android kotlin - Save image to Gallery example

MainActivity.kt

package com.cfsuman.kotlinexamples

import android.content.Context
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import android.provider.MediaStore
import android.graphics.drawable.BitmapDrawable
import android.net.Uri
import android.os.Build
import android.support.v4.content.ContextCompat
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

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

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
            // Check run time permission for write external storage
            // android.permission.WRITE_EXTERNAL_STORAGE
        }

        // Click listener for button widget
        button.setOnClickListener{
            // Disable the save button
            it.isEnabled = false

            // Save the image to gallery and get saved image Uri
            val uri = saveImage(R.drawable.flower,"Flower")
            toast("saved : $uri")

            // Show the saved image in an image view
            image_view_saved.setImageURI(uri)
        }
    }


    // Method to save an image to gallery and return uri
    private fun saveImage(drawable:Int, title:String):Uri{
        // Get the image from drawable resource as drawable object
        val drawable = ContextCompat.getDrawable(applicationContext,drawable)

        // Get the bitmap from drawable object
        val bitmap = (drawable as BitmapDrawable).bitmap

        // Save image to gallery
        val savedImageURL = MediaStore.Images.Media.insertImage(
                contentResolver,
                bitmap,
                title,
                "Image of $title"
        )

        // Parse the gallery image url to uri
        return Uri.parse(savedImageURL)
    }
}



// Extension function to show toast message
fun Context.toast(message: String) {
    Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/root_layout"
    android:background="#d1b7c6"
    android:padding="16dp"
    android:orientation="vertical"
    >
    <ImageView
        android:id="@+id/image_view_source"
        android:layout_width="match_parent"
        android:layout_height="250dp"
        android:src="@drawable/flower"
        />
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save"
        android:layout_gravity="center_horizontal"
        />
    <ImageView
        android:id="@+id/image_view_saved"
        android:layout_width="match_parent"
        android:layout_height="250dp"
        />
</LinearLayout>

AndroidManifest.xml [Permission]

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>