You know that, in android, an activity has a lifecycle associated with them, activities receive their own input events. Like an activity, a fragment too has a lifecycle associated with them and receives its own input events. So, You can call a fragment a sub-activity. You can add a fragment to the activity or, remove a fragment from the activity during runtime. You can have multiple fragments in an activity.
There are two ways to add a fragment to an activity. One method is to add the fragment via XML and the second method is adding a fragment programmatically.
In this post, I will cover the first method of adding a fragment to an activity. I will cover the second method in my next post.
How to add fragments to activity in android?
First set up the project with an activity.
Now create a layout file for the fragment. Like this-
fragment_main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<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"
android:background="#5BDDE1"
tools:context=".MainActivityFragment">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Hi there! I'm a fragment"
android:textColor="#FAF6F6"
android:textSize="30sp" />
</FrameLayout>
This is a simple layout with a TextView inside a FrameLayout. We will inflate this layout inside a class that extends Fragment.
Now, create a class that extends Fragment and override its methods. Like this –
MainActivityFragment.java
package com.example.fragment_example;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MainActivityFragment extends Fragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_main_activity, container, false);
}
}
You inflate the layout for the fragment inside the onCreateView() method. This method returns the inflated layout. See the code above. I have inflated the layout that I created earlier inside the onCreateView() method.
Now, to add this fragment to the activity change the activity_main.xml file like this –
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<fragment
android:id="@+id/fragment"
android:name="com.example.fragment_example.MainActivityFragment"
android:layout_width="369dp"
android:layout_height="192dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
To add the fragment to an activity we use the <Fragment> element. Here android:name attribute is important because it specifies the class name of the Fragment to instantiate.
MainActivity.java
package com.example.fragment_example;
import androidx.appcompat.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);
}
}
Output:
That’s how you add a fragment to an activity.
DeveloperXon 
Leave a Reply