Creating Fragments in the simplest possible way-1

What are fragments?

Fragments in Android are like modular sections of a single activity having their own life-cycle.Umm..sort of sub-activity.

Fragments life cycle methods are affected by its host(Parent) life cycle.For ex:When parent activity is paused,so are all the fragments.When parent activity is destroyed,so are all the Fragment.When an activity is running,each of the fragments can be manipulated(Well i haven't tried it yet..:P)independently.

You can read more about fragments in 
http://developer.android.com/guide/components/fragments.html

Creating fragments

Like Activities,fragments also have their Life cycle callback methods.

To create a fragment you need to override at least its "onCreateView(Bundle)".This method has to return a view and that view is the root of your fragments layout.

Steps to create fragments

Step1:Create a layout XML file(simple_text_fragment.xml)

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<?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/textView1"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="TextView" />

    <TextView

    android:id="@+id/textView2"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="Large Text"

    android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

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Step 2:Create a class that extends Fragment and Override its onCreateView method

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public  class Example_fragment extends Fragment {

@Override

public void onAttach(Activity activity) {

super.onAttach(activity);

Log.v("Fragments","onAttach");

}

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

Log.v("Fragments","onCreate");

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

Log.v("Fragments","onCreateView");

                //1st Arg:Fragments Layout

               //2nd Arg:container(parent)

               //3rd Arg:Boolean arg indicating whether the fragment layout should be attached to       the viewGroup(2nd Arg).In our case,it is no as the system itself is doing it.

return inflater.inflate(R.layout.simple_text_fragment,container,false);

}

@Override

public void onStart() {

super.onStart();

Log.v("Fragments","onStart");

}

@Override

public void onResume() {

super.onResume();

Log.v("Fragments","onResume");

}

@Override

public void onPause() {

super.onPause();

Log.v("Fragments","onResume");

}

@Override

public void onStop() {

super.onStop();

Log.v("Fragments","onResume");

}

@Override

public void onDestroyView() {

super.onDestroyView();

}

@Override

public void onDestroy() {

super.onDestroy();

}

@Override

public void onDetach() {

super.onDetach();

}

}

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Step 3:

In you parent layout's XML file include the below snippet 

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    <fragment 

    android:name="com.example.apidemo.Example_fragment"

    android:id="@+id/myfragment"

                android:layout_width="wrap_content"

                android:layout_height="match_parent"

    />

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Step 4:

Create Root Activity that inflates parents layout XML.

That's it.Your activity should  look something similar like this

Happy Coding,

-Rajeev