android - Reason behind null pointer exception? -


i using pager adapter display images in view pager ,that downloaded bitmapfactory in asynctask.

pageradapter class:

public class pageradapter extends pageradapter {     button load_img;     imageview imgview;     bitmap bitmap;        context mcontext;     layoutinflater mlayoutinflater;     list<string> l = mainactivity.list;     imageloader mimageloader;      public pageradapter(context context) {         mcontext = context;       }      @override     public int getcount() {         return 4;     }       @override     public object instantiateitem(viewgroup container, int position) {         imageloader mimageloader = imageloader.getinstance();         mlayoutinflater = ((layoutinflater) container.getcontext().getsystemservice(context.layout_inflater_service));         view view = mlayoutinflater.inflate(r.layout.img, container, false);           imgview = (imageview) view.findviewbyid(r.id.imageview3);  bitmap btp=new loadimage().doinbackground(l.get(position));         imgview.setimagebitmap(btp);          container.addview(view);          return view;     }      @override     public void destroyitem(viewgroup container, int position, object object) {         container.removeview((linearlayout) object);     }      @override     public boolean isviewfromobject(view view, object object) {         return view == object;     }      public class loadimage extends asynctask<string, string, bitmap> {          progressdialog pdialog = new progressdialog(mcontext);         @override         protected void onpreexecute() {             super.onpreexecute();              pdialog.setmessage("loading image ....");             pdialog.show();          }         protected bitmap doinbackground(string... args) {              try {                 bitmap = bitmapfactory.decodestream((inputstream) new url(args[0]).getcontent());              } catch (exception e) {                 e.printstacktrace();             }             return bitmap;         }          protected void onpostexecute(bitmap image) {              if(image != null){                 imgview.setimagebitmap(image);                 pdialog.dismiss();              }else{                  pdialog.dismiss();                 toast.maketext(mcontext, "image not exist or network error", toast.length_short).show();              }         }     }  }

my logcat:

02-08 18:49:22.554 18345-18345/autogenie.dg10 e/androidruntime: fatal exception: main java.lang.nullpointerexception @ autogenie.dg10.pageradapter$loadimage.doinbackground(pageradapter.java:89) @ autogenie.dg10.pageradapter.instantiateitem(pageradapter.java:54) @ android.support.v4.view.viewpager.addnewitem(viewpager.java:870) @ android.support.v4.view.viewpager.populate(viewpager.java:1020) @ android.support.v4.view.viewpager.populate(viewpager.java:952) @ android.support.v4.view.viewpager.onmeasure(viewpager.java:1474) @ android.view.view.measure(view.java:15518) @ android.widget.relativelayout.measurechildhorizontal(relativelayout.java:681) @ android.widget.relativelayout.onmeasure(relativelayout.java:461) @ android.view.view.measure(view.java:15518) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4825) @ android.widget.framelayout.onmeasure(framelayout.java:310) @ android.support.v7.widget.contentframelayout.onmeasure(contentframelayout.java:135) @ android.view.view.measure(view.java:15518) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4825) @ android.support.v7.widget.actionbaroverlaylayout.onmeasure(actionbaroverlaylayout.java:391) @ android.view.view.measure(view.java:15518) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4825) @ android.widget.framelayout.onmeasure(framelayout.java:310) @ android.view.view.measure(view.java:15518) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4825) @ android.widget.linearlayout.measurechildbeforelayout(linearlayout.java:1404) @ android.widget.linearlayout.measurevertical(linearlayout.java:695) @ android.widget.linearlayout.onmeasure(linearlayout.java:588) @ android.view.view.measure(view.java:15518) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4825) @ android.widget.framelayout.onmeasure(framelayout.java:310) @ com.android.internal.policy.impl.phonewindow$decorview.onmeasure(phonewindow.java:2176) @ android.view.view.measure(view.java:15518) @ android.view.viewrootimpl.performmeasure(viewrootimpl.java:1874) @ android.view.viewrootimpl.measurehierarchy(viewrootimpl.java:1089) @ android.view.viewrootimpl.performtraversals(viewrootimpl.java:1265) @ android.view.viewrootimpl.dotraversal(viewrootimpl.java:989) @ android.view.viewrootimpl$traversalrunnable.run(viewrootimpl.java:4351) @ android.view.choreographer$callbackrecord.run(choreographer.java:749) @ android.view.choreographer.docallbacks(choreographer.java:562) @ android.view.choreographer.doframe(choreographer.java:532) @ android.view.choreographer$framedisplayeventreceiver.run(choreographer.java:735) @ android.os.handler.handlecallback(handler.java:725) @ android.os.handler.dispatchmessage(handler.java:92) @ android.os.looper.loop(looper.java:137) @ android.app.activitythread.main(activitythread.java:5041) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:511) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:793) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:560) @ dalvik.system.nativestart.main(native method)

wrong way call asynctask. don't directly call doinbackground().

change 

bitmap btp=new loadimage().doinbackground(l.get(position));

to

bitmap btp = new loadimage().execute(l.get(position));

Comments

Post a Comment

Popular posts from this blog

javascript - jQuery: Add class depending on URL in the best way -

i have html progress meter: <div class="col-md-3" style="margin-left: -20px;"> <div class="progress-pos active" id="progess-1"> <div class="progress-pos-inner"> login </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-2"> <div class="progress-pos-inner"> scan items </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-3"> <div class="progress-pos-inner"> confirm address </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-4"> <div class="progress-pos-in...
Read more

caching - How to check if a url path exists in the service worker cache -

i need check if particular url path exists in service worker cache. example, suppose url is: /myserviceworker/service?a=110&b=70 this url exists in cache, there many of them different values of , b. now, suppose want refresh of these urls, how can that? i want know how access key values service worker cache. if know key, plan follows: var url = new url(key); if(url.pathname === "\/myserviceworker/service") refetch key but not sure how cache key , in format is. mean, string or url? cache api has match() method returns promise resolving in response object if match or undefined if no match exists. second parameter object can specify ignoresearch not take account url parameters. the ignoresearch option supported firefox ( chrome status here ). in other hand, retrieve cache entries, can use keys() method.
Read more

Redirect to a HTTPS version using .htaccess -

i need modify .htaccess file redirect urls https version without "www". http://example.com --> https://example.com http://www.example.com --> https://example.com https://www.example.com --> https://example.com this how .htaccess file looks like: rewriteengine on rewritecond %{request_filename} !-d rewritecond %{request_filename} !-f rewriterule ^(.*)$ redirect.php?id=$1&page=$2 [qsa,l] what modifications need make .htaccess in order forward https without "www"? it depends on doing current code. looks file called redirect trying display php page seo friendly url. think might confusing people. anyway, need , force https without www, need 1 more rule above. also second rule needs two capture groups in rewriterule test string because wanting 2 different values using $1 , $2 references. rewriteengine on #rediect www non www and/or http https --- combinations. rewritecond %{http_host} !^example\.com [nc,or] rewritecond %{https} !^...
Read more