Attribute für benutzerdefinierte Android-Kartenfragmente

Question

Ich versuche, einem Google Map-Fragment bei einer meiner Aktivitäten einen Marker hinzuzufügen. Die Karte wird angezeigt, aber es gibt keine Markierung. Es könnte etwas mit dem Aktivitätstyp zu tun haben. Quellcode unten.

content_checkin_info.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: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" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="com.example.martin.ivebeenthere.CheckinInfo" 
    tools:showIn="@layout/app_bar_checkin_info"> 

    <ImageView 
     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:id="@+id/imageView3" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:src="@drawable/craig"/> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceMedium" 
     android:text="" 
     android:id="@+id/textView7" 
     android:layout_alignParentTop="true" 
     android:layout_centerHorizontal="true" /> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceMedium" 
     android:text="" 
     android:id="@+id/textView8" 
     android:layout_below="@+id/textView7" 
     android:layout_alignLeft="@+id/textView7" 
     android:layout_alignStart="@+id/textView7" /> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="" 
     android:id="@+id/textView9" 
     android:layout_marginTop="30dp" 
     android:layout_below="@+id/fragment" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" /> 

    <fragment 
     android:layout_width="wrap_content" 
     android:layout_height="250dp" 
     android:name="com.google.android.gms.maps.MapFragment" 
     android:id="@+id/fragment" 
     android:layout_below="@+id/imageView3" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true" 
     android:layout_marginTop="31dp" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" /> 

</RelativeLayout> 

CheckinInfo.java

package com.example.martin.ivebeenthere; 

import android.content.Intent; 
import android.os.AsyncTask; 
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 android.widget.TextView; 
import android.widget.Toast; 


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

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.methods.HttpGet; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.protocol.BasicHttpContext; 
import org.apache.http.protocol.HttpContext; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.IOException; 
import java.io.InputStream; 

public class CheckinInfo extends AppCompatActivity 
     implements NavigationView.OnNavigationItemSelectedListener { 

    private TextView txtInfo; 
    private TextView txtUser; 
    private TextView txtVisit; 

    private SupportMapFragment mapFragment; 
    private GoogleMap mMap; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_checkin_info); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     new LongRunningGetIO().execute(); 

     mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.fragment)); 
     if (mapFragment != null) { 
      mapFragment.getMapAsync(new OnMapReadyCallback() { 
       @Override 
       public void onMapReady(GoogleMap googleMap) { 
        mMap = googleMap; 
        LatLng mayo = new LatLng(53.9345, -9.3516); 
        mMap.addMarker(new MarkerOptions().position(mayo).title("Jack White - Mayo")); 
       } 
      }); 
     } 

     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); 
    } 

    private class LongRunningGetIO extends AsyncTask<Void, Void, String> { 

     protected String getASCIIContentFromEntity(HttpEntity entity) throws IllegalStateException, IOException { 
      InputStream in = entity.getContent(); 
      StringBuffer out = new StringBuffer(); 
      int n = 1; 
      while (n > 0) { 
       byte[] b = new byte[4096]; 
       n = in.read(b); 
       if (n > 0) out.append(new String(b, 0, n)); 
      } 
      return out.toString(); 
     } 

     @Override 
     protected String doInBackground(Void... params) { 
      HttpClient httpClient = new DefaultHttpClient(); 
      HttpContext localContext = new BasicHttpContext(); 
      HttpGet httpGet = new HttpGet("https://api.myjson.com/bins/20xew"); 
      String text = null; 
      try { 
       HttpResponse response = httpClient.execute(httpGet, localContext); 
       HttpEntity entity = response.getEntity(); 
       text = getASCIIContentFromEntity(entity); 
      } catch (Exception e) { 
       return e.getLocalizedMessage(); 
      } 
      return text; 
     } 

     protected void onPostExecute(String results) { 
      if (results != null) { 

       JSONArray myJSONArray; 
       try { 
        myJSONArray = new JSONArray(results); 

        for (int i = 0; i < myJSONArray.length(); i++) { 
         JSONObject obj = (JSONObject) myJSONArray.get(i); 

         String info = obj.getString("Info"); 
         String user = obj.getString("User"); 
         String visit = obj.getString("Visit"); 
         txtInfo = (TextView) findViewById(R.id.textView9); 
         txtUser = (TextView) findViewById(R.id.textView7); 
         txtVisit = (TextView) findViewById(R.id.textView8); 
         txtInfo.setText(info); 
         txtUser.setText(user); 
         txtVisit.setText(visit); 
        } 
       } catch (JSONException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
       } 

      } 
     } 
    } 

    @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.checkin_info, menu); 
     return true; 
    } 

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

     if (id == R.id.nav_feed) { 
      startActivity(new Intent(getApplicationContext(), Feed.class)); 
     } else if (id == R.id.nav_map) { 
      startActivity(new Intent(getApplicationContext(), Map.class)); 
     } else if (id == R.id.nav_account) { 
      startActivity(new Intent(getApplicationContext(), Account.class)); 
     } else if (id == R.id.nav_logout) { 
      startActivity(new Intent(getApplicationContext(), Home.class)); 
      Toast.makeText(getApplicationContext(), "Logged Out", 
        Toast.LENGTH_LONG).show(); 
     } 

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

Answer 1

Da unten Code gibt null

mapFragment = ((SupportMapFragment) getSupportFragmentManager() 
    .findFragmentById(R.id.fragment)); 

Verwendenverwenden sollten Auchin xml

<fragment 
     android:layout_width="wrap_content" 
     android:layout_height="250dp" 
     android:name="com.google.android.gms.maps.SupportMapFragment" 
     android:id="@+id/fragment" 
     android:layout_below="@+id/imageView3" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true" 
     android:layout_marginTop="31dp" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" />