Question

我严格遵循谷歌地图API规则，并根据要求导入谷歌播放服务库。在通过Android SDK意外更新谷歌存储库和谷歌播放服务后，有如下错误。我该怎么做才能纠正这个问题？我私下打开了谷歌播放服务lib项目的包。它显示com.android。 UNstubJava，因为没有其他特殊类支持我的项目。

AndroidManifest.xml

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

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <permission 
        android:name="com.larry.proto.maptest.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-permission android:name="com.larry.proto.maptest.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-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" >
        <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="AIzaSyBUHtViyAqpiOofdE0526j4Q-oO9aLut0I" />

        <activity
            android:name="com.larry.proto.maptest.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>

</manifest>

res / Laylout / activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:name="com.google.android.gms.maps.MapFragment"/>

Logcat消息

05-21 14:31:23.636: E/AndroidRuntime(9435): Process: com.larry.proto.maptest, PID: 9435
05-21 14:31:23.636: E/AndroidRuntime(9435): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.larry.proto.maptest/com.larry.proto.maptest.MainActivity}: java.lang.NullPointerException
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.os.Handler.dispatchMessage(Handler.java:102)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.os.Looper.loop(Looper.java:136)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread.main(ActivityThread.java:5017)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at java.lang.reflect.Method.invokeNative(Native Method)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at java.lang.reflect.Method.invoke(Method.java:515)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at dalvik.system.NativeStart.main(Native Method)
05-21 14:31:23.636: E/AndroidRuntime(9435): Caused by: java.lang.NullPointerException
05-21 14:31:23.636: E/AndroidRuntime(9435):     at com.larry.proto.maptest.MainActivity.onCreate(MainActivity.java:47)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.Activity.performCreate(Activity.java:5231)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-21 14:31:23.636: E/AndroidRuntime(9435):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)

代码

package com.larry.proto.maptest;

import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener;
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;
public class MainActivity extends FragmentActivity  implements OnMapClickListener, OnMapLongClickListener {


    final int RQS_GooglePlayServices = 1;

    private GoogleMap myMap;
    Location myLocation;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myMap =  ((SupportMapFragment)  getSupportFragmentManager().findFragmentById(R.id.map))
                           .getMap();
        myMap.setMyLocationEnabled(true);
        myMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
    }

    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    @Override

    protected void onResume() {

        super.onResume();



        int resultCode = GooglePlayServicesUtil

                .isGooglePlayServicesAvailable(getApplicationContext());



        if (resultCode == ConnectionResult.SUCCESS) {

            Toast.makeText(getApplicationContext(),

                    "isGooglePlayServicesAvailable SUCCESS", Toast.LENGTH_LONG)

                    .show();

        } else {

            GooglePlayServicesUtil.getErrorDialog(resultCode, this,

                    RQS_GooglePlayServices);

        }



    }


    @Override

    public void onMapClick(LatLng point) {

        myMap.animateCamera(CameraUpdateFactory.newLatLng(point));

        Toast.makeText(getApplicationContext(), point.toString(),

                Toast.LENGTH_LONG).show();

    }



    @Override

    public void onMapLongClick(LatLng point) {

        myMap.addMarker(new MarkerOptions()

        .position(point)

        .title("You are here")           

        .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));  





        Toast.makeText(getApplicationContext(),

                "New marker added@" + point.toString(), Toast.LENGTH_LONG)

                .show();



    }



}

Answer 1

根据你的评论，你有这个

android:name="com.google.android.gms.maps.MapFragment

应该是

android:name="com.google.android.gms.maps.SupportMapFragment

因为你有

 myMap =  ((SupportMapFragment)  getSupportFragmentManager().findFragmentById(R.id.map))
                       .getMap();

getMap()返回null。

在检查了Google Play服务的可用性后初始化GoogleMap对象

GoogleMap只能在底层使用getMap（）获取加载了地图系统，并且片段中的基础视图存在。该类自动初始化地图系统和视图; 但是，因为这样，你就无法保证准备就绪取决于Google Play服务APK的可用性。如果一个 GoogleMap不可用，getMap（）将返回null。

编辑：

看着你的清单

android:minSdkVersion="14"

所以改变这个

public class MainActivity extends FragmentActivity

要

public class MainActivity extends Activity

然后回到

android:name="com.google.android.gms.maps.MapFragment

同时更改此

myMap =  ((SupportMapFragment)  getSupportFragmentManager().findFragmentById(R.id.map))
                   .getMap();

到

myMap =  ((MapFragment)  getFragmentManager().findFragmentById(R.id.map))
                   .getMap();

您不需要以下

<permission 
    android:name="com.larry.proto.maptest.permission.MAPS_RECEIVE"
    android:protectionLevel="signature" />

<uses-permission android:name="com.larry.proto.maptest.permission.MAPS_RECEIVE" />

在onResume

中初始化GoogleMap对象

if (resultCode == ConnectionResult.SUCCESS) {
       // intialize if success
}

Answer 2

如果您的minsdk<12和/或您希望Backward Compability Support那么

你应该改变这个

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

与

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

Google Map不能为MapFragment Map的null异常

2 个答案: