Question

我已经阅读了文件 https://developers.google.com/maps/documentation/android/start 我在eclipse中创建了项目android，逐步创建了folow文档，但是当我无法运行项目时。

示例错误java.lang.NullPointerException

错误日志

03-20 15:13:39.332: D/AndroidRuntime(28930): Shutting down VM
03-20 15:13:39.332: W/dalvikvm(28930): threadid=1: thread exiting with uncaught exception (group=0x2b542210)
03-20 15:13:39.352: E/AndroidRuntime(28930): FATAL EXCEPTION: main
03-20 15:13:39.352: E/AndroidRuntime(28930): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.my_ap/com.mrbuoi.my_ap.MainActivity}: java.lang.NullPointerException
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread.access$600(ActivityThread.java:127)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.os.Looper.loop(Looper.java:137)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread.main(ActivityThread.java:4441)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at java.lang.reflect.Method.invokeNative(Native Method)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at java.lang.reflect.Method.invoke(Method.java:511)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:565)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at dalvik.system.NativeStart.main(Native Method)
03-20 15:13:39.352: E/AndroidRuntime(28930): Caused by: java.lang.NullPointerException
03-20 15:13:39.352: E/AndroidRuntime(28930):    at com.mrbuoi.my_ap.MainActivity.onCreate(MainActivity.java:31)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.Activity.performCreate(Activity.java:4465)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-20 15:13:39.352: E/AndroidRuntime(28930):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)
03-20 15:13:39.352: E/AndroidRuntime(28930):    ... 11 more

-----文件AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.my_ap"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true"/>
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="14" />

<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"/>

<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="15" />
    <meta-data
    android:name="com.google.android.maps.v2.API_KEY"
    android:value="MY_APIKEY"/>
    <activity
        android:name="com.mrbuoi.may_ap.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>

----文件MainActivity.java

package com.mrbuoi.my_ap;

import com.example.my_ap.R;
import com.google.android.gms.maps.*;
import com.google.android.gms.maps.model.*;
import android.annotation.TargetApi;
import android.app.Activity;
import android.os.Bundle;

import android.os.Build;

public class MainActivity extends Activity {

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
     GoogleMap map = ((MapFragment) getFragmentManager()
                .findFragmentById(R.id.map)).getMap();

        LatLng sydney = new LatLng(-33.867, 151.206);

        map.setMyLocationEnabled(true);
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney, 13));

        map.addMarker(new MarkerOptions()
                .title("Sydney")
                .snippet("The most populous city in Australia.")
                .position(sydney));
}
}

----- File Fragment_main.xml

<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="com.mrbuoi.my_ap.MainActivity$PlaceholderFragment" >

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

</RelativeLayout>

更新activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mrbuoi.bactai_app.MainActivity"
tools:ignore="MergeRootFrame" />

有人有小费吗？ Tks

更新
@PiYusH GuPtA，我试过这个，但这不起作用我的错误日志

03-20 15:24:42.922: E/AndroidRuntime(29491): FATAL EXCEPTION: main
03-20 15:24:42.922: E/AndroidRuntime(29491): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.my_ap/com.mrbuoi.my_ap.MainActivity}: java.lang.NullPointerException
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread.access$600(ActivityThread.java:127)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.os.Looper.loop(Looper.java:137)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread.main(ActivityThread.java:4441)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at java.lang.reflect.Method.invokeNative(Native Method)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at java.lang.reflect.Method.invoke(Method.java:511)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:565)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at dalvik.system.NativeStart.main(Native Method)
03-20 15:24:42.922: E/AndroidRuntime(29491): Caused by: java.lang.NullPointerException
03-20 15:24:42.922: E/AndroidRuntime(29491):    at com.mrbuoi.my_ap.MainActivity.onCreate(MainActivity.java:22)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.Activity.performCreate(Activity.java:4465)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-20 15:24:42.922: E/AndroidRuntime(29491):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)
03-20 15:24:42.922: E/AndroidRuntime(29491):    ... 11 more

Answer 1

您需要为您的课程扩展 FragmentActivity ，而不是活动。

您必须添加的其他内容

  <uses-feature
    android:glEsVersion="0x00020000"
    android:required="true" />

在您的清单文件中。

同时更改此

  if(map!=null){

   LatLng sydney = new LatLng(-33.867, 151.206);

   map.setMyLocationEnabled(true);
   map.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney, 13));

   map.addMarker(new MarkerOptions()
            .title("Sydney")
            .snippet("The most populous city in Australia.")
            .position(sydney));

  }

的更新： 的

从此处更改

setContentView(R.layout.activity_main);

到

setContentView(R.layout.Fragment_main);

使用此

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.mrbuoi.bactai_app.MainActivity" tools:ignore="MergeRootFrame" > <include layout="@layout/Fragment_main"></include> </FrameLayout>

Answer 2

首先，您需要将Activity更改为FragmentActivity，同时在课堂上进行扩展，如下所示：

public class MainActivity extends FragmentActivity{

此外，包含GoogleMap视图的布局展开的名称为Fragment_main，并且在您的活动中，您已经夸大了错误的布局activity_main。

因此，请更改setContentView布局

setContentView(R.layout.activity_main);

到

setContentView(R.layout.Fragment_main);

此外，由于您的最低api级别低于11，因此您必须使用SupportMapFragment加载地图，如下所示：

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

<强>编辑：

在你的清单中更改下面的行

<meta-data
    android:name="com.google.android.gms.version"
    android:value="15" />

到

<meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" />

同时在Fragment布局文件中更改您的fragment_main班级名称。

<fragment
      android:id="@+id/map"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:name="com.google.android.gms.maps.SupportMapFragment"/>

无法使用Google Map android API V2创建项目

2 个答案: