使用 FragmentManager 引用 GoogleMap 片段时出现 Android 致命错误

Question

我能够使用以下 Activity 布局成功地初始化 GoogleMap API 2.0：

<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<FrameLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/fragment_container">

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

</FrameLayout>

</RelativeLayout>

现在我正在尝试引用此片段以使用以下代码设置几个选项：

    private GoogleMap gMap;
.
.
.

    private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (gMap == null) {
        gMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.ganbi_map)).getMap();
        // Check if we were successful in obtaining the map.
        if (gMap != null) {
            // The Map is verified. It is now safe to manipulate the map.
            // Load map preferences
            Log.d("Info","Map ready for initailization");

        }
    }
}

这会导致致命错误，并且跟踪归咎于以下行：gMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.ganbi_map)).getMap();

有什么建议吗？

Answer 1

试试这个

 gMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.ganbi_map)).getMap();

Answer 2

替换下面的行：

gMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.ganbi_map)).getMap();

到这一行：

 gMap = ((SupportMapFragment) getFragmentManager().findFragmentById(R.id.ganbi_map)).getMap();

Answer 3

Java 代码

package com.dilip.googlemapsv2;

import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends FragmentActivity {

    // Google Map
    private GoogleMap googleMap;


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

        try {
            // Loading map
            initilizeMap();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }



    /**
    * function to load map. If map is not created it will create it for you
    * */
   private void initilizeMap() {
       if (googleMap == null) {
           //googleMap = ((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();
           googleMap = ((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();

           // check if map is created successfully or not
           if (googleMap == null) {
               Toast.makeText(getApplicationContext(),"Sorry! unable to create maps", Toast.LENGTH_SHORT).show();
           }
       }
   }

   @Override
   public void onResume() {
       super.onResume();
       GooglePlayServicesUtil.isGooglePlayServicesAvailable(this.getApplicationContext());
       initilizeMap();
   }

    @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);
    }
}

XML 代码

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


    <fragment
        android:id="@+id/map"

        android:name="com.google.android.gms.maps.MapFragment"      
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>



</RelativeLayout>

Mainfest 文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.dilip.googlemapsv2"
    android:versionCode="1"
    android:versionName="1.0" >
    <permission
        android:name="com.dilip.googlemapsv2.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="20" />
    <uses-permission android:name="com.dilip.googlemapsv2.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />



            <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=".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>

        <!-- Goolge API Key -->
        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="xxxxxxxxxxxxxxxxxxxxxxxxxxx" />                /* Added Bi Dilip */ 
        <meta-data 
            android:name="com.google.android.gms.version" 
            android:value="@integer/google_play_services_version" />
    </application>

</manifest>