Android Google Maps v2从JSON数组添加地图标记php mySQL

我试图创建一个Android应用程序，它可以从我的mySQL数据库中在Google Maps v2上绘制标记，但它不起作用。Android Google Maps v2从JSON数组添加地图标记php mySQL

Mapactivity.java

public class MapsActivity extends FragmentActivity { 
    // Creating JSON Parser object 
    JSONParser jParser = new JSONParser(); 
    // url to get all products list 
    private static String url_all_products = "http://127.0.0.1/get_marker.php"; 
    // JSON Node names 
    private static final String TAG_SUCCESS = "success"; 
    private static final String TAG_Coordinates = "products"; 
    private static final String TAG_PID = "pid"; 
    private static final String TAG_X = "x_coordinate"; 
    private static final String TAG_Y = "y_coordinate"; 
    // products JSONArray 
    JSONArray products = null; 
    private GoogleMap mMap; // Might be null if Google Play services APK is not available. 

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

     setUpMapIfNeeded(); 
    } 

    @Override 
    protected void onResume() { 
     super.onResume(); 
     setUpMapIfNeeded(); 
    } 
    private void setUpMapIfNeeded() { 
     // Do a null check to confirm that we have not already instantiated the map. 
     if (mMap == null) { 
      // Try to obtain the map from the SupportMapFragment. 

      mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)) 
        .getMap(); 
      // Check if we were successful in obtaining the map. 
      if (mMap != null) { 



       // Add marker info window click listener 
       // mMap.setOnInfoWindowClickListener(this); 
       //Zooming Buttons 
       UiSettings mapSettings; 
       mapSettings = mMap.getUiSettings(); 
       mapSettings.setZoomControlsEnabled(true); 
       //Zooming Buttons 


       GetMarker(); 
      } 
     } 
    } 
    private void GetMarker() 
    { 
     mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN); 
     mMap.setMyLocationEnabled(true); 
     double xi = 49.999065; 
     double yi = 8.273978; 

     LatLng MUSEUM = new LatLng(xi , yi); 
     Marker museum = mMap.addMarker(new MarkerOptions() 
       .position(MUSEUM) 
       .title("Mainzer Dom") 
       .snippet("Der Mainzer Dom")); 


     new Thread(new Runnable() { 
      public void run() { 
       retrieveAndAddCities(); 
      } 
     }).start(); 

    } 

    private void retrieveAndAddCities() { 

     List params = new ArrayList(); 
     // getting JSON string from URL 
     JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params); 

     // Check your log cat for JSON reponse 
     Log.d("All Products: ", json.toString()); 

     try { 
      // Checking for SUCCESS TAG 
      int success = json.getInt(TAG_SUCCESS); 

      if (success == 1) { 
       // products found 
       // Getting Array of Products 
       products = json.getJSONArray(TAG_Coordinates); 

       // looping through All Products 
       for (int i = 0; i < products.length(); i++) { 
        JSONObject c = products.getJSONObject(i); 

        // Storing each json item in variable 
        int id = c.getInt(TAG_PID); 
        double x_coordinate = c.getDouble(TAG_X); 
        double y_coordinate = c.getDouble(TAG_Y); 
        mMap.addMarker(new MarkerOptions() 
          .position(new LatLng(x_coordinate,y_coordinate))); 
       } 

      } else { 


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

}

而且我的PHP代码： get_marker.php

<?php 

/* 
* Following code will list all the products 
*/ 


$response = array(); 


require_once __DIR__ . '/db_connect.php'; 


$db = new DB_CONNECT(); 


$result = mysql_query("SELECT *FROM products") or die(mysql_error()); 


if (mysql_num_rows($result) > 0) { 

    $response["products"] = array(); 

    while ($row = mysql_fetch_array($result)) { 

     $product = array(); 
     $product["pid"] = $row["pid"]; 
     $product["x_coordinate"] = $row["x_coordinate"]; 
     $product["y_coordinate"] = $row["y_coordinate"]; 
     $product["created_at"] = $row["created_at"]; 
     $product["updated_at"] = $row["updated_at"]; 


     array_push($response["products"], $product); 
    } 

    $response["success"] = 1; 

    // echoing JSON response 
    echo json_encode($response); 
} else { 

    $response["success"] = 0; 
    $response["message"] = "No products found"; 


    echo json_encode($response); 
} 
?>

，这是JsonParser

public class JSONParser { 

    static InputStream is = null; 
    static JSONObject jObj = null; 
    static String json = ""; 

    // constructor 
    public JSONParser() { 

    } 

    // function get json from url 
    // by making HTTP POST or GET mehtod 
    public JSONObject makeHttpRequest(String url, String method, 
             List<NameValuePair> params) { 

     // Making HTTP request 
     try { 

      // check for request method 
      if(method == "POST"){ 
       // request method is POST 
       // defaultHttpClient 
       DefaultHttpClient httpClient = new DefaultHttpClient(); 
       HttpPost httpPost = new HttpPost(url); 
       httpPost.setEntity(new UrlEncodedFormEntity(params)); 

       HttpResponse httpResponse = httpClient.execute(httpPost); 
       HttpEntity httpEntity = httpResponse.getEntity(); 
       is = httpEntity.getContent(); 

      }else if(method == "GET"){ 
       // request method is GET 
       DefaultHttpClient httpClient = new DefaultHttpClient(); 
       String paramString = URLEncodedUtils.format(params, "utf-8"); 
       url += "?" + paramString; 
       HttpGet httpGet = new HttpGet(url); 

       HttpResponse httpResponse = httpClient.execute(httpGet); 
       HttpEntity httpEntity = httpResponse.getEntity(); 
       is = httpEntity.getContent(); 
      } 

     } catch (UnsupportedEncodingException e) { 
      e.printStackTrace(); 
     } catch (ClientProtocolException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 

     try { 
      BufferedReader reader = new BufferedReader(new InputStreamReader(
        is, "iso-8859-1"), 8); 
      StringBuilder sb = new StringBuilder(); 
      String line = null; 
      while ((line = reader.readLine()) != null) { 
       sb.append(line + "\n"); 
      } 
      is.close(); 
      json = sb.toString(); 
     } catch (Exception e) { 
      Log.e("Buffer Error", "Error converting result " + e.toString()); 
     } 

     // try parse the string to a JSON object 
     try { 
      jObj = new JSONObject(json); 
     } catch (JSONException e) { 
      Log.e("JSON Parser", "Error parsing data " + e.toString()); 
     } 

     // return JSON String 
     return jObj; 

    } 
}

如果我尝试启动retrieveAndAddCities（）;

new Thread(new Runnable() { 
      public void run() { 
       retrieveAndAddCities(); 
      } 
     }).start();

我的应用程序会崩溃。

我希望有人能帮助我。非常感谢

编辑： logcat的：

04-06 01:50:04.268 5153-5168/flo.myapplication D/OpenGLRenderer﹕ Render dirty regions requested: true 
04-06 01:50:04.271 5153-5153/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0xae0d8560, tid 5153 
04-06 01:50:04.304 5153-5153/flo.myapplication D/Atlas﹕ Validating map... 
04-06 01:50:04.364 5153-5168/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0xae0d8ae0, tid 5168 
04-06 01:50:04.373 5153-5168/flo.myapplication I/OpenGLRenderer﹕ Initialized EGL, version 1.4 
04-06 01:50:04.446 5153-5168/flo.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0 
04-06 01:50:04.465 5153-5168/flo.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
04-06 01:50:04.465 5153-5168/flo.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa605e2c0, error=EGL_SUCCESS 
04-06 01:50:11.068 5153-5153/flo.myapplication I/zzx﹕ Making Creator dynamically 
04-06 01:50:11.071 5153-5153/flo.myapplication W/ResourcesManager﹕ Asset path '/system/framework/com.android.media.remotedisplay.jar' does not exist or contains no resources. 
04-06 01:50:11.071 5153-5153/flo.myapplication W/ResourcesManager﹕ Asset path '/system/framework/com.android.location.provider.jar' does not exist or contains no resources. 
04-06 01:50:11.088 5153-5153/flo.myapplication I/Google Maps Android API﹕ Google Play services client version: 7095000 
04-06 01:50:11.092 5153-5153/flo.myapplication I/Google Maps Android API﹕ Google Play services package version: 7097470 
04-06 01:50:11.205 5153-5165/flo.myapplication I/art﹕ Background partial concurrent mark sweep GC freed 11075(592KB) AllocSpace objects, 0(0B) LOS objects, 38% free, 6MB/10MB, paused 5.446ms total 25.641ms 
04-06 01:50:11.363 5153-5165/flo.myapplication I/art﹕ Background sticky concurrent mark sweep GC freed 49928(2039KB) AllocSpace objects, 3(561KB) LOS objects, 0% free, 11MB/11MB, paused 2.593ms total 119.732ms 
04-06 01:50:11.423 5153-5165/flo.myapplication I/art﹕ Background partial concurrent mark sweep GC freed 12702(547KB) AllocSpace objects, 2(1015KB) LOS objects, 28% free, 10MB/14MB, paused 5.173ms total 52.148ms 
04-06 01:50:11.551 5153-5153/flo.myapplication I/Choreographer﹕ Skipped 31 frames! The application may be doing too much work on its main thread. 
04-06 01:50:11.608 5153-5168/flo.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
04-06 01:50:11.608 5153-5168/flo.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa602e720, error=EGL_SUCCESS 
04-06 01:50:11.648 5153-5185/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0xa5491d90, tid 5185 
04-06 01:50:11.657 5153-5186/flo.myapplication D/All Products:﹕ {"products":[{"pid":"1","x_coordinate":"50","y_coordinate":"8","created_at":"2015-04-06 01:13:22","updated_at":"0000-00-00 00:00:00"}],"success":1} 
04-06 01:50:11.657 5153-5186/flo.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: Thread-378 
    Process: flo.myapplication, PID: 5153 
    java.lang.IllegalStateException: Not on the main thread 
      at com.google.l.a.cd.b(Unknown Source) 
      at com.google.maps.api.android.lib6.c.ca.a(Unknown Source) 
      at com.google.maps.api.android.lib6.c.el.a(Unknown Source) 
      at com.google.android.gms.maps.internal.l.onTransact(SourceFile:167) 
      at android.os.Binder.transact(Binder.java:380) 
      at com.google.android.gms.maps.internal.IGoogleMapDelegate$zza$zza.addMarker(Unknown Source) 
      at com.google.android.gms.maps.GoogleMap.addMarker(Unknown Source) 
      at flo.myapplication.MapsActivity.retrieveAndAddCities(MapsActivity.java:201) 
      at flo.myapplication.MapsActivity.access$000(MapsActivity.java:98) 
      at flo.myapplication.MapsActivity$1.run(MapsActivity.java:168) 
      at java.lang.Thread.run(Thread.java:818)

好吧，我修改了代码的AsyncTask现在，但我得到的错误太

package flo.myapplication; 

import android.os.StrictMode; 
import android.support.v4.app.FragmentActivity; 
import android.os.Bundle; 

import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.SupportMapFragment; 
import com.google.android.gms.maps.model.LatLng; 
import com.google.android.gms.maps.model.Marker; 
import com.google.android.gms.maps.model.MarkerOptions; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.util.Log; 
import android.view.View; 
import android.app.Activity; 
import android.app.Dialog; 
import android.app.ProgressDialog; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.content.SharedPreferences; 
import android.content.res.Resources; 
import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Typeface; 
import android.graphics.drawable.Drawable; 
import android.location.Location; 
import android.location.LocationManager; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.v7.app.ActionBarActivity; 
import android.util.DisplayMetrics; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.ViewGroup.LayoutParams; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.RelativeLayout; 
import android.widget.TextView; 

import com.google.android.gms.maps.UiSettings; 
import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.maps.CameraUpdate; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.GoogleMap.OnMarkerClickListener; 
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; 

import org.apache.http.NameValuePair; 
import org.apache.http.message.BasicNameValuePair; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
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; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import android.app.Dialog; 
import android.location.Criteria; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.util.Log; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.HttpURLConnection; 
import java.net.URL; 
import java.util.ArrayList; 
import java.util.List; 

public class MapsActivity extends FragmentActivity { 
    // Creating JSON Parser object 
    JSONParser jParser = new JSONParser(); 
    // url to get all products list 
    private static String url_all_products = "http://88.198.46.8/get_marker.php"; 
    // JSON Node names 
    private static final String TAG_SUCCESS = "success"; 
    private static final String TAG_Coordinates = "products"; 
    private static final String TAG_PID = "pid"; 
    private static final String TAG_X = "x_coordinate"; 
    private static final String TAG_Y = "y_coordinate"; 
    // products JSONArray 
    JSONArray products = null; 
    private GoogleMap mMap; // Might be null if Google Play services APK is not available. 

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

     setUpMapIfNeeded(); 
    } 

    @Override 
    protected void onResume() { 
     super.onResume(); 
     setUpMapIfNeeded(); 
    } 
    private void setUpMapIfNeeded() { 
     // Do a null check to confirm that we have not already instantiated the map. 
     if (mMap == null) { 
      // Try to obtain the map from the SupportMapFragment. 

      mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)) 
        .getMap(); 
      // Check if we were successful in obtaining the map. 
      if (mMap != null) { 



       // Add marker info window click listener 
       // mMap.setOnInfoWindowClickListener(this); 
       //Zooming Buttons 
       UiSettings mapSettings; 
       mapSettings = mMap.getUiSettings(); 
       mapSettings.setZoomControlsEnabled(true); 
       //Zooming Buttons 


       GetMarker(); 
      } 
     } 
    } 
    private void GetMarker() 
    { 
     mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN); 
     mMap.setMyLocationEnabled(true); 
     double xi = 49.999065; 
     double yi = 8.273978; 

     LatLng MUSEUM = new LatLng(xi , yi); 
     Marker museum = mMap.addMarker(new MarkerOptions() 
       .position(MUSEUM) 
       .title("Mainzer Dom") 
       .snippet("Der Mainzer Dom")); 


     // Loading products in Background Thread 
     new retrieveAndAddCities().execute(); 





    } 

    class retrieveAndAddCities extends AsyncTask<String, String, String> { 
     protected String doInBackground(String... args) { 
      List params = new ArrayList(); 
      // getting JSON string from URL 
      JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params); 

      // Check your log cat for JSON reponse 
      Log.d("All Products: ", json.toString()); 

      try { 
       // Checking for SUCCESS TAG 
       int success = json.getInt(TAG_SUCCESS); 

       if (success == 1) { 
        // products found 
        // Getting Array of Products 
        products = json.getJSONArray(TAG_Coordinates); 

        // looping through All Products 
        for (int i = 0; i < products.length(); i++) { 
         JSONObject c = products.getJSONObject(i); 

         // Storing each json item in variable 
         int id = c.getInt(TAG_PID); 
         double x_coordinate = c.getDouble(TAG_X); 
         double y_coordinate = c.getDouble(TAG_Y); 
         mMap.addMarker(new MarkerOptions() 
           .position(new LatLng(x_coordinate,y_coordinate))); 
        } 

       } else { 


       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 
      return null; 
     } 

    } 



}

和logcat的文件：

04-06 02:29:30.055 5324-5339/flo.myapplication D/OpenGLRenderer﹕ Render dirty regions requested: true 
04-06 02:29:30.076 5324-5324/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0xae0d5550, tid 5324 
04-06 02:29:30.129 5324-5324/flo.myapplication D/Atlas﹕ Validating map... 
04-06 02:29:30.274 5324-5339/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0xae0d59a0, tid 5339 
04-06 02:29:30.397 5324-5339/flo.myapplication I/OpenGLRenderer﹕ Initialized EGL, version 1.4 
04-06 02:29:30.574 5324-5339/flo.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0 
04-06 02:29:30.693 5324-5339/flo.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
04-06 02:29:30.693 5324-5339/flo.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa604a400, error=EGL_SUCCESS 
04-06 02:29:30.788 5324-5324/flo.myapplication I/Choreographer﹕ Skipped 37 frames! The application may be doing too much work on its main thread. 
04-06 02:29:37.319 5324-5324/flo.myapplication I/zzx﹕ Making Creator dynamically 
04-06 02:29:37.321 5324-5324/flo.myapplication W/ResourcesManager﹕ Asset path '/system/framework/com.android.media.remotedisplay.jar' does not exist or contains no resources. 
04-06 02:29:37.321 5324-5324/flo.myapplication W/ResourcesManager﹕ Asset path '/system/framework/com.android.location.provider.jar' does not exist or contains no resources. 
04-06 02:29:37.336 5324-5324/flo.myapplication I/Google Maps Android API﹕ Google Play services client version: 7095000 
04-06 02:29:37.361 5324-5324/flo.myapplication I/Google Maps Android API﹕ Google Play services package version: 7097470 
04-06 02:29:37.396 5324-5336/flo.myapplication I/art﹕ Background sticky concurrent mark sweep GC freed 0(0B) AllocSpace objects, 0(0B) LOS objects, 1% free, 2MB/2MB, paused 5.461ms total 9.101ms 
04-06 02:29:37.582 5324-5336/flo.myapplication I/art﹕ Background partial concurrent mark sweep GC freed 45498(2MB) AllocSpace objects, 11(2MB) LOS objects, 29% free, 9MB/13MB, paused 999us total 105.746ms 
04-06 02:29:37.835 5324-5324/flo.myapplication I/Choreographer﹕ Skipped 32 frames! The application may be doing too much work on its main thread. 
04-06 02:29:37.924 5324-5339/flo.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
04-06 02:29:37.924 5324-5339/flo.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa6078180, error=EGL_SUCCESS 
04-06 02:29:37.977 5324-5358/flo.myapplication D/All Products:﹕ {"products":[{"pid":"1","x_coordinate":"50","y_coordinate":"8","created_at":"2015-04-06 01:13:22","updated_at":"0000-00-00 00:00:00"}],"success":1} 
04-06 02:29:37.978 5324-5358/flo.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1 
    Process: flo.myapplication, PID: 5324 
    java.lang.RuntimeException: An error occured while executing doInBackground() 
      at android.os.AsyncTask$3.done(AsyncTask.java:300) 
      at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
      at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
      at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
      at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
      at java.lang.Thread.run(Thread.java:818) 
    Caused by: java.lang.IllegalStateException: Not on the main thread 
      at com.google.l.a.cd.b(Unknown Source) 
      at com.google.maps.api.android.lib6.c.ca.a(Unknown Source) 
      at com.google.maps.api.android.lib6.c.el.a(Unknown Source) 
      at com.google.android.gms.maps.internal.l.onTransact(SourceFile:167) 
      at android.os.Binder.transact(Binder.java:380) 
      at com.google.android.gms.maps.internal.IGoogleMapDelegate$zza$zza.addMarker(Unknown Source) 
      at com.google.android.gms.maps.GoogleMap.addMarker(Unknown Source) 
      at flo.myapplication.MapsActivity$retrieveAndAddCities.doInBackground(MapsActivity.java:200) 
      at flo.myapplication.MapsActivity$retrieveAndAddCities.doInBackground(MapsActivity.java:174) 
      at android.os.AsyncTask$2.call(AsyncTask.java:288) 
      at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
            at java.lang.Thread.run(Thread.java:818) 
04-06 02:29:38.024 5324-5357/flo.myapplication D/﹕ HostConnection::get() New Host Connection established 0x9fbe30a0, tid 5357 
04-06 02:29:38.833 5324-5336/flo.myapplication I/art﹕ Background partial concurrent mark sweep GC freed 10277(451KB) AllocSpace objects, 32(1505KB) LOS objects, 23% free, 13MB/17MB, paused 795us total 118.120ms

来源

2015-04-06 etrex2k4

请将您的错误或异常发布到logcat中。 – Aakash 2015-04-06 01:31:19

我加了logcat @ user3541465 – etrex2k4 2015-04-06 01:59:08

你应该使用异步任务而不是使用线程。这将是更好的选择，因为线程阻止你的操作。 – Aakash 2015-04-06 02:05:16

您的应用程序崩溃是因为您尝试更新主线程的UI。您的JSON请求成功，但是当您的代码碰到mMap.addMarker（）时，该应用会崩溃。

http://developer.android.com/guide/components/processes-and-threads.html

使用的AsyncTask是一个好主意，但你必须只能做在doInBackground（JSON的请求），因为doInBackground不主线程上运行，你的应用程序会崩溃它目前也是同样的道理。如果您使用AsyncTask，请查看文档。谷歌有一个很好的例子。

http://developer.android.com/reference/android/os/AsyncTask.html

我修改了retrieveAndAddCities类才能正常工作。 doInBackground现在返回一个JSONArray的产品。当doInBackground完成时，产品的JSONArray将作为onPostExecute中的参数传递。 onPostExecute在主线程上运行。它现在包含您循环浏览产品并添加地图标记的for循环。

class retrieveAndAddCities extends AsyncTask< Void, Void, JSONArray > { 
    protected JSONArray doInBackground(Void... args) { 
     List params = new ArrayList(); 
     // getting JSON string from URL 
     JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params); 

     // Check your log cat for JSON reponse 
     Log.d("All Products: ", json.toString()); 

     try { 
      // Checking for SUCCESS TAG 
      int success = json.getInt(TAG_SUCCESS); 

      if (success == 1) { 
       // products found 
       // Getting Array of Products 
       return json.getJSONArray(TAG_Coordinates); 
      } 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
     return null; 
    } 

    protected void onPostExecute(JSONArray products) { 
     if (products != null) { 
      for (int i = 0; i < products.length(); i++) { 
       JSONObject c = null; 
       try { 
        c = products.getJSONObject(i); 
        // Storing each json item in variable 
        int id = c.getInt(TAG_PID); 
        double x_coordinate = c.getDouble(TAG_X); 
        double y_coordinate = c.getDouble(TAG_Y); 
        mMap.addMarker(new MarkerOptions() 
          .position(new LatLng(x_coordinate, y_coordinate))); 
       } catch (JSONException e) { 
        e.printStackTrace(); 
       } 
      } 
     } else { 
      //Handle case of no products or failure 
     } 
    } 
}

来源

2015-04-06 02:32:11

感谢您的快速答案，我编辑我的帖子与我的新代码和一个asynctask，但我崩溃，所以我认为这是我的问题是双变量？要么？ – etrex2k4 2015-04-06 02:39:35

和以前一样，addMarker仍然在for循环中的主线程中被调用。 – 2015-04-06 02:44:07

如果您想更恰当地使用asynctask，请在doInBackground（）中返回JSON请求的结果并覆盖onPostExecute（）。在主线程上调用onPostExecute并将接收doInBackground（）的结果作为参数。移动您的for循环，在那里添加地图标记。 – 2015-04-06 02:52:59

好吧，那么你可以使用这样的异步任务，我的代码中可能有一些语法错误，但你可以像这样做。

public class myclass extends Asynctask<Void,Void,Void>{ 
@Override 
public void doInBackground(){ 
    retrieveAndAddCities(); } 
}

来源

2015-04-06 02:19:34 Aakash

Android Google Maps v2从JSON数组添加地图标记php mySQL

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