Fragment Example in Android

 Fragment Example in Android:-

The fragment is a predefined class in android, if we want to divide the screen into multipart and subpart then we can use Fragment class.

When we add a fragment then it will create a fragment class file and XML file.

Fragment class will load under activity and a design file is used to design the user interface using Fragment.

Example of Fragment using <fragment> tag:-

package com.example.customdrawer;

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);
    }
}

package com.example.customdrawer;

import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link SecondFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class SecondFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public SecondFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment SecondFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static SecondFragment newInstance(String param1, String param2) {
        SecondFragment fragment = new SecondFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_second, container, false);
    }
}



package com.example.customdrawer;

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);
    }
}



Example2 of Fragment:-

I am explaining to call Fragment class using Button Click.

package com.example.customdrawer;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity2 extends AppCompatActivity {

    Button btnone;
    Button btntwo;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        btnone = findViewById(R.id.btnfrg1);
        btntwo = findViewById(R.id.btnfrg2);
        btnone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
          getSupportFragmentManager().beginTransaction().replace(R.id.frgcontainer,new FirstFragment()).commit();
            }
        });

        btntwo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getSupportFragmentManager().beginTransaction().replace(R.id.frgcontainer,new SecondFragment()).commit();
            }
        });
    }
}


<?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="#03A9F4"
    tools:context=".FirstFragment">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />

</FrameLayout>

<?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="#C81515"
    tools:context=".SecondFragment">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />

</FrameLayout>


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="horizontal"
    android:background="#009688"
    tools:context=".MainActivity2">

    <LinearLayout
        android:layout_width="wrap_content"
        android:orientation="vertical"
        android:layout_height="match_parent"
        android:background="#2196F3"
        >

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnfrg1"
            android:text="First"
            ></Button>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnfrg2"
            android:text="Second"
            ></Button>
    </LinearLayout>

    <FrameLayout
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:id="@+id/frgcontainer"
        android:background="#009688"
        >

    </FrameLayout>
</LinearLayout>

How to write Java Code on Fragment:-

We should always write code on onCreateView() 

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View v= inflater.inflate(R.layout.fragment_first, container, false);
    btn = v.findViewById(R.id.btnfragmentclick);
    txtv = v.findViewById(R.id.txtres3);
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            txtv.setText("Welcome in Fragment");
        }
    });
    return v;
}


Code for Design View:-
<?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:background="#03A9F4"
    android:orientation="vertical"
    tools:context=".FirstFragment">

    <!-- TODO: Update blank fragment layout -->

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btnfragmentclick"
        android:text="CLICK"
        >

    </Button>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        android:id="@+id/txtres3"

        />

</LinearLayout>