View Pager Example in Android Studio

1. What is ViewPager?
Ans:-Layout manager that allows the user to flip left and right through pages of data. You supply an implementation of a PagerAdapter to generate the pages that the view shows. ViewPager is most often used in conjunction with Fragment , which is a convenient way to supply and manage the lifecycle of each page.

Here we will see how to implement ViewPager in Android Application.For this Example we will create 3 Layouts and their JAVA class and add these Layouts to MainActivity.java.Following are the site map.
1.MainActiviry.java  | activity_main.xml
2.ViewPager1.java  | view_pager1.xml
3.ViewPager2.java  | view_pager2.xml
4.ViewPager3.java  | view_pager3.xml

Step 1:- main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context="supriya.com.viewpagerexample.MainActivity">

    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/vPager">
</android.support.v4.view.ViewPager>
</RelativeLayout>

Step 2:- MainActivity.java

package supriya.com.viewpagerexample;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    ViewPager vpager;

    @Override    

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        vpager=(ViewPager)findViewById(R.id.vPager);
        vpager.setAdapter(new setViewadapter(getSupportFragmentManager()));
    }
    public class setViewadapter extends FragmentPagerAdapter {
        public setViewadapter(FragmentManager fm) {
            super(fm);
        }
        @Override        

public Fragment getItem(int position) {
            if(position==0) {
                return new ViewPage1();
            }
            else if (position==1){
                return  new ViewPage2();
            }
            else                

                 return new ViewPage3();
        }

        @Override        

public int getCount() {
            return 3;
        }
    }
}

Step 3:- view_page1.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:gravity="center_vertical"
    android:background="#3ADF00">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ViewPage1"
        android:textSize="25sp"
        android:textAlignment="center"
        android:textColor="#ffffff"/>

</LinearLayout>
Step 4:- ViewPage1.java

package supriya.com.viewpagerexample;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/** * Created by Supriya on 9/11/2016. */

public class ViewPage1 extends Fragment {
    @Nullable    @Override    

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, 

@Nullable Bundle savedInstanceState) {
        View v=inflater.inflate(R.layout.view_page1,null);
        return v;
    }
}

Step 5:- view_page2.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:gravity="center_vertical"
    android:background="#B4045F">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ViewPage2"
        android:textSize="25sp"
        android:textAlignment="center"
        android:textColor="#ffffff"/>

</LinearLayout>
Step 6:- ViewPage2.java

package supriya.com.viewpagerexample;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/** * Created by Supriya on 9/11/2016. */

public class ViewPage2 extends Fragment {
    @Nullable    @Override   

 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v=inflater.inflate(R.layout.view_page2,null);
        return v;
    }
}

Step 7:- view_page3.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:gravity="center_vertical"
    android:background="#0174DF">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ViewPage3"
        android:textSize="25sp"
        android:textAlignment="center"
        android:textColor="#ffffff"/>


</LinearLayout>
Step 8:- ViewPage3.java

package supriya.com.viewpagerexample;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/** * Created by Supriya on 9/11/2016. */
public class ViewPage3 extends Fragment {
    @Nullable    @Override    
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v=inflater.inflate(R.layout.view_page3,null);
        return v;
    }
}