单身类，主要活动没有获取数据和不解析jsonrequest

我没有选择做什么和问题来自哪里。我尝试了各种方案来获得解决方案，但似乎没有任何解决方案。这是误差输出：单身类，主要活动没有获取数据和不解析jsonrequest

06-09 14:33:44.082 3383-3383/wait.com.linasblog E/AndroidRuntime: FATAL EXCEPTION: main 
Process: wait.com.linasblog, PID: 3383 
java.lang.RuntimeException: Unable to start activity ComponentInfo{wait.com.linasblog/wait.com.linasblog.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void wait.com.linasblog.AppController.addToRequestQueue(com.android.volley.Request)' on a null object reference 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void wait.com.linasblog.AppController.addToRequestQueue(com.android.volley.Request)' on a null object reference 
at wait.com.linasblog.MainActivity.getJsonPosts(MainActivity.java:208) 
at wait.com.linasblog.MainActivity.onCreate(MainActivity.java:42) 
at android.app.Activity.performCreate(Activity.java:6237) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

这是我的请求方法：

public void getJsonPosts(){ 


     RequestSingleton.getInstance(this.getApplicationContext()).getRequestQueue(); 
    // RequestQueue queue = RequestSingleton.getInstance(this.getApplicationContext()).getRequestQueue(); 
//  queue.start(); 
     String url = "http://linagrey.blogspot.com/feeds/posts/default?alt=json"; 


     JsonObjectRequest jsonRequest = new JsonObjectRequest(Request.Method.GET,url,null, new Response.Listener<JSONObject>() { 
      @Override 
      public void onResponse(JSONObject response) { 
       try { 
        JSONObject feedResponse = response.getJSONObject("feed"); 
        JSONArray entryArrayPosts = feedResponse.getJSONArray("entry"); 
        BlogPost bp; 
        for (int i = 0; i < entryArrayPosts.length(); i++){ 
         bp = new BlogPost(); 
         //Get the entry as an array and loop through 
         JSONObject entryBlogPost = entryArrayPosts.getJSONObject(i); 

         //Get the title from the array 
         JSONObject postObject = entryBlogPost.getJSONObject("title"); 
         //JSONObject postHtmlContent = entryBlogPost.getJSONObject(KEYS.POST_JSON_OBJECT_HTML_CONTENT); 

         //GET LINK ARRAY FROM JSON 
         JSONArray linkAddress = entryBlogPost.getJSONArray(KEYS.POST_JSON_ARRAY_OBJECT); 

         if(entryBlogPost.has(KEYS.MEDIA_THUMBNAIL)) { 
          JSONObject imageObjectUrl = entryBlogPost.getJSONObject(KEYS.MEDIA_THUMBNAIL); 
          String thumbnailUrl = imageObjectUrl.getString(KEYS.MEDIA_THUMBNAIL_URL); 
          bp.setmUrlThumbnail(thumbnailUrl); 
         } 

         //for loop for link array object 
         for (int j = 0;j < linkAddress.length(); j++){ 
          JSONObject eachLink = linkAddress.getJSONObject(4); 
          String htmlUrl = eachLink.getString(KEYS.POST_HTML_LINK); 
          bp.setmLinkContent(htmlUrl); 
         } 


         //Get title string contained in Title Object 
         String title = postObject.getString(KEYS.POST_TITLE); 
         Log.v(TAG, "OBJECTS HAVE THIS PROPERTIES: " + i + " " + title); 


         //Set Properties Gotten 
         bp.setmTitle(title); 

         Log.v(TAG, "OBJECTS HAVE THIS PROPERTIES: " + i + " " + bp.toString()); 
         //Add a blog post Object to the Arraylist 
         postArrayList.add(bp); 


        } 
        // Log.v(TAG, "Arraylist SIZE " + postArrayList.size()); 

        for(BlogPost posts : postArrayList){ 
         Log.v(TAG, posts + " "); 
        } 

        // Toast.makeText(this.,response.toString(),Toast.LENGTH_LONG).show(); 

       }catch(JSONException e){ 
        Log.v(TAG, e.toString()); 
       } 
      } 
     },new Response.ErrorListener(){ 
      @Override 
      public void onErrorResponse(VolleyError error) { 
       Log.v(TAG, error.toString()); 
      } 
     }); 
     RequestSingleton.getInstance(this).addToRequestQueue(jsonRequest); 
    }

这是我的Singleton类：

public class RequestSingleton { 

    private static RequestSingleton mInstance ; 
    private RequestQueue mRequestQueue; 
    private ImageLoader mImageLoader; 
    private static Context mCtx; 

     private RequestSingleton(Context context){ 
      mCtx = context; 
      mRequestQueue = getRequestQueue(); 

      mImageLoader = new ImageLoader(mRequestQueue, new ImageLoader.ImageCache(){ 

       private final LruCache<String, Bitmap> cache = new LruCache<String, Bitmap>(20); 

       @Override 
       public Bitmap getBitmap(String url) { 
        return cache.get(url); 
       } 

       @Override 
       public void putBitmap(String url, Bitmap bitmap) { 
        cache.put(url, bitmap); 
       } 
      }); 
     } 

    public static synchronized RequestSingleton getInstance(Context context){ 
     if (mInstance == null){ 
      mInstance = new RequestSingleton(context); 
     } 
     return mInstance; 
    } 

    public RequestQueue getRequestQueue(){ 
     if(mRequestQueue == null){ 
      mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext()); 
     } 
     return mRequestQueue; 
    } 

    public <T> void addToRequestQueue(Request<T> req){ 
     getRequestQueue().add(req); 
    } 
    public ImageLoader getImageLoader(){ 
     return mImageLoader; 
    } 




}

这是清单文件：

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

    <uses-permission android:name = "android.permission.INTERNET"/> 
    <uses-permission android:name= "android.permission.ACCESS_NETWORK_STATE"/> 

    <application 
     android:allowBackup="true" 
     android:icon="@mipmap/ic_launcher" 
     android:label="@string/app_name" 
     android:supportsRtl="true" 
     android:theme="@style/AppTheme"> 
     android:name = ".RequestSingleton" 

     <activity 
      android:name=".MainActivity" 
      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> 
    </application> 

</manifest>

来源

2016-06-09 caleb grimah

日志描述'com.linasblog.AppController.addToRequestQueue（com.android.volley.Request）'这意味着'addToRequestQueue（）'在'AppController'中，但是您发布的代码显示它在'RequestSingleton'中。请张贴正确的日志/代码。 –

我HV删除了应用程序控制器类...但应用程序一直指向它，我没有参考我的代码中的应用程序控制器类 –

清理项目并发布新的日志。 –

在你的R equestSingleton您正在获取空值

public <T> void addToRequestQueue(Request<T> req){ 
     getRequestQueue().add(req); 
    }

正如您将在日志中关于中途下降的错误日志中看到的那样。

来源

2016-06-09 22:21:43

为什么应该是解决方案 –

单身类，主要活动没有获取数据和不解析jsonrequest

回答

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