getSupportFragmentManager返回nullgetSupportFragmentManager、null

2023-09-04 03:11:35 作者:你列表最软的妹

我想显示谷歌地图在我的Andr​​oid应用程序:

 公共类DisplayMapActivity扩展ActionBarActivity {
    私人LbsTracker2 lbsTracker2;
    私人GoogleMap的GoogleMap的;

    @覆盖
    保护无效的onCreate(包savedInstanceState){
        super.onCreate(savedInstanceState);
        的setContentView(R.layout.activity_main);

        尝试 {
            this.initilizeMap();

        }赶上(例外五){
            e.printStackTrace();
        }
    }

    @覆盖
    保护无效onResume(){
        super.onResume();
        initilizeMap();
    }

    私人无效initilizeMap(){
        如果(GoogleMap的== NULL){
            MapFragment mapFragment =(MapFragment)getFragmentManager()findFragmentById(R.id.map)。 //< ---总是空! :(
            GoogleMap的= mapFragment.getMap();
        }
    }
    ...
}
 

但我的变量mapFragment永远是我的方法initializeMap()

里面空

我的活动XML:

 < RelativeLayout的的xmlns:机器人=htt​​p://schemas.android.com/apk/res/android
    的xmlns:工具=htt​​p://schemas.android.com/tool​​s
    机器人:layout_width =match_parent
    机器人:layout_height =match_parent
    机器人:paddingBottom会=@扪/ activity_vertical_margin
    机器人:以下属性来=@扪/ activity_horizo​​ntal_margin
    机器人:paddingRight =@扪/ activity_horizo​​ntal_margin
    机器人:paddingTop =@扪/ activity_vertical_margin
    工具:上下文=com.example.lbsapp.DisplayMapActivity $ PlaceholderFragment>

    <片段
            机器人:ID =@ + ID /图
            机器人:名称=com.google.android.gms.maps.MapFragment
            机器人:layout_width =match_parent
            机器人:layout_height =match_parent
            机器人:标签=tag_fragment_map/>

< / RelativeLayout的>
 

我的应用程序的清单:

 < XML版本=1.0编码=UTF-8&GT?;
<舱单的xmlns:机器人=htt​​p://schemas.android.com/apk/res/android
    包=com.example.lbsapp
    安卓版code =1
    机器人:VERSIONNAME =1.0>

    <许可
        机器人:名称=info.androidhive.googlemapsv2.permission.MAPS_RECEIVE
        安卓的ProtectionLevel =签名/>

    <使用-权限的Andr​​oid:名称=info.androidhive.googlemapsv2.permission.MAPS_RECEIVE/>

    <用途-SDK
        安卓的minSdkVersion =14
        机器人:targetSdkVersion =19/>

    <使用-权限的Andr​​oid:名称=android.permission.ACCESS_NETWORK_STATE/>
    <使用-权限的Andr​​oid:名称=android.permission.INTERNET对/>
    <使用-权限的Andr​​oid:名称=com.google.android.providers.gsf.permission.READ_GSERVICES/>
    <使用-权限的Andr​​oid:名称=android.permission.WRITE_EXTERNAL_STORAG​​E/>

    <! - 必须出示当前位置 - >
    <使用-权限的Andr​​oid:名称=android.permission.ACCESS_COARSE_LOCATION/>
    <使用-权限的Andr​​oid:名称=android.permission.ACCESS_FINE_LOCATION/>

    <! - 必需的OpenGL ES 2.0。对于地图V2  - >
    <用途特征
        机器人:glEsVersion =0x00020000
        机器人:要求=真/>

    <应用
        机器人:allowBackup =真
        机器人:图标=@可绘制/ ic_launcher
        机器人:标签=@字符串/ APP_NAME
        机器人:主题=@风格/ AppTheme>
        <活动
            机器人:名称=com.example.lbsapp.MainActivity
            机器人:标签=@字符串/ APP_NAME>
            <意向滤光器>
                <作用机器人:名称=android.intent.action.MAIN/>

                <类机器人:名称=android.intent.category.LAUNCHER/>
            &所述; /意图滤光器>
        < /活性GT;
        <活动
            机器人:名称=com.example.lbsapp.DisplayLbsActivity
            机器人:标签=@字符串/ title_activity_display_lbs
            机器人:parentActivityName =com.example.lbsapp.MainActivity>
            &所述;元数据
                机器人:名称=android.support.PARENT_ACTIVITY
                机器人:值=com.example.lbsapp.MainActivity/>
        < /活性GT;

        <! -  Google网上地图API密钥 - >
        &所述;元数据
            机器人:名称=com.google.android.maps.v2.API_KEY
            机器人:值=AIzaSyDnnWGwO8Zfbn5PGKXPF3aspbZTCtJ6j7I/>

        <活动
            机器人:名称=com.example.lbsapp.DisplayMapActivity
            机器人:标签=@字符串/ title_activity_display_map
            机器人:parentActivityName =com.example.lbsapp.MainActivity>
            &所述;元数据
                机器人:名称=android.support.PARENT_ACTIVITY
                机器人:值=com.example.lbsapp.MainActivity/>
        < /活性GT;
    < /用途>

< /舱单>
 
android findviewbyid 返回null

解决方案

但问题是有:

 的setContentView(R.layout.activity_main);
 

当然,它必须是

 的setContentView(R.layout.activity_display_map);
 

I'd like to show Google maps in my android app:

public class DisplayMapActivity extends ActionBarActivity {
    private LbsTracker2 lbsTracker2;
    private GoogleMap googleMap;

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

        try {
            this.initilizeMap();

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

    @Override
    protected void onResume() {
        super.onResume();
        initilizeMap();
    }

    private void initilizeMap() {
        if (googleMap == null) {
            MapFragment mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.map); // <--- always null! :(
            googleMap = mapFragment.getMap();
        }
    }
    ...
}

But my variable mapFragment is always null inside my method initializeMap() ...

Xml of my activity:

<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.example.lbsapp.DisplayMapActivity$PlaceholderFragment" >

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

</RelativeLayout>

Manifest of my app:

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

    <permission
        android:name="info.androidhive.googlemapsv2.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-permission android:name="info.androidhive.googlemapsv2.permission.MAPS_RECEIVE" />

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

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <!-- Required to show current location --> 
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <!-- Required OpenGL ES 2.0. for Maps V2 -->
    <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.lbsapp.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>
        <activity
            android:name="com.example.lbsapp.DisplayLbsActivity"
            android:label="@string/title_activity_display_lbs"
            android:parentActivityName="com.example.lbsapp.MainActivity" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.lbsapp.MainActivity" />
        </activity>

        <!-- Goolge Maps API Key -->
        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="AIzaSyDnnWGwO8Zfbn5PGKXPF3aspbZTCtJ6j7I" />

        <activity
            android:name="com.example.lbsapp.DisplayMapActivity"
            android:label="@string/title_activity_display_map"
            android:parentActivityName="com.example.lbsapp.MainActivity" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.lbsapp.MainActivity" />
        </activity>
    </application>    

</manifest>

解决方案

The problem was there:

setContentView(R.layout.activity_main);

Of course it has to be

setContentView(R.layout.activity_display_map);