();
LatLng latLng = new LatLng(-33.796923, 150.922433);
**googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE);**
googleMap.addMarker(new MarkerOptions()
.position(latLng)
.title("My Spot")
.snippet("This is my spot!")
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
googleMap.getUiSettings().setCompassEnabled(true);
googleMap.getUiSettings().setZoomControlsEnabled(true);
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
清单文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mymap"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<permission
android:name="com.example.mymap.permission.MAPS_RECEIVE"
android:protectionLevel="signature"/>
<uses-permission android:name="com.example.mymap.permission.MAPS_RECEIVE"/>
<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"/>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.mymap.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>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="My API Key"/>
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
</application>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"/>
</RelativeLayout>
布局文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mymap"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<permission
android:name="com.example.mymap.permission.MAPS_RECEIVE"
android:protectionLevel="signature"/>
<uses-permission android:name="com.example.mymap.permission.MAPS_RECEIVE"/>
<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"/>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.mymap.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>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="My API Key"/>
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
</application>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"/>
</RelativeLayout>
以下是日志cat输出:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mymap"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<permission
android:name="com.example.mymap.permission.MAPS_RECEIVE"
android:protectionLevel="signature"/>
<uses-permission android:name="com.example.mymap.permission.MAPS_RECEIVE"/>
<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"/>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.mymap.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>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="My API Key"/>
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
</application>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"/>
</RelativeLayout>
而不是这个:-
googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE);
写下:-
googleMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
参考这一点,它将对您大有帮助。您的测试设备上是否安装了Google Play服务? 否则,getMap()将返回null。 如果在模拟器上进行测试,则只有Android版本4.2.2及以上的模拟器安装了Google Play服务。更改此设置
googleMap = ((SupportMapFragment)(getSupportFragmentManager().findFragmentById(R.id.map))).getMap();
到
也改变了这一点
googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE);
到
发布你的布局文件..在哪一行你得到了NPE?@Piyush:在第24行。我写的这封信有问题。。googleMap.setMapType(googleMap.MAP_TYPE_SATELLITE);@我已经编辑了我的问题。我已经提供了我的布局文件。是的,我已经安装了谷歌播放服务。。我已经为froyowrite安装了google play服务和google play服务:-google地图=((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map)).getMap()@Rohit发布您的错误,并将其应用到物理device@Rohit更改后,您必须再次构建新的apk并卸载旧的apk。请参阅我发布的代码段,它是日志cat内容。(在第24行显示NullPointerException)应用程序正在物理设备上运行。。。但不是在emulator上…所以现在,我如何在emulator上执行它…这证明了在编写的代码中没有错误。。。那么为什么emulator无法运行它并引发异常呢??有什么想法吗???@Rohit你需要在你的
模拟器中设置不同的google\u play\u lirary\u lib
。但是我建议你千万不要在你的模拟器中测试这个错误,因为模拟器没有找到google\u play\u lirary\u lib类