我正在開發一個具有其他Web服務的應用程序。通過從服務器獲取json響應,解析它並使用適配器將其填充到自定義列表視圖中。在那個JSON響應中有url的下載圖像以顯示在列表項中。每一件事情都已經完成,工作正常,除了從URL加載圖像有Nullpointer異常。 我已經做了調試也,logcat的說明如下從url中加載圖像時發生Nullpointer異常
java.lang.NullPointerException
at android.widget.AbsListView.obtainView(AbsListView.java:2269)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1244)
at android.widget.ListView.onMeasure(ListView.java:1156)
at android.view.View.measure(View.java:15172)
at android.widget.RelativeLayout.measureChild(RelativeLayout.java:602)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:415)
at android.view.View.measure(View.java:15172)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15172)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:833)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
at android.view.View.measure(View.java:15172)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2
at android.view.View.measure(View.java:15172)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1848)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1100)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1273)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
at android.view.Choreographer.doCallbacks(Choreographer.java:555)
at android.view.Choreographer.doFrame(Choreographer.java:525)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Force finishing activity com.shopping/.views.JsonListView
有人能幫我找到原因,讓這個異常。
編輯:
int loader = R.drawable.fb_icon;
// ImageLoader class instance
ImageLoader imgLoader = new ImageLoader(_Context);
imgLoader.DisplayImage(imageUrl, loader, holder.productImage);
public void DisplayImage(String url, int loader, ImageView imageView)
{
stub_id = loader;
imageViews.put(imageView, url);
Bitmap bitmap=memoryCache.get(url);
if(bitmap!=null)
imageView.setImageBitmap(bitmap);
else
{
queuePhoto(url, imageView);
imageView.setImageResource(loader);
}
}
一些源代碼將是有益的... – RvdK
@Androholic請張貼一些代碼,以便我們可以幫助您更多,您使用的延遲加載列表視圖中的下載和顯示圖像。 –
是的,我正在使用延遲加載。並請檢查編輯 – Androholic