使用齐射库在我的图像加载器函数上出现空指针异常

Question

我正在尝试下载并在我的Android应用程序中将图像加载到我的NetworkImageView ..但我收到此错误

引起：java.lang.NullPointerException：尝试在空对象引用上调用虚方法'com.android.volley.toolbox.ImageLoader com.example.username.socialoid.AppController.getImageLoader（）'

不要发生什么事。通常由于声明错误而发生空指针，但我在这里没有犯错..请帮助..

这是我的代码snippiest

    // user profile pic
    profilePic.setImageUrl(item.getProfilePic(), imageLoader);

和imageloader在其他类中如下

private RequestQueue mRequestQueue;
private ImageLoader mImageLoader;

public ImageLoader getImageLoader() {
    getRequestQueue();
    if (mImageLoader == null) {
        getLruBitmapCache();
        mImageLoader = new ImageLoader(this.mRequestQueue, mLruBitmapCache);
    }

    return this.mImageLoader;
}

我的LruBitmapCache类

 import com.android.volley.toolbox.ImageLoader.ImageCache;
 import android.graphics.Bitmap;
 import android.support.v4.util.LruCache;

 public class LruBitmapCache extends LruCache<String, Bitmap> implements
    ImageCache {
 public static int getDefaultLruCacheSize() {
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
    final int cacheSize = maxMemory / 8;

    return cacheSize;
}

public LruBitmapCache() {
    this(getDefaultLruCacheSize());
}

public LruBitmapCache(int sizeInKiloBytes) {
    super(sizeInKiloBytes);
}

@Override
protected int sizeOf(String key, Bitmap value) {
    return value.getRowBytes() * value.getHeight() / 1024;
}

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

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

完成Log ::

11-30 15:35:39.635  27827-27827/com.example.hissamyousaf.socialoid E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.hissamyousaf.socialoid, PID: 27827
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hissamyousaf.socialoid/com.example.hissamyousaf.socialoid.Home}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hissamyousaf.socialoid/com.example.hissamyousaf.socialoid.NewsFeed}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.android.volley.toolbox.ImageLoader com.example.hissamyousaf.socialoid.AppController.getImageLoader()' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
            at android.app.ActivityThread.access$900(ActivityThread.java:177)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5942)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
     Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hissamyousaf.socialoid/com.example.hissamyousaf.socialoid.NewsFeed}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.android.volley.toolbox.ImageLoader com.example.hissamyousaf.socialoid.AppController.getImageLoader()' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693)
            at android.app.ActivityThread.startActivityNow(ActivityThread.java:2435)
            at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
            at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
            at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:776)
            at android.widget.TabHost.setCurrentTab(TabHost.java:435)
            at android.widget.TabHost.addTab(TabHost.java:262)
            at com.example.hissamyousaf.socialoid.Home.onCreate(Home.java:42)
            at android.app.Activity.performCreate(Activity.java:6289)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
            at android.app.ActivityThread.access$900(ActivityThread.java:177)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5942)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.android.volley.toolbox.ImageLoader com.example.hissamyousaf.socialoid.AppController.getImageLoader()' on a null object reference
            at com.example.hissamyousaf.socialoid.FeedListAdapter.<init>(FeedListAdapter.java:28)
            at com.example.hissamyousaf.socialoid.NewsFeed.onCreate(NewsFeed.java:43)
            at android.app.Activity.performCreate(Activity.java:6289)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
            at android.app.ActivityThread.startActivityNow(ActivityThread.java:2435)
            at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
            at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
            at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:776)
            at android.widget.TabHost.setCurrentTab(TabHost.java:435)
            at android.widget.TabHost.addTab(TabHost.java:262)
            at com.example.hissamyousaf.socialoid.Home.onCreate(Home.java:42)
            at android.app.Activity.performCreate(Activity.java:6289)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
            at android.app.ActivityThread.access$900(ActivityThread.java:177)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5942)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)