android - Google map 未显示在 ViewPager 中的选项卡 fragment 上

Question

我正在一个新的 Android 项目中工作。

第一个 Activity 是使用 slider 菜单和 fragment 。在第一个 fragment 上有一个 ListView (PrimaryFragmentDormir.java)。选择其中一行后，将启动一个新 Activity 。最后一个 Activity 使用三个选项卡来显示有关所选行对象的不同信息。 ListView 是从远程 JSON 文件加载的。第一个选项卡显示有关所选对象的详细信息，第二个选项卡应显示 map 。

我已经按照官方文档设置了所有需要的东西，以便在我的应用程序中包含 Google map ，至少我是这么认为的。当用户选择第二个选项卡时，将显示一个空白屏幕，并在左下角显示 Google Logo 。

这是 Android list :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.solinpromex.elpasojuarezexperience" >

    <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="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"/>

    <uses-library android:name="com.google.android.maps"/>


    <application
        android:name=".app.AppController"
        android:allowBackup="true"
        android:icon="@mipmap/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="..hidden here..." />
        <activity
            android:name=".Inicio"
            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=".MainActivity"
            android:label="@string/app_name" >
        </activity>
        <activity
            android:name=".Detalle_Hotel"
            android:label="@string/title_activity_detalle__hotel" >
        </activity>



    </application>

</manifest>

这里是托管选项卡的主要 Activity :

import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class Detalle_Hotel extends AppCompatActivity {
    // Declaring Your View and Variables

    public String nombre_hotel_recibido, foto_hotel_recibido, descripcion_hotel_recibido,direccion_hotel_recibido,web_hotel,tel_hotel,tel_reservas,zona_hotel,facebook_hotel,twitter_hotel;
    private int hotel_num_estrellas, id_hotel;
    private double calificacion_hotel,latitud_hotel,longitud_hotel;

    Toolbar toolbar;
    ViewPager pager;
    ViewPagerAdapter adapter;
    SlidingTabLayout tabs;
    CharSequence Titles[]={"Info","Mapa","Opinión"};
    int Numboftabs =3;

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

        nombre_hotel_recibido = getIntent().getStringExtra("nombre_hotel");
        direccion_hotel_recibido = getIntent().getStringExtra("direccion_hotel");
        descripcion_hotel_recibido = getIntent().getStringExtra("descripcion_hotel");
        foto_hotel_recibido = getIntent().getStringExtra("foto_hotel");
        hotel_num_estrellas = getIntent().getIntExtra("num_estrellas",0);
        setTitle(nombre_hotel_recibido);

        // Creating The Toolbar and setting it as the Toolbar for the activity

        toolbar = (Toolbar) findViewById(R.id.tool_bar);
        setSupportActionBar(toolbar);


        // Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
        adapter =  new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);

        // Assigning ViewPager View and setting the adapter
        pager = (ViewPager) findViewById(R.id.pager);
        pager.setAdapter(adapter);

        // Assiging the Sliding Tab Layout View
        tabs = (SlidingTabLayout) findViewById(R.id.tabs);
        tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width

        // Setting Custom Color for the Scroll bar indicator of the Tab View
        tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return getResources().getColor(R.color.rojomodesto);
            }
        });

        // Setting the ViewPager For the SlidingTabsLayout
        tabs.setViewPager(pager);



    }



}

这里是第二个选项卡的代码:

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.google.android.gms.maps.GoogleMap;

import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import com.google.android.gms.maps.GoogleMap;

import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;



public class Tab2 extends Fragment {

    private GoogleMap map;
    static final LatLng HAMBURG = new LatLng(53.558, 9.927);
    static final LatLng KIEL = new LatLng(53.551, 9.993);

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.tab_2, container, false);

        return v;


    }


    @Override
    public void onActivityCreated(Bundle state) {
        super.onActivityCreated(state);


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

        if (map!=null){
            Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
                    .title("Hamburg"));
            Marker kiel = map.addMarker(new MarkerOptions()
                    .position(KIEL)
                    .title("Kiel")
                    .snippet("Kiel is cool")
                    .icon(BitmapDescriptorFactory
                            .fromResource(R.drawable.res)));
        }

    }

}

我已经检查了 API key ，没有问题。感谢您的支持。

Answer 1

问题是，当您调用 getActivity().getFragmentManager() 时，您将获得 Activity 的 fragment 管理器。

由于您在 Fragment 中使用了嵌套的 MapFragment，因此您需要使用 getChildFragmentManager():例如:

GoogleMap mapFragment = ((MapFragment) getChildFragmentManager()
            .findFragmentById(R.id.map)).getMap();

所以，替换这个:

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

有了这个:

map = ((MapFragment) getChildFragmentManager().findFragmentById(R.id.map))
                .getMap();

但是，虽然这可行，但您最好让 Fragment 扩展 MapFragment 或 SupportMapFragment，这样您就不需要嵌套 Fragment，并且可以避免遇到 this problem 的可能性.

使用支持库中的 TabLayout 的解决方案:

由于 ActionBar 选项卡已弃用，现在这是使用 ViewPager 实现选项卡的最佳方式。请注意，这是在不使用嵌套 SupportMapFragment 的情况下完成的，而是使用 map fragment 范围 SupportMapFragment:

MainActivity 导入:

import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v4.app.FragmentManager;
import android.view.View;
import android.widget.TextView;

MainActivity 类:

public class MainActivity extends AppCompatActivity {

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        // Get the ViewPager and set it's PagerAdapter so that it can display items
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        PagerAdapter pagerAdapter =
                new PagerAdapter(getSupportFragmentManager(), MainActivity.this);
        viewPager.setAdapter(pagerAdapter);

        // Give the TabLayout the ViewPager
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.setupWithViewPager(viewPager);

        // Iterate over all tabs and set the custom view
        for (int i = 0; i < tabLayout.getTabCount(); i++) {
            TabLayout.Tab tab = tabLayout.getTabAt(i);
            tab.setCustomView(pagerAdapter.getTabView(i));
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    class PagerAdapter extends FragmentPagerAdapter {

        String tabTitles[] = new String[] { "Tab One", "Tab Two", "Tab Three", };
        Context context;

        public PagerAdapter(FragmentManager fm, Context context) {
            super(fm);
            this.context = context;
        }

        @Override
        public int getCount() {
            return tabTitles.length;
        }

        @Override
        public Fragment getItem(int position) {

            switch (position) {
                case 0:
                    return new BlankFragment();
                case 1:
                    return new BlankFragment();
                case 2:
                    return new MapFragment();
            }

            return null;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            // Generate title based on item position
            return tabTitles[position];
        }

        public View getTabView(int position) {
            View tab = LayoutInflater.from(MainActivity.this).inflate(R.layout.custom_tab, null);
            TextView tv = (TextView) tab.findViewById(R.id.custom_text);
            tv.setText(tabTitles[position]);
            return tab;
        }

    }
}

MapFragment，请注意它直接扩展了 SupportMapFragment 而不是在其中嵌套了 SupportMapFragment:

import android.util.Log;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
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.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapFragment extends SupportMapFragment implements
        OnMapReadyCallback {

    private final LatLng HAMBURG = new LatLng(53.558, 9.927);
    private final LatLng KIEL = new LatLng(53.551, 9.993);

    private static final String ARG_SECTION_NUMBER = "section_number";

    private GoogleMap mMap;
    private Marker marker;

    public MapFragment() {
    }

    @Override
    public void onResume() {
        super.onResume();

        Log.d("MyMap", "onResume");
        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {

        if (mMap == null) {

            Log.d("MyMap", "setUpMapIfNeeded");

            getMapAsync(this);
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        Log.d("MyMap", "onMapReady");
        mMap = googleMap;
        setUpMap();
    }

    private void setUpMap() {

        mMap.setMyLocationEnabled(true);
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        mMap.getUiSettings().setMapToolbarEnabled(false);


        mMap.setMyLocationEnabled(true);
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        mMap.getUiSettings().setMapToolbarEnabled(false);

        Marker hamburg = mMap.addMarker(new MarkerOptions().position(HAMBURG)
                .title("Hamburg"));
        Marker kiel = mMap.addMarker(new MarkerOptions()
                .position(KIEL)
                .title("Kiel")
                .snippet("Kiel is cool")
                .icon(BitmapDescriptorFactory
                        .fromResource(R.mipmap.ic_launcher)));

        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));

        mMap.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
    }
}

Activity 的布局 xml:

<RelativeLayout
    android:id="@+id/main_layout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:background="?attr/colorPrimary"
        android:elevation="6dp"
        android:minHeight="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

    <android.support.design.widget.TabLayout
        android:id="@+id/tab_layout"
        app:tabMode="fixed"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/toolbar"
        android:background="?attr/colorPrimary"
        android:elevation="6dp"
        app:tabTextColor="#d3d3d3"
        app:tabSelectedTextColor="#ffffff"
        app:tabIndicatorColor="#ff00ff"
        android:minHeight="?attr/actionBarSize"
        />

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_below="@id/tab_layout"/>

</RelativeLayout>

custom_tab.xml，这是每个选项卡的布局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/custom_text"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:background="?attr/selectableItemBackground"
        android:gravity="center"
        android:textSize="16dip"
        android:textColor="#ffffff"
        android:singleLine="true"
        />
</LinearLayout>

Gradle :

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:design:23.0.1'
    compile 'com.google.android.gms:play-services:7.0.0'
}

结果: