MainActivity.kt
package com.example.jetpack
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.os.Bundle
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.*
import java.io.IOException
import java.net.URL
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// url of image
val urlImage:URL = URL("https://images.pexels.com/photos/4017653/" +
"pexels-photo-4017653.jpeg?" +
"auto=compress&cs=tinysrgb&dpr=3&h=750&w=1260")
button.setOnClickListener {
it.isEnabled = false // disable button
progressBar.visibility = View.VISIBLE
// async task to get bitmap from url
val result: Deferred<Bitmap?> = lifecycleScope.async(Dispatchers.IO) {
urlImage.toBitmap
}
lifecycleScope.launch(Dispatchers.Main) {
// show bitmap on image view when available
imageView.setImageBitmap(result.await())
it.isEnabled = true // enable button
progressBar.visibility = View.INVISIBLE
}
}
}
}
// extension property to get bitmap from url
val URL.toBitmap:Bitmap?
get() {
return try {
BitmapFactory.decodeStream(openStream())
}catch (e: IOException){null}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:id="@+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#EDEAE0"
tools:context=".MainActivity">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:backgroundTint="#2E2D88"
android:text="Show Image"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:visibility="invisible"
app:layout_constraintBottom_toBottomOf="@+id/button"
app:layout_constraintStart_toEndOf="@+id/button"
app:layout_constraintTop_toTopOf="@+id/button" />
<ImageView
android:id="@+id/imageView"
android:layout_width="0dp"
android:layout_height="300dp"
android:layout_marginTop="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button"
tools:srcCompat="@tools:sample/avatars" />
</androidx.constraintlayout.widget.ConstraintLayout>
build.gradle(app) [dependencies to add]
// kotlin coroutines
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9'
// life cycle
def lifecycle_version = "2.2.0"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"

- android kotlin - Switch button listener
- android kotlin - Material switch button
- android kotlin - Create ImageView programmatically
- android kotlin - ImageView rounded corners transparent
- android kotlin - ImageView circle crop
- android kotlin - ImageView set image from assets
- android kotlin - ImageView border shadow
- android kotlin - ImageView border radius
- android kotlin - ImageView tint programmatically
- android kotlin - ImageView rounded top corners programmatically
- android kotlin - ImageView rounded corners programmatically
- android kotlin - Get battery capacity programmatically
- android kotlin - Get battery percentage programmatically
- android kotlin - Get battery level programmatically
- android kotlin - Get battery voltage programmatically