java - Runtime Exception in Dynamic Fragments -

i trying create activity load different fragments dynamically. how main activity like

import android.os.bundle; import android.app.activity; import android.app.fragment; import android.app.fragmenttransaction;     public class user_details extends activity {     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_fragment_loader);         fragment fragment=new mail_fragment();          fragmenttransaction fragmenttransaction =               getfragmentmanager().begintransaction();           fragmenttransaction.add(r.id.fragment_place, fragment);           fragmenttransaction.commit();  } 

i getting following error during run time. please check error here

the fragment this

import android.app.fragment; import android.os.bundle; import android.view.layoutinflater; import android.view.view; import android.view.viewgroup;     public class mail_fragment extends fragment { @override public view oncreateview(layoutinflater inflater,                          viewgroup container, bundle savedinstancestate) {     return inflater.inflate(r.layout.fragment_mail, container, false); }} 

the xml file of main activity(user_details) activity_fragment_loader

<?xml version="1.0" encoding="utf-8"?>  <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">  <button     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="ask me later"     android:id="@+id/but_skip"     android:layout_alignparentbottom="true"     android:layout_centerhorizontal="true" /> <fragment     android:id="@+id/fragment_place"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:layout_above="@+id/but_skip"     android:layout_alignparentleft="true"     android:layout_alignparentstart="true" />     </relativelayout> 

the xml file of mail_fragment activity is

<?xml version="1.0" encoding="utf-8"?> <framelayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent" android:layout_height="match_parent">  <textview     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:textappearance="?android:attr/textappearancemedium"     android:text="enter e-mail id"     android:id="@+id/mail"     android:layout_alignparenttop="true"     android:layout_centerhorizontal="true"     android:layout_margintop="119dp"     android:textcolor="#000000"     android:layout_gravity="center_horizontal|top" />  <edittext     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:inputtype="textemailaddress"     android:ems="10"     android:id="@+id/edittext"     android:layout_centervertical="true"     android:layout_alignparentleft="true"     android:layout_alignparentstart="true"     android:layout_alignparentright="true"     android:layout_alignparentend="true"     android:layout_gravity="center" />  </framelayout> 

i have referred similar questions. of them suggest place setcontentview() in user_details activity after committing fragmenttracsaction. have tried still getting same error.

i add statically embeded fragment in xml file , working perfectly. when pragmatically throwing me error.

any appreciated

the fragmenttransaction.add method takes id of viewgroup adding fragment, not id of fragment. have 2 alternates, either specify name attribute of fragment in xml like

<fragment android:name="your_package_name.mail_fragment" android:id="@+id/fragment_place" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_above="@+id/but_skip" android:layout_alignparentleft="true" android:layout_alignparentstart="true" /> 

and in java, instead of calling

fragment fragment = new mail_fragment(); 

use

fragment fragment = (fragment)findviewbyid(r.id.fragment_place); 

and remaining usual.

the other alternate not add fragment xml of activity, create in java. in case, have specify viewgroup id in fragmenttransaction.add() method. hope helps.