Day47 of #100DaysOfCode

#CodeTogether Day 47/100

Hii folks 🙌

Today I will be continuing the third pathway of UNIT 2 of Android Basics with Kotlin.

Unit 2: Layouts

Pathway 3: Display a scrollable list

Source: https://developer.android.com/courses/android-basics-kotlin/course

Use RecyclerView to display a scrollable list

Firstly, we will start by creating a new empty activity project.

  • Now, we will add the affirmation strings to the app in the strings.xml file.
<resources>    <string name="app_name">Affirmations</string>    <string name="affirmation1">I am strong.</string>    <string name="affirmation2">I believe in myself.</string></resources>
  • Now that we have added string resources, we can reference them in our code as R.string.affirmation1 or R.string.affirmation2.
  • Moving forward we will create a new package named model in the affirmation app. Under that create a class Affirmation.kt
package com.example.affirmations.model

data class Affirmation(val stringResourceId: Int)
  • Added a val integer parameter stringResourceId to the constructor of the Affirmation class.
  • Now we will create a class to be a data source, and under that, we will create a function called loadAffirmation() and will add the Affirmation objects to the list.
package com.example.affirmations.data

import com.example.affirmations.R
import com.example.affirmations.model.Affirmation


class Datasource {

fun loadAffirmations(): List<Affirmation> {
return listOf<Affirmation>(
Affirmation(R.string.affirmation1),
Affirmation(R.string.affirmation2),
Affirmation(R.string.affirmation3),
Affirmation(R.string.affirmation4),
Affirmation(R.string.affirmation5),
Affirmation(R.string.affirmation6),
Affirmation(R.string.affirmation7),
Affirmation(R.string.affirmation8),
Affirmation(R.string.affirmation9),
Affirmation(R.string.affirmation10)
)
}
}
  • Then we will add the RecycleView to our app.
package com.example.affirmations

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.RecyclerView
import com.example.affirmations.adapter.ItemAdapter
import com.example.affirmations.data.Datasource

class MainActivity : AppCompatActivity() {

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

// Initialize data.
val myDataset = Datasource().loadAffirmations()

val recyclerView = findViewById<RecyclerView>(R.id.recycler_view)
recyclerView.adapter = ItemAdapter(this, myDataset)

// Use this setting to improve performance if you know that changes
// in content do not change the layout size of the
RecyclerView
recyclerView.setHasFixedSize(true)
}
}

Then we will run the app and it will look like this:

Affirmations

Today I Learned:

  • RecyclerView widget helps us to display a list of data.
  • RecyclerView uses the adapter pattern to adapt and display the data.
  • ViewHolder creates and holds the views for RecyclerView.
  • RecyclerView comes with built-in LayoutManagers. RecyclerView delegates how items are laid out to LayoutManagers.

That is all for Day47 ✅

Thanks for reading, See you tomorrow!

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