Yellow highlight while using custom Toast in android -

i trying implement custom toast , below code wrote , hooked onclickelistner asusual

button customtoastbutton = (button) this.findviewbyid(r.id.add_to_cart);         customtoastbutton.setonclicklistener(new view.onclicklistener() {             public void onclick(view v) {                  //get layoutinflater , inflate custom_toast layout                 layoutinflater inflater = getlayoutinflater();                 view layout = inflater.inflate(r.layout.cart_toast, (viewgroup)                         findviewbyid(r.id.toast_layout_root));                  //get textview custom_toast layout                 textview text = (textview) layout.findviewbyid(r.id.toasttext);                 text.settext("item been added cart");                  //create toast object, set display duration,                 //set view layout that's inflated above , call show()                 toast t = new toast(getapplicationcontext());                 t.setduration(toast.length_short);                 t.setview(layout);                 t.show();             }         });  

and code used highlighted in yellow showing below error.well it's not showing error in logcat , code works fine.the highlightend part says ' may produce 'java.lang.nullpointerexception'

method invocation 'customtoastbutton.setonclicklistener(new view.onclicklistener() {              public void onclick(vi...' may produce 'java.lang.nullpointerexception' less... (ctrl+f1)      inspection analyzes method control , data flow report possible conditions true or false, expressions value statically proven constant, , situations can lead nullability contract violations.     variables, method parameters , return values marked @nullable or @notnull treated nullable (or not-null, respectively) , used during analysis check nullability contracts, e.g. report possible nullpointerexception errors.     more complex contracts can defined using @contract annotation, example:     @contract("_, null -> null") — method returns null if second argument null  @contract("_, null -> null; _, !null -> !null") — method returns null if second argument null , not-null otherwise  @contract("true -> fail") — typical assertfalse method throws exception if true passed      inspection can configured use custom @nullable     @notnull annotations (by default ones annotations.jar used) 

i don't understand reason causing error,i kindly request have @ it. thankyou in advance

you check if customtoastbutton not null before setting onclicklistener

if(customtoastbutton!=null){     customtoastbutton.setonclicklistener(...) ... } 

the warning shown, because if button not exist , continue working nullpointerexception thrown.