Android RecyclerView With Item Divider

RecyclerView is a ViewGroup ,that display a scrolling list of elements based on large data sets (or data that frequently changes). RecyclerView widget is more flexible and efficient version of  ListView .

In the previous tutorial we have seen basic example of recyclerView and recyclerView item click , In this tutorial we will see how to add divider to item of recyclerView .



Project Detail
Project Name RecyclerView
Package com.tutorialsbuzz.recyclerview
Min Sdk Version 22
Target Sdk Version 29
Compile Sdk Version 29
Theme Theme.AppCompat.Light.DarkActionBar

Adding RecyclerView To Layout  



file : activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rcv"/>

Adapter and ViewHolder For RecyclerView .


1. XML Layout for RecyclerView Item : 

file : row_item.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:padding="20dp"
        android:layout_height="wrap_content">
    
    <TextView
            android:id="@+id/txt"
            android:textSize="22sp"
            android:text="Title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textStyle="bold"/>

    <TextView
            android:id="@+id/sub_txt"
            android:textSize="18sp"
            android:text="Title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textStyle="italic"/>

</LinearLayout>

2. Data class : 

We will read json file kept inside asset folder and map it data class .

find the data class at github code repo
https://github.com/TutorialsBuzz/RecyclerViewItemDivider/blob/master/app/src/main/java/com/tutorialsbuzz/recyclerview/Model.kt

3. Adapter and Viewholder :

find the Adapter and viewholder class at github code repo
https://github.com/TutorialsBuzz/RecyclerViewItemDivider/blob/master/app/src/main/java/com/tutorialsbuzz/recyclerview/CustomAdapter.kt

Divider For RecyclerView Items (ItemDecortion)


An ItemDecoration allows the application to add a special drawing and layout offset to specific item views from the adapter's data set. This can be useful for drawing dividers between items of recyclerView .

Create a rectangle shape drawable , set its width , height and set color .(This drawable is added between items of recyclerView)

file : line_divider.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle">
    <size
            android:width="1dp"
            android:height="1dp"/>

    <solid android:color="@color/dividerColor"/>

</shape>

Create a class SimpleDividerItemDecoration and extend it to ItemDecoration . Inside onDrawOver function draw the above defined drawable using canvas object .

file : SimpleDividerItemDecoration.kt
package com.tutorialsbuzz.recyclerview

import android.content.Context
import android.graphics.Canvas
import android.graphics.drawable.Drawable
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.RecyclerView

class SimpleDividerItemDecoration : RecyclerView.ItemDecoration {
    private var mDivider: Drawable? = null

    constructor(context: Context) {
        mDivider = ContextCompat.getDrawable(context, R.drawable.line_divider)
    }

    constructor(context: Context, drawable: Int) {
        mDivider = ContextCompat.getDrawable(context, drawable)
    }

    override fun onDrawOver(c: Canvas, recyclerView: RecyclerView, state: RecyclerView.State) {
        
        val left = recyclerView.paddingLeft
        val right = recyclerView.width

        val childCount = recyclerView.childCount
        for (i in 0 until childCount) {

            val child = recyclerView.getChildAt(i)
            val params = child.layoutParams as RecyclerView.LayoutParams
            val top = child.bottom + params.bottomMargin
            val bottom = top + mDivider!!.intrinsicHeight
            mDivider!!.setBounds(left, top, right, bottom)
            mDivider!!.draw(c)

        }
    }
}

 Adding CustomItemDecortion to recyclerView .

To add ItemDecorator call addItemDecoration using recyclerView reference and pass the instance of above defined SimpleDividerItemDecoration

rcv.addItemDecoration(SimpleDividerItemDecoration(this))

Activity


  1. Create a koltin class MainActivity.kt and extend it to AppCompatActivity class .
  2. Override onCreate function and set the content of this MainActivity with above defined xml layout (activity_main.xml). 
  3. Read JSON Data From Asset Folder , this will be used for binding data into recyclerView .
  4. Set Vertical Linear LayoutManager to RecyclerView.
  5. Create Instance of Adapter and set to RecyclerView .
  6. Add CustomItemDecortion to RecyclerView .

file : MainActivity.kt
package com.tutorialsbuzz.recyclerview

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.activity_main.*
import org.json.JSONArray
import org.json.JSONObject

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val model = readFromAsset();
        val adapter = CustomAdapter(model, this)
        rcv.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)
        rcv.adapter = adapter;
        rcv.addItemDecoration(SimpleDividerItemDecoration(this))
    }


    private fun readFromAsset(): List<Model> {
        val modeList = mutableListOf<Model>()
        val bufferReader = application.assets.open("android_version.json").bufferedReader()
        val json_string = bufferReader.use {
            it.readText()
        }

        val jsonArray = JSONArray(json_string);
        for (i in 0..jsonArray.length() - 1) {
            val jsonObject: JSONObject = jsonArray.getJSONObject(i)
            val model = Model(jsonObject.getString("name"), jsonObject.getString("version"))
            modeList.add(model)
        }
        return modeList
    }

}



RecyclerView Related
  1. RecyclerView
  2. RecyclerView Item Click Ripple Effect
  3. RecyclerView With Item Divider
  4. RecyclerView With CardView
  5. RecyclerView GridLayout
  6. RecyclerView StaggeredGrid Layout
  7. RecyclerView Swipe To Delete
  8. Android RecyclerView Swipe to Delete Undo
  9. Android RecyclerView Interactive Swipe Like Gmail

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