Develop Reference

NestedScrollView stops scrolling as soon as CollapsingToolbarLayout collapses

First let me clarify that i have found a few questions similar to this question, but none worked for me.
So i have one activity (MainActivity.java), which has a bottom navigation tab, each tab has its own fragment, the third fragment is named 'ServiceFragment.java' (also the third tab in Bottom navigation).
Classes:
ServiceFragment.java
package in.ikleen.ikleenservices;
import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class ServiceFragment extends Fragment {
Context context;
public ServiceFragment() {
// Required empty public constructor
}
#Override
public void onAttach (Context context){
super.onAttach(context);
this.context = context;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_service, container, false);
ViewPager viewPager = rootView.findViewById(R.id.service_view_pager);
viewPager.setOffscreenPageLimit(3);
TabLayout tabLayout = rootView.findViewById(R.id.service_tab_layout);
ServiceFragmentPageAdapter pageAdapter = new ServiceFragmentPageAdapter(context, getChildFragmentManager());
viewPager.setAdapter(pageAdapter);
tabLayout.setupWithViewPager(viewPager);
return rootView;
}
}
ServiceFragmentPageAdapter.java
package in.ikleen.ikleenservices;
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class ServiceFragmentPageAdapter extends FragmentPagerAdapter {
private Context mContext;
Fragment zero, first, second;
public ServiceFragmentPageAdapter (Context context, FragmentManager fm){
super(fm);
mContext = context;
zero = new WashDryServiceFragment();
first = new WashDryIronServiceFragment();
second = new AdditionalProductsServiceFragment();
}
#Override
public Fragment getItem(int position){
switch (position){
case 0:
return zero;
case 1:
return first;
case 2:
return second;
default:
return zero;
}
}
#Override
public int getCount(){
return 3;
}
#Override
public CharSequence getPageTitle(int position){
switch (position){
case 0:
return mContext.getString(R.string.wash_dry);
case 1:
return mContext.getString(R.string.wash_dry_iron);
case 2:
return mContext.getString(R.string.additional_products);
default:
return mContext.getString(R.string.wash_dry);
}
}
}
WashDryServiceFragment.java (the first tab of viewpager tablayout, also the one bearing the problem)
package in.ikleen.ikleenservices;
import android.annotation.TargetApi;
import android.os.Bundle;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.app.Fragment;
import android.support.v4.widget.NestedScrollView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toolbar;
import java.lang.annotation.Target;
import java.util.ArrayList;
import java.util.List;
public class WashDryServiceFragment extends Fragment {
public WashDryServiceFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_wash_dry_service, container, false);
ListView listView = (ListView) rootView.findViewById(R.id.listViewWashDryService);
ArrayList<String> stringList = new ArrayList<>();
for(int i=0; i<20; i++) {
stringList.add("Hello");
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, stringList);
listView.setAdapter(adapter);
//TESTED BELOW CODE BUT CANNOT EVEN SCROLL A LITTLE BIT SO COMMENTED IT
//Toolbar toolbar = (Toolbar) rootView.findViewById(R.id.toolbar1);
//NestedScrollView nestedScrollView = (NestedScrollView) rootView.findViewById(R.id.nestedScroll);
//CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) nestedScrollView.getLayoutParams();
//params.setBehavior(new ConstrainedScrollBehavior());
return rootView;
}
}
Layouts:
fragment_service.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="in.ikleen.ikleenservices.ServiceFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="#+id/service_tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabTextAppearance="#style/Base.TextAppearance.AppCompat.Small"
app:tabMode="fixed"/>
<android.support.v4.view.ViewPager
android:id="#+id/service_view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
</FrameLayout>
fragment_wash_dry_service.xml (THE PROBLEM LIES HERE)
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="in.ikleen.ikleenservices.WashDryServiceFragment">
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinatorlayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="150dp"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center_horizontal"
app:layout_collapseMode="parallax"
android:scaleType="centerInside"
app:layout_collapseParallaxMultiplier="0.5"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
android:src="#mipmap/ld_00"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="#+id/nestedScroll"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_gravity="fill_vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true"
android:orientation="vertical">
<ListView
android:id="#+id/listViewWashDryService"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/appBarLayout"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="JUST FOR TESTS"
android:textAppearance="#style/TextAppearance.AppCompat.Large"/>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
</FrameLayout>
Thanks

The problem in this case was: (p.s. i am stupid)
listview cannot scroll inside nestedscrollview, so as soon as the collapsingtoolbar collapsed, there was no need for the nestedscrollview to scroll more as it already filled the parent and listview could not scroll anyways. (i know, dumb explanation)
Solution:
1: either remove listview inside the nestedscrollview
OR
2: add this attribute android:nestedScrollingEnabled="true" inside nestedscrollview (not tested, but should work)

Unable to reference `fragment` using `R.id.myFirstFragment`

Here is the class of fragment
package com.hfad.chapter7;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class WorkoutDetailFragment extends Fragment {
private long workoutID;
public WorkoutDetailFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_workout_detail, container, false);
}
public void setWorkoutID(long workoutID) {
this.workoutID = workoutID;
}
}
And the layout it's using is:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.hfad.chapter7.WorkoutDetailFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/hello_blank_fragment" />
</FrameLayout>
My MainActivity is:
package com.hfad.chapter7;
import android.app.Activity;
import android.app.Fragment;
import android.provider.UserDictionary;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WokoutDetailFragment workoutDetailFragment;
workoutDetailFragment = (WorkoutDetailFragment)this.getFragmentManager().findFragmentById(R.id.myFirstFragment);
}
}
And layout of MainActivity is:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.hfad.chapter7.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
/>
<fragment
class="com.hfad.chapter7.WorkoutDetailFragment"
android:id="#+id/myFirstFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
Problem is when I use this.getFragmentManager().findFragmentById(R.id.myFirstFragment) in onCreate of AppCompatActivity I get Fragment though I should get WorkoutDetailFragment as stated here in a similar example.
UPDATE:
Also I am unable to cast Fragment to WorkDetailFragment

#user4913383,
Change this line:
workoutDetailFragment = (WorkoutDetailFragment)this.getFragmentManager().findFragmentById(R.id.myFirstFragment);
to
workoutDetailFragment = (WorkoutDetailFragment)this.getSupportFragmentManager().findFragmentById(R.id.myFirstFragment);

What's the problem of getting a fragment? The getFragmentManager().findFragmentById() method returns a Fragment and you have to cast it. Since you are casting the Fragment to a WorkoutDetailFragment you should be able to do what you want with it.

I think it has to be <fragment android:name="com.hfad.chapter7.WorkoutDetailFragment"... instead of class.
=> http://developer.android.com/training/basics/fragments/creating.html#AddInLayout

How to switch between fragments during onclick?

I have a project I'm trying to do. I ran into a little issue and I'm not sure how to get around it. Below is an image of the application so far.
What I would like it to do is when the user onclicks one of the list items, the part which says "Hello! It's Fragment2" changes to a new xml which I declared in the app. So if I click the ATO listItem, then the fragment on the right side should change to something like "Hello! It's ATO Fragment"
Here is my code so far:
AndroidListFragmentActivity:
package com.exercise.AndroidListFragment;
import android.app.Activity;
import android.os.Bundle;
public class AndroidListFragmentActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Fragment2:
package com.exercise.AndroidListFragment;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment2 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// TODO Auto-generated method stub
return inflater.inflate(R.layout.fragment2, container, false);
}
}
MyListFragment1:
package com.exercise.AndroidListFragment;
import android.app.ListFragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class MyListFragment1 extends ListFragment {
String[] options ={
"ATO",
"BETA",
"DELT",
"PHI DELT",
"SAE",
"SIG NU",
"FIJI",
"SIG CHI",
"PHI PSI"
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ListAdapter myListAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, options);
setListAdapter(myListAdapter);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.listfragment1, container, false);
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
Toast.makeText(getActivity(), getListView().getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
}
}
Fragment2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/fragment2text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Hello! It's Fragment2" />
</LinearLayout>
listfragment1.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="8dp"
android:paddingRight="8dp">
<ListView android:id="#id/android:list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:drawSelectorOnTop="false"/>
<TextView android:id="#id/android:empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="No data"/>
</LinearLayout>
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<fragment
android:name="com.exercise.AndroidListFragment.MyListFragment1"
android:id="#+id/fragment1"
android:layout_weight="1"
android:layout_width="0px"
android:layout_height="match_parent" />
<fragment
android:name="com.exercise.AndroidListFragment.Fragment2"
android:id="#+id/fragment2"
android:layout_weight="2"
android:layout_width="0px"
android:layout_height="match_parent" />
</LinearLayout>

Not sure what's the minimal fix to get your code working, but have you looked at using a Navigation Drawer to switch between the fragments? It looks to me like the example in the official docs matches pretty much exactly what you want to achieve.
A key is to have some kind of container for the currently displayed fragment (instead of using <fragment> like in your XML). For example:
<FrameLayout
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
Then, switching fragments goes something like this:
Fragment fragment = new Fragment2();
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment)
.commit();
Further reading: Add a Fragment to an Activity at Runtime in Android developer docs.

private void openFragment (int number) {
Fragment fragment = new Fragment();
switch (number) {
case FRAGMENT_1:
fragment = new *Fragment1*();
break;
case FRAGMENT_2:
fragment = new *Fragment2*();
break;
}
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_frame, fragment)
.commit();
}

Fragment is not covering entire screen

please help
When I run my ListFragment actitivy and click on a fragment (either Buick or Mazda), the layout of the fragment I clicked on is supposed to replace and cover the entire screen but the
container containing the list of cars stays on the screen and my fragment layout is shown below it. How can I make my fragment's layout replace the entire screen?
I couldn't post my AVD image showing the screen because I don't have enough reputatons to do
but the screen was showing as below when I clicked on the first item on the list.
Buick
Mazda
Hello! It's a Buick
my Mainactivity
package in.cars.demo;
import android.app.Activity;
import android.os.Bundle;
public class CarsMainActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
My ListFragment activity
package in.cars.demo;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.app.ListFragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class CarsList extends ListFragment {
String[] cars = new String[] { "Buick", "Mazda" };
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ListAdapter myListAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, cars);
setListAdapter(myListAdapter);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.cars_container, container, false);
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
Toast.makeText(getActivity(), getListView().getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
switch (position) {
case 0:
Fragment fragment1 = new Fragment1();
FragmentTransaction transaction1 = getFragmentManager().beginTransaction();
transaction1.replace(R.id.car_fragment, fragment1);
transaction1.addToBackStack(null);
transaction1.commit();
break;
case 1:
Fragment fragment2 = new Fragment2();
FragmentTransaction transaction2 = getFragmentManager().beginTransaction();
transaction2.replace(R.id.car_fragment, fragment2);
transaction2.addToBackStack(null);
transaction2.commit();
break;
}
}
}
Fragment1
package in.cars.demo;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment1 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment1, container, false);
}
}
Fragment2
package in.cars.demo;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment2 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment2, container, false);
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<fragment
android:id="#+id/car_fragment"
android:name="in.cars.demo.CarsList"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
cars_container.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="4dp"
android:paddingRight="4dp">
<ListView android:id="#id/android:list"
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1"/>
</LinearLayout>
fragment1.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/frag1TV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Hello! It's a Buick" />
</LinearLayout>
fragment2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/frag2TV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Hello! It's a Mazda" />
</LinearLayout>

The problem is that you set the layout_height of your fragment to wrap_content in your main.xml. The visible size will be reduced to the actual size of the fragment.
Change it to match_parent to fill the whole screen:
...
<fragment
android:id="#+id/car_fragment"
android:name="in.cars.demo.CarsList"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
...
Furthermore use match_parent instead of fill_parent in apps with API Level 8+. See this question for more information.
Edit:
You have to change the container for the Fragments. The Fragment set with the tag will be static. Every fragment will be set in addition to this container. To have a dynamic approach use a FrameLayout. Now you can replace the fragment which was in there before.
...
<FrameLayout
android:id="#+id/car_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
...
To show your CarsList you have to do a Fragment transaction in your Activity.
getFragmentManager() / getSupportFragmentManager()
.beginTransaction()
.replace(R.id.car_fragment, new CarsList())
.addToBackstack(null)
.commit();

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/white"
android:clickable="true"
android:orientation="vertical">
Try to setUp a color background to your fragment. In this way the background covers the entire space.

It is a little bit late, but maybe I will help someone else. The problem is with 'fragment' in your activity xml layout file (main.xml). You have to change:
<fragment
android:id="#+id/car_fragment"
android:name="in.cars.demo.CarsList"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
to
<fragment
android:id="#+id/car_fragment"
android:name="in.cars.demo.CarsList"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

Android fragment not created after runtime

I'm trying to add a fragment to an activity after the content view in the activity has been set. I'm not using the compatibility package and have my target API set to 16. I'm expecting the activity to be set to the fragments layout after the setContentView method in the main activity but on runtime, the fragment is never added and the screen in blank. The callbacks for the life cycle events in the fragment are never called thus the System.outs don't output. Logcat doesn't output any errors relating to fragments either. If a fragment element is made in the activity_main.xml, the fragment works fine but adding it to the RelativeLayout in the class doesn't work. Can someone please help me? Thanks!
Edit: Tried using a FrameLayout as the fragment_container but no difference.
This is my main activity:
package com.example.derp;
import android.os.Bundle;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Fragment frag = new Fragment();
FragmentManager fManager = getFragmentManager();
fManager.beginTransaction().add(R.id.fragment_container, frag).commit();
}
}
This is my fragment:
package com.example.derp;
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Frag extends Fragment{
public Frag(){
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
System.out.println("onAttach");
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
System.out.println("onCreate");
}
#Override
public void onStart() {
super.onStart();
System.out.println("onStart");
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
System.out.println("onCreateView");
return inflater.inflate(R.layout.fragment_frag, container, false);//
}
}
This is the fragment_frag.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Button" />
<EditText
android:id="#+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button1"
android:layout_centerHorizontal="true"
android:layout_marginBottom="64dp"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
</RelativeLayout>
The activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<RelativeLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
</RelativeLayout>
</RelativeLayout>

You are not creating the instance of your fragment class. Rather you are creating the base fragment class's object.
Change...
Fragment frag = new Fragment();
To...
Fragment frag = new Frag();