android - java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity -

i trying use alert dialog on delete button. showing exception show dialog. when click on delete crashes , shows exception on .show.

i tried use theme.appcompat theme activity still crashes.

   <activity android:name=".addeventactivity"         android:theme="@style/theme.appcompat">     </activity>           delete.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                  new alertdialog.builder(getapplicationcontext())                         .settitle("delete entry")                         .setmessage("are sure want delete entry?")                         .setpositivebutton(android.r.string.yes, new dialoginterface.onclicklistener() {                             public void onclick(dialoginterface dialog, int which) {                                  toast.maketext(getapplicationcontext(), "yaay", toast.length_short).show();                                 = new intent();                                 db.deleteevent(eventdata);                                 log.i("d", "delete");                                 setresult(result_ok, i);                                 finish();                                  // continue delete                             }                         })                         .setnegativebutton(android.r.string.no, new dialoginterface.onclicklistener() {                             public void onclick(dialoginterface dialog, int which) {                                 // nothing                             }                         })                         .seticon(android.r.drawable.ic_dialog_alert)                         .show();             }         }); 

my theme

     <!-- base application theme. -->     <style name="apptheme" parent="theme.appcompat.light.noactionbar">         <!-- customize theme here. -->         <item name="colorprimary">@color/colorprimary</item>         <item name="colorprimarydark">@color/colorprimarydark</item>         <item name="coloraccent">@color/coloraccent</item>          <item name="windowactionbaroverlay">false</item>          <item name="windowactionbar">false</item>          <item name="windownotitle">true</item>         <item name="android:windowbackground">@color/background_material_light</item>     </style>     <style name="apptheme.appbaroverlay" parent="themeoverlay.appcompat.dark.actionbar" />     <style name="apptheme.popupoverlay" parent="themeoverlay.appcompat.light" />  </resources> 

thank you.

u using wrong context have use activity context , not application context

change:

  new alertdialog.builder(getapplicationcontext()) 

to

  new alertdialog.builder(youractivityname.this)