How to implement Fragments in Android.
A fragment is a part or portion of Activity. It is also known as sub-activity.
The Primary classes related to fragment are:
- android.app.Fragment: Base class for fragment definitions.
- android.app.FragmentManager: Class for interacting with fragments within the activity.
- android.app.FragmentTransaction: Class for performing operations like adding or replacing the fragments.
Google also provides compatibility support v4 package for Fragments.Its main classes are :
- android.support.v4.app.FragmentActivity: The base class for all activity to containing fragment related features.
- android.support.v4.app.Fragment: The base class for all fragment operations.
- android.support.v4.app.FragmentManager: The class for interacting with fragments in activity.
- android.support.v4.app.FragmentTransaction: The class for performing fragments operations like adding,replacing the fragment.
Note: To use compatibility support v4 package your activity must use FragmentActivity as a Base Class.
if you are already familiar with fragments check Android Working with Fragments Part Two
Main Features of Fragment:-
- A Fragment has its own layout and lifecycle similar to Activity.
- A Fragment can be added or removed at runtime thus making UI look appropriate.
- There can many fragments in one activity.
- Fragment are reusable, Fragments must be embedded in activities.
So, Let’s by taking an example:
Steps:-
- Layout for fragment named as data_fragment.
- Create a Fragment named as DataFragment using above layout.
- Layout for fragment named as list_fragment.
- Create a Fragment named as Listing Fragment using above layout.
- Now create a layout for Activity named as activity_main containing above two Fragments we created.
- Now Create an Activity named as MainActivity and run the Project.
Open AndroidStudio or Eclipse and create an android application project and follow the instructions and then click on finish.
- First of all, we will create a layout for fragment as data_fragment
<?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:gravity="center"
android:background="#5ba4e5"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="40px"
android:textColor="#ffffff"
android:layout_gravity="center"
android:id="@+id/mainitems"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="#ffffff"
android:textSize="30px"
android:id="@+id/subitems"/>
</LinearLayout>
2. Create Fragment class DataFragment
package com.coderzpassion.fragmentssample;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
* Created by coderzpassion on 13/06/16.
*/
public class DataFragment extends Fragment {
TextView text,vers;
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.data_fragment, container, false);
text= (TextView) view.findViewById(R.id.mainitems);
vers= (TextView)view.findViewById(R.id.subitems);
return view;
}
public void change(String txt, String txt1){
text.setText(txt);
vers.setText(txt1);
}
}
3. Create a layout named as list_fragment
<?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">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/listfragment" />
</LinearLayout>
4. Create a Fragment named as ListingFragment
package com.coderzpassion.fragmentssample;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
/**
* Created by coderzpassion on 13/06/16.
*/
public class ListingFragment extends Fragment implements AdapterView.OnItemClickListener{
String[] MainItems = new String[] { "main item 1","main item 2","main item 3","main item 4","main item 5","main item 6","main item 7","main item 8","main item 9" };
String[] SubItems = new String[]{"sub item 1","sub item 2","sub item 3","sub item 4","sub item 5","sub item 6","sub item 7","sub item 8","sub item 9"};
ListView list;
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {
View view =inflater.inflate(R.layout.list_fragment, container, false);
list=(ListView)view.findViewById(R.id.listfragment);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, MainItems);
list.setAdapter(adapter);
list.setOnItemClickListener(this);
return view;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
DataFragment txt = (DataFragment)getFragmentManager().findFragmentById(R.id.fragment2);
txt.change(MainItems[position], "SubItems : " + SubItems[position]);
}
}
5. Create a layout named as activity_main
<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:orientation="horizontal"
android:weightSum="2"
>
<fragment
android:layout_height="match_parent"
android:layout_width="0dp"
android:layout_weight="1"
class="com.coderzpassion.fragmentssample.ListingFragment"
android:id="@+id/fragment"/>
<fragment
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
class="com.coderzpassion.fragmentssample.DataFragment"
android:id="@+id/fragment2"/>
</LinearLayout>
6. Create an Activity class named as default MainActivity.
package com.coderzpassion.fragmentssample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Now run this Project you will find the Output like this
