Error: The method replace (int, Fragment) in the type fragmenttransaction are not applicable for the arguments (int, myfragment)

Fragment newfragment =new myfragment ();
Fragmenttransaction.replace (r.layout.activity_main,newfragment). commit ();

Hint Error: The method replace (int, Fragment) in the type fragmenttransaction are not applicable for the arguments (int, myfragmen T

Mom eggs, looking for a long time! Always assume that a subclass object cannot be assigned to a parent class reference. This science!

Error code:

 Packagecom.example.testforfragment;ImportAndroid.os.Bundle;Importandroid.app.Activity;ImportAndroid.app.FragmentManager;Importandroid.app.FragmentTransaction;Importandroid.support.v4.app.Fragment;Importandroid.support.v4.app.fragment.*;ImportAndroid.view.Menu; Public classMainactivityextendsActivity {@Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); Fragmentmanager Fragmentmanager=Getfragmentmanager (); Fragmenttransaction fragmenttransaction=fragmentmanager.begintransaction (); Fragment newfragment=Newmyfragment ();    Fragmenttransaction.replace (r.layout.activity_main,newfragment). commit (); } @Override Public BooleanOncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.main, menu); return true; }}

Modify:

 Packagecom.example.testforfragment;ImportAndroid.os.Bundle;Importandroid.app.Activity;Importandroid.support.v4.app.Fragment;Importandroid.support.v4.app.FragmentActivity;ImportAndroid.support.v4.app.FragmentManager;Importandroid.support.v4.app.FragmentTransaction;ImportAndroid.view.Menu; Public classMainactivityextendsfragmentactivity {@Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); Fragmentmanager Fragmentmanager=Getsupportfragmentmanager (); Fragmenttransaction fragmenttransaction=fragmentmanager.begintransaction (); Fragment newfragment=Newmyfragment ();    Fragmenttransaction.replace (r.layout.activity_main,newfragment). commit (); } @Override Public BooleanOncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.main, menu); return true; }}

1. Imported Packages

2.extends

3.getSurpport ...