KotlinViewPager

http://thoughtnerds.com/viewpager-using-kotlin-android-tutorial/

ViewPager Using Kotlin Android Tutorial

ViewPager in Android allows the user to flip left and right through pages of data. In our android ViewPager application we’ll implement a ViewPager that swipes through three views. This tutorial to show how implement ViewPager Using Kotlin Android .

1. Create a Model enum for getting three view Model.kt

package com.cretlabs.viewpager

/**
 * Created by Gokul on 2/11/2018.
 */

enum class Model private constructor(val titleResId: Int, val layoutResId: Int) {
    RED(R.string.one, R.layout.layout_one),
    BLUE(R.string.two, R.layout.layout_two),
    GREEN(R.string.three, R.layout.layout_three)
}

2. Create a Pager adapter to inflate view CustomPagerAdapter.kt

package com.cretlabs.viewpager

/**
 * Created by Gokul on 2/11/2018.
 */
import android.content.Context
import android.support.v4.view.PagerAdapter
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class CustomPagerAdapter(private val mContext: Context) : PagerAdapter() {

    override fun instantiateItem(collection: ViewGroup, position: Int): Any {
        val modelObject = Model.values()[position]
        val inflater = LayoutInflater.from(mContext)
        val layout = inflater.inflate(modelObject.layoutResId, collection, false) as ViewGroup
        collection.addView(layout)
        return layout
    }

    override fun destroyItem(collection: ViewGroup, position: Int, view: Any) {
        collection.removeView(view as View)
    }

    override fun getCount(): Int {
        return Model.values().size
    }

    override fun isViewFromObject(view: View, `object`: Any): Boolean {
        return view === `object`
    }

    override fun getPageTitle(position: Int): CharSequence {
        val customPagerEnum = Model.values()[position]
        return mContext.getString(customPagerEnum.titleResId)
    }

}

3. Create layout_one.xml to infalte first view

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_gravity="center"
    android:layout_height="match_parent">

    <android.support.v7.widget.AppCompatTextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        style="@style/Base.TextAppearance.AppCompat.Subhead"
        android:text="@string/one" />
</android.support.constraint.ConstraintLayout>

4. Create layout_two.xml to inflate second view

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_gravity="center"
    android:layout_height="match_parent">
    <android.support.v7.widget.AppCompatTextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        style="@style/Base.TextAppearance.AppCompat.Subhead"
        android:text="@string/two" />
</android.support.constraint.ConstraintLayout>

5. Create layout_three.xml to inflate third view

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_gravity="center"
    android:layout_height="match_parent">

    <android.support.v7.widget.AppCompatTextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        style="@style/Base.TextAppearance.AppCompat.Subhead"
        android:text="@string/three" />
</android.support.constraint.ConstraintLayout>

6. Create a activity_main.xml contains viewpager

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.cretlabs.viewpager.MainActivity">

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

</android.support.constraint.ConstraintLayout>

7. Create MainActivity.Kt to initialize and setting adapter to Viewpager

package com.cretlabs.viewpager

import android.os.Bundle
import android.support.v4.view.ViewPager
import android.support.v7.app.AppCompatActivity
import android.view.View


class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main);
        val viewPager = findViewById<View>(R.id.viewpager) as ViewPager
        viewPager.adapter = CustomPagerAdapter(this)
    }
}