地图类的 onCreate() 和 onMapReady() 函数从未运行

Question

我创建了一个基本的 Android 应用程序，该应用程序的目的是在其上放置一个带有汉堡抽屉的地图。每个汉堡菜单选项都会在 GoogleMap 对象上运行对象方法。

问题是，当汉堡抽屉被创建并工作时，地图的片段被放置在正确的位置，MainActivity 中的 onCreate 和随后的 onMapReady 函数没有运行，这意味着 GoogleMap 对象永远不会被创建。我在这些函数中添加了一些打印语句以确保它们永远不会被打印。

我有两个类，HamburgerDrawer.java 和 MainActivity.java。

HamburgerDrawer.java：

package com.vanleusen.brighthelp;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import com.google.android.gms.common.api.GoogleApiClient;

public class HamburgerDrawer extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
    //testing

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_hamburger_drawer);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);



    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    /*FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.add(R.id.frame_container, new MyFragment());
    transaction.commit();*/

    //MainActivity map = new MainActivity();

}



@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

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

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

    return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_roadmap) {
        System.out.println("Roadmap");
        //mapData.mapTypeInterface(1);
    } else if (id == R.id.nav_satellite) {
        System.out.println("Satellite");
        //mapData.mapTypeInterface(2);
    } else if (id == R.id.nav_hybrid) {
        System.out.println("Hybrid");
        //mapData.mapTypeInterface(3);
    } else if (id == R.id.nav_terrain) {
        System.out.println("Terrain");
        //mapData.mapTypeInterface(4);
    } else if (id == R.id.nav_problems) {
        System.out.println("Report Problems");
    } else if (id == R.id.nav_contact) {
        System.out.println("Contact Us");
    } else if (id == R.id.nav_about) {
        System.out.println("About");
    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

}

MainActivity.java：

package com.vanleusen.brighthelp;

/**
 * Created by Oscar on 22/10/2016.
 */
import android.app.Activity;
import android.os.Bundle;
import android.view.View;

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

public class MainActivity extends Activity implements OnMapReadyCallback {
    private GoogleMap mMap;
    public static MapFragment mapFragment;

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

        mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        System.out.println("Ran onCreate method");
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        System.out.println("Ran onMapReady method");
        mMap = googleMap;
        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-34, 151);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }
}

我有多个布局 xml 文件来实现汉堡菜单，虽然包含抽屉内容的相关文件在这里：

content_hamburger_drawer.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:id="@+id/content_hamburger_drawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.vanleusen.brighthelp.HamburgerDrawer"
    tools:showIn="@layout/app_bar_hamburger_drawer">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

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

        <view
            android:id="@+id/myview"
            android:layout_width="match_parent"
            android:layout_height="fill_parent"
            class="android.view.View" />
    </FrameLayout>

</RelativeLayout>

最后我听说这可能与我的 AndroidManifest 相关，尽管我尝试了一些更正，但似乎对我没有任何帮助，我将其包括在下面：

AndroidManifest.xml：

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

    <!--
         The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
         Google Maps Android API v2, but you must specify either coarse or fine
         location permissions for the 'MyLocation' functionality. 
    -->
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".HamburgerDrawer"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        launchMode ensures intents don't create multiple instances of it
        <activity
            android:name=".MainActivity"
            android:label="Map"
            android:theme="@style/AppTheme.NoActionBar"
            android:launchMode="singleTask" >
        </activity>


        <!--
             The API key for Google Maps-based APIs is defined as a string resource.
             (See the file "res/values/google_maps_api.xml").
             Note that the API key is linked to the encryption key used to sign the APK.
             You need a different API key for each encryption key, including the release key that is used to
             sign the APK for publishing.
             You can define the keys for the debug and release targets in src/debug/ and src/release/. 
        -->
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />
        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />

    </application>

</manifest>

如果有人能帮我弄清楚为什么我的地图的 onCreate 和 onMapReady 函数没有被执行，我将不胜感激。

Answer 1

我认为您没有从任何地方调用 MainActivity 类，这就是出现此问题的原因。请在 onCreate 方法或任何 clicklistener 中从 HamburgerDrawer 类调用它。

Intent a=new Intent(getApplicationContext,MainActivity.class);
startActivity(a);