Android导航抽屉Google地图片段错误我该如何解决它？

我该如何解决这个问题？Android导航抽屉Google地图片段错误我该如何解决它？

GmapFragment.java

这条线我收到提示

fragment.getMapAsync（本）

显示java.lang.NullPointerException

我重视的logcat

我已编辑该代码2天

找不到解决方案。

我的源代码是当用户点击导航抽屉时运行谷歌地图。

当我点击抽屉菜单。

我得到错误显示java.lang.NullPointerException

MainActivity.java

package youtube.demo.youtubedemo; 

import android.app.FragmentManager; 
import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.view.View; 
import android.support.design.widget.NavigationView; 
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 com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.OnMapReadyCallback; 
import com.google.android.gms.maps.SupportMapFragment; 

import youtube.demo.youtubedemo.Fragments.GmapFragment; 
import youtube.demo.youtubedemo.Fragments.ImportFragment; 
import youtube.demo.youtubedemo.Fragments.MainFragment; 

public class MainActivity extends AppCompatActivity 
    implements NavigationView.OnNavigationItemSelectedListener { 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     setContentView(R.layout.activity_main); 
     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); 

     FragmentManager fm = getFragmentManager(); 
     fm.beginTransaction().replace(R.id.content_frame, new MainFragment()).commit(); 

} 

    @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.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(); 

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

     return super.onOptionsItemSelected(item); 
    } 

    @SuppressWarnings("StatementWithEmptyBody") 
    @Override 
     public boolean onNavigationItemSelected(MenuItem item) { 
     FragmentManager fm = getFragmentManager(); 

     int id = item.getItemId(); 

     if (id == R.id.nav_camara) { 
      fm.beginTransaction().replace(R.id.content_frame, new ImportFragment()).commit(); 
     } else if (id == R.id.nav_gallery) { 
      fm.beginTransaction().replace(R.id.content_frame, new GmapFragment()).commit(); 
     } else if (id == R.id.nav_slideshow) { 

     } else if (id == R.id.nav_manage) { 

     } else if (id == R.id.nav_share) { 

     } else if (id == R.id.nav_send) { 

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

    }

MainFragment.java

package youtube.demo.youtubedemo.Fragments; 

import android.app.Fragment; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

import youtube.demo.youtubedemo.R; 

public class MainFragment extends Fragment { 

     @Nullable 
     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
      return inflater.inflate(R.layout.fragment_main,container,false); 
     } 
    }

ImportFragment.java

package youtube.demo.youtubedemo.Fragments; 

import android.app.Fragment; 
import android.content.Context; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 


import youtube.demo.youtubedemo.R; 

public class ImportFragment extends Fragment { 

     @Nullable 
     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
      return inflater.inflate(R.layout.fragment_import, container,false); 
    } 

     @Override 
     public void onViewCreated(View view, Bundle savedInstanceState) { 
      super.onViewCreated(view, savedInstanceState); 
    } 

}

GMAP Fragment.java

package youtube.demo.youtubedemo.Fragments; 

import android.app.Fragment; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.support.v4.app.FragmentActivity; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

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

import youtube.demo.youtubedemo.R; 

public class GmapFragment extends Fragment implements OnMapReadyCallback { 


     @Nullable 
     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container,  Bundle savedInstanceState) { 
      return inflater.inflate(R.layout.fragment_gmaps, container,false); 
    } 

     @Override 
     public void onViewCreated(View view, Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 

     MapFragment fragment = (MapFragment)this.getChildFragmentManager().findFragmentById(R.id.map); 
     fragment.getMapAsync(this); 
} 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 

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

     googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(marker, 13)); 

     googleMap.addMarker(new MarkerOptions().title("Hello Google Maps!").position(marker)); 
    } 
}

fragment_main.xml

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

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceMedium" 
     android:text="Main Fragment" 
     android:id="@+id/textView2" 
     android:layout_gravity="center" /> 
</FrameLayout>

fragment_import.xml

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

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceMedium" 
     android:text="Import Fragment" 
     android:id="@+id/textView2" 
     android:layout_gravity="center" /> 
</FrameLayout>

fragment_gmaps.xml

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

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

</FrameLayout> 







08-25 09:38:01.621 22053-22053/youtube.demo.youtubedemo E/AndroidRuntime: FATAL EXCEPTION: main 
                     Process: youtube.demo.youtubedemo, PID: 22053 
                     java.lang.NullPointerException 
                      at youtube.demo.youtubedemo.Fragments.GmapFragment.onViewCreated(GmapFragment.java:35) 
                      at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:904) 
                      at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062) 
                      at android.app.BackStackRecord.run(BackStackRecord.java:684) 
                      at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1453) 
                      at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443) 
                      at android.os.Handler.handleCallback(Handler.java:733) 
                      at android.os.Handler.dispatchMessage(Handler.java:95) 
                      at android.os.Looper.loop(Looper.java:146) 
                      at android.app.ActivityThread.main(ActivityThread.java:5602) 
                      at java.lang.reflect.Method.invokeNative(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:515) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
                      at dalvik.system.NativeStart.main(Native Method) 
08-25 09:38:03.596 22053-22161/youtube.demo.youtubedemo W/DynamiteModule: Local module descriptor class for com.google.android.gms.googlecertificates not found. 
08-25 09:38:03.601 22053-22161/youtube.demo.youtubedemo I/DynamiteModule: Considering local module com.google.android.gms.googlecertificates:0 and remote module com.google.android.gms.googlecertificates:1 
08-25 09:38:03.601 22053-22161/youtube.demo.youtubedemo I/DynamiteModule: Selected remote version of com.google.android.gms.googlecertificates, version >= 1 
08-25 09:38:03.601 22053-22161/youtube.demo.youtubedemo D/ChimeraFileApk: Primary ABI of requesting process is armeabi-v7a 
08-25 09:38:03.601 22053-22161/youtube.demo.youtubedemo D/ChimeraFileApk: Classloading successful. Optimized code found. 
08-25 09:38:03.606 22053-22161/youtube.demo.youtubedemo D/GoogleCertificates: com.google.android.gms.googlecertificates module is loaded 
08-25 09:38:03.636 22053-22161/youtube.demo.youtubedemo D/GoogleCertificatesImpl: Fetched 163 Google release certificates 
08-25 09:38:03.666 22053-22161/youtube.demo.youtubedemo D/GoogleCertificatesImpl: Fetched 318 Google certificates

来源

2016-08-25 user3662974

，请接受我的答案如果它解决您的问题 –

对不起米娜福吉。我应该在哪里点击？我点了upvote。我应该在哪里点击才能让它回答？ – user3662974

有一步，你必须确保你做开始接收地图，就像变得有效谷歌地图API密钥流这tutorial。

根据你的代码，你需要移动到onCreateView

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View mView = inflater.inflate(R.layout.fragment_gmaps, container, false); 
    MapFragment fragment = (MapFragment)this.getChildFragmentManager().findFragmentById‌‌(R.id.map); 
    fragment.getMapAsync(this); 
    return mView ;

希望这有助于

来源

2016-08-25 10:36:47

抱歉Mina Fawzy。 MapFragment fragment =（MapFragment）this.getChildFragmentManager（）。findFragmentById（R.id.map）; fragment.getMapAsync（this）; 将此代码移至onCreateView？我转移到onCreateView上面的代码。它没有发生。你能举个例子吗？ – user3662974

和我正在使用认证谷歌地图API密钥。也注册了项目名称。 – user3662974

告诉我怎么看起来像里面oncreateview –

Android导航抽屉Google地图片段错误我该如何解决它？

回答

相关问题