java - Unable To Create CardView Fragment -

i have no idea on wrong code.

my application using navigation drawer. there 4 different fragments , 1 of cardview fragment have converted earlier activity fragment.

the cardview fragment being underlined red shows error not able compiled. kindly refer attached pictures.

if accept proposed solutions android studio,it solve cardviewfragment , new problem occur @ other 3 fragments.

and both main activity , cardview fragment.

mainactivity.java

package info.androidhive.materialdesign.activity;  import android.os.bundle; import android.support.v4.app.fragment; import android.support.v4.app.fragmentmanager; import android.support.v4.app.fragmenttransaction; import android.support.v4.widget.drawerlayout; import android.support.v7.app.appcompatactivity; import android.support.v7.widget.toolbar; import android.view.menu; import android.view.menuitem; import android.view.view; import android.widget.toast;  import info.androidhive.materialdesign.r;  public class mainactivity extends appcompatactivity implements fragmentdrawer.fragmentdrawerlistener {      private static string tag = mainactivity.class.getsimplename();      private toolbar mtoolbar;     private fragmentdrawer drawerfragment;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          mtoolbar = (toolbar) findviewbyid(r.id.toolbar);          setsupportactionbar(mtoolbar);         getsupportactionbar().setdisplayshowhomeenabled(true);          drawerfragment = (fragmentdrawer)                 getsupportfragmentmanager().findfragmentbyid(r.id.fragment_navigation_drawer);         drawerfragment.setup(r.id.fragment_navigation_drawer, (drawerlayout) findviewbyid(r.id.drawer_layout), mtoolbar);         drawerfragment.setdrawerlistener(this);          // display first navigation drawer view on app launch         displayview(0);     }       @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.menu_main, menu);         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {         // handle action bar item clicks here. action bar         // automatically handle clicks on home/up button, long         // specify parent activity in androidmanifest.xml.         int id = item.getitemid();          //noinspection simplifiableifstatement         if (id == r.id.action_settings) {             return true;         }          if(id == r.id.action_search){             toast.maketext(getapplicationcontext(), "search action selected!", toast.length_short).show();             return true;         }          return super.onoptionsitemselected(item);     }      @override     public void ondraweritemselected(view view, int position) {         displayview(position);     }      private void displayview(int position) {         fragment fragment = null;         string title = getstring(r.string.app_name);         switch (position) {             case 0:                 fragment = new homefragment();                 title = getstring(r.string.title_home);                 break;             case 1:                 fragment = new friendsfragment();                 title = getstring(r.string.title_friends);                 break;             case 2:                 fragment = new messagesfragment();                 title = getstring(r.string.title_messages);                 break;             case 3:                 fragment = new cardviewfragment();                 title = getstring(r.string.title_messages);                 break;             default:                 break;         }          if (fragment != null) {             fragmentmanager fragmentmanager = getsupportfragmentmanager();             fragmenttransaction fragmenttransaction = fragmentmanager.begintransaction();             fragmenttransaction.replace(r.id.container_body, fragment);             fragmenttransaction.commit();              // set toolbar title             getsupportactionbar().settitle(title);         }     } } 

cardviewfragment.java

package info.androidhive.materialdesign.activity;  import android.app.activity; import android.app.fragment; import android.os.bundle; import android.support.v4.app.fragmentactivity; import android.support.v7.app.actionbaractivity; import android.support.v7.widget.cardview; import android.support.v7.widget.gridlayoutmanager; import android.support.v7.widget.linearlayoutmanager; import android.support.v7.widget.recyclerview; import android.support.v7.widget.staggeredgridlayoutmanager; import android.support.v7.widget.toolbar; import android.view.layoutinflater; import android.view.menu; import android.view.menuitem; import android.view.view; import android.view.viewgroup; import android.widget.linearlayout;  import java.util.arraylist;  import info.androidhive.materialdesign.r;   public class cardviewfragment extends fragment {      private toolbar toolbar;     private recyclerview recyclerview;     private cardview cardview;      private arraylist<feddproperties> os_versions;      private recyclerview.adapter madapter;     // private recyclerview.layoutmanager mlayoutmanager;       private linearlayout lllayout;     private fragmentactivity faactivity;     @override     /*protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          initcontrls();     }*/     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate){         faactivity=(fragmentactivity)                 super.getactivity();         lllayout=(linearlayout)                 inflater.inflate(r.layout.activity_main, container, false);          initcontrls();          return lllayout;     }      private void initcontrls() {          //toolbar = (toolbar) findviewbyid(r.id.toolbar);         //  cardview = (cardview) findviewbyid(r.id.cardlist);         recyclerview = (recyclerview) lllayout.findviewbyid(r.id.my_recycler_view);          /*if (toolbar != null) {             setsupportactionbar(toolbar);             getsupportactionbar().settitle("android versions");          }*/          final string[] versions = {"alpha", "beta", "cupcake", "donut",                 "eclair", "froyo", "gingerbread", "honeycomb",                 "ice cream sandwitch", "jellybean", "kitkat", "lollypop"};         final int[] icons = {r.drawable.ic_launcher, r.drawable.ic_launcher, r.drawable.ic_launcher, r.drawable.donut, r.drawable.eclair, r.drawable.froyo, r.drawable.gingerbread, r.drawable.honeycomb, r.drawable.icecream_sandwhich, r.drawable.jellybean, r.drawable.kitkat, r.drawable.lollipop};           os_versions = new arraylist<feddproperties>();          (int = 0; < versions.length; i++) {             feddproperties feed = new feddproperties();              feed.settitle(versions[i]);             feed.setthumbnail(icons[i]);             os_versions.add(feed);         }          recyclerview.sethasfixedsize(true);          // listview         recyclerview.setlayoutmanager(new linearlayoutmanager(getactivity()));          //grid view         // recyclerview.setlayoutmanager(new gridlayoutmanager(this,2,1,false));          //staggeredgridview         // recyclerview.setlayoutmanager(new staggeredgridlayoutmanager(2,1));          // create object adapter         madapter = new cardviewdataadapter(os_versions);          // set adapter object recyclerview         recyclerview.setadapter(madapter);       }     /*  @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.menu_main, menu);         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {         // handle action bar item clicks here. action bar         // automatically handle clicks on home/up button, long         // specify parent activity in androidmanifest.xml.         int id = item.getitemid();          //noinspection simplifiableifstatement         if (id == r.id.action_settings) {             return true;         }          return super.onoptionsitemselected(item);     }*/ } 

in mainactivity.java, declared

import android.support.v4.app.fragment 

import same type of fragment in cardviewfragment.java instead of

 import android.app.fragment; 

so it's clear same type of fragment being used in both pieces of code.