Question

我无法在平板电脑上运行google maps api v2。我似乎无法找到错误的位置。应用程序崩溃，因为它总是在选项卡中意外停止。有人能帮帮我吗？我正在使用FragmentActivity。

此外，我已经清理了项目，并确保我导入了google-play-service-lib。我不明白我是如何得到错误的。

Logcat：

01-08 12:54:05.450: E/AndroidRuntime(25497): FATAL EXCEPTION: main
01-08 12:54:05.450: E/AndroidRuntime(25497): java.lang.RuntimeException: Unable to start     
activity ComponentInfo{com.example.googlemaps/com.example.googlemaps.MainActivity}: 
java.lang.NullPointerException
01-08 12:54:05.450: E/AndroidRuntime(25497):at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
android.app.ActivityThread.access$600(ActivityThread.java:141)
01-08 12:54:05.450: E/AndroidRuntime(25497):at   
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
01-08 12:54:05.450: E/AndroidRuntime(25497):at 
android.os.Handler.dispatchMessage(Handler.java:99)
01-08 12:54:05.450: E/AndroidRuntime(25497):at android.os.Looper.loop(Looper.java:137)  
01-08 12:54:05.450: E/AndroidRuntime(25497):at 
android.app.ActivityThread.main(ActivityThread.java:5103)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
java.lang.reflect.Method.invokeNative(Native Method)
01-08 12:54:05.450: E/AndroidRuntime(25497):at 
java.lang.reflect.Method.invoke(Method.java:525)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
dalvik.system.NativeStart.main(Native Method)
01-08 12:54:05.450: E/AndroidRuntime(25497): Caused by: java.lang.NullPointerException
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
com.example.googlemaps.MainActivity.setUpMap(MainActivity.java:47)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
com.example.googlemaps.MainActivity.setUpMapIfNeeded(MainActivity.java:33)
01-08 12:54:05.450: E/AndroidRuntime(25497):at 
com.example.googlemaps.MainActivity.onCreate(MainActivity.java:25)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
android.app.Activity.performCreate(Activity.java:5133)
01-08 12:54:05.450: E/AndroidRuntime(25497): at 
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
01-08 12:54:05.450: E/AndroidRuntime(25497): at  
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
01-08 12:54:05.450: E/AndroidRuntime(25497):    ... 11 more
01-08 12:56:09.040: E/MPL-storeload(440): calData from inv_save_mpl_states, size=2

主要：

package com.example.googlemaps;

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;

import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.Menu;
import android.support.v4.app.FragmentActivity;


public class MainActivity extends FragmentActivity {

private GoogleMap googleMap;

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

private void setUpMapIfNeeded() {
    // TODO Auto-generated method stub
    if (googleMap == null) {
        googleMap = ((SupportMapFragment) 
        getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
        if (googleMap != null) {
            setUpMap();
        }
    }
}

private void setUpMap() {
    // TODO Auto-generated method stub
    googleMap.setMyLocationEnabled(true);

    LocationManager locationManager = (LocationManager) 
            getSystemService(LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    String provider = locationManager.getBestProvider(criteria, true);
    Location myLocation = locationManager.getLastKnownLocation(provider);
    googleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
    double latitude = myLocation.getLatitude();
    double longitude = myLocation.getLongitude();

    LatLng latLng = new LatLng(latitude, longitude);
    googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    googleMap.animateCamera(CameraUpdateFactory.zoomTo(10));
    googleMap.addMarker(new MarkerOptions().position(new LatLng(latitude, 
            longitude)).title("You are here!"));
}

@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：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.googlemaps"
android:versionCode="1"
android:versionName="1.0" >

<permission
    android:name="com.example.googlemaps.permission.MAPS_RECEIVE"
    android:protectionLevel="signature" />

<uses-permission android:name="com.example.googlemaps.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" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="16" />

<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.googlemaps.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.gms.version"
        android:value="@integer/google_play_services_version" />

    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="AIzaSyC5RVOfXZGfsFHoMosdF_mOOcfaqUZEJJU" />
</application>

</manifest>

布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<fragment
    android:name="com.google.android.gms.maps.SupportMapFragment"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    />

 </LinearLayout>

Answer 1

LocationManager locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String provider = locationManager.getBestProvider(criteria, true);
Location myLocation = locationManager.getLastKnownLocation(provider);

在上面的代码中，

您已为条件创建了新对象，但未指定条件。这可能导致了问题

请尝试以下代码

LocationManager locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) 
{
     Location location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
     if (location != null) 
     {
       latitude = location.getLatitude();
       longitude = location.getLongitude();
     }
}

无法运行谷歌地图apiv2

1 个答案: