MainActivity.kt
package com.cfsuman.kotlinexamples
import android.Manifest
import android.content.Context
import android.graphics.Bitmap
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
import android.os.Build
import android.view.View
import android.app.DownloadManager
import android.content.pm.PackageManager
import android.net.Uri
import android.os.Environment
import android.webkit.*
import android.webkit.WebView
import android.view.ContextMenu
class MainActivity : AppCompatActivity() {
private val url = "https://www.google.com"
private val PermissionsRequestCode = 123
private lateinit var managePermissions: ManagePermissions
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Initialize a list of required permissions to request runtime
val list = listOf<String>(
Manifest.permission.WRITE_EXTERNAL_STORAGE
)
// Initialize a new instance of ManagePermissions class
managePermissions = ManagePermissions(this,list,PermissionsRequestCode)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) managePermissions.checkPermissions()
// Get the web view settings instance
val settings = web_view.settings
// Enable java script in web view
settings.javaScriptEnabled = true
// Register for context menu
registerForContextMenu(web_view)
// More optional settings
settings.domStorageEnabled = true
// Set web view client
web_view.webViewClient = object: WebViewClient(){
override fun onPageStarted(view: WebView, url: String, favicon: Bitmap?) {
// Page loading started
toast("Page loading.")
}
override fun onPageFinished(view: WebView, url: String) {
// Page loading finished
// Display the loaded page title in a toast message
toast("Page loaded: ${view.title}")
}
}
// Set web view chrome client
web_view.webChromeClient = object: WebChromeClient(){
override fun onProgressChanged(view: WebView, newProgress: Int) {
progress_bar.progress = newProgress
}
}
// Load button click listener
button_load.setOnClickListener{
// Load url in a web view
web_view.loadUrl(url)
}
}
// Method to download file from url
private fun download(imageUrl:String){
// Initialize download request
val request = DownloadManager.Request(Uri.parse(imageUrl))
// Set download request description
request.setDescription("Downloading requested image....")
// Allow scanning
request.allowScanningByMediaScanner()
// Download request notification setting
request.setNotificationVisibility(
DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
// Guess the file name
val fileName = URLUtil.guessFileName(imageUrl, null, null)
// Set a destination storage for downloaded file
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
// Set request title
request.setTitle("Image Download : $fileName")
// Get the system download service
val dManager = getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
// Finally, request the download to system download service
dManager.enqueue(request)
}
// To save image from web view
override fun onCreateContextMenu(menu: ContextMenu, v: View, menuInfo: ContextMenu.ContextMenuInfo?) {
super.onCreateContextMenu(menu, v, menuInfo)
// Get the web view hit test result
val result = web_view.hitTestResult
// If user long press on an image
if (
result.type == WebView.HitTestResult.IMAGE_TYPE ||
result.type == WebView.HitTestResult.SRC_IMAGE_ANCHOR_TYPE) {
// Set the title for context menu
menu.setHeaderTitle("CONTEXT MENU")
// Add an item to the menu
menu.add(
0,
1,
0,
"Save Image"
).setOnMenuItemClickListener({
// Get the image url
val imgUrl = result.extra
// If this is an image url then download it
if (URLUtil.isNetworkUrl(imgUrl)) {
if (managePermissions.isPermissionsGranted() == PackageManager.PERMISSION_GRANTED) {
download(imgUrl)
toast("Image saved.")
} else {
managePermissions.checkPermissions()
toast("Grant permission(s) & try again.")
}
} else {
toast("Invalid image url.")
}
false
})
}else{
toast("App can't handle target type.")
}
}
// Receive the permissions request result
override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>,
grantResults: IntArray) {
when (requestCode) {
PermissionsRequestCode ->{
val isPermissionsGranted = managePermissions
.processPermissionsResult(requestCode,permissions,grantResults)
if(isPermissionsGranted){
// Do the task now
toast("Permission(s) granted.")
}else{
toast("Permission(s) denied.")
}
return
}
}
}
// Handle back button press in web view
override fun onBackPressed() {
if (web_view.canGoBack()) {
// If web view have back history, then go to the web view back history
web_view.goBack()
toast("Going to back history")
} else {
super.onBackPressed()
}
}
}
// 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:background="#edfaed"
android:padding="0dp"
android:orientation="vertical"
>
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="@style/Widget.AppCompat.ProgressBar.Horizontal"
/>
<Button
android:id="@+id/button_load"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Load URL"
android:textAllCaps="false"
/>
<WebView
android:id="@+id/web_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
</LinearLayout>
ManagePermissions.kt
package com.cfsuman.kotlinexamples
import android.app.Activity
import android.content.pm.PackageManager
import android.support.v4.app.ActivityCompat
import android.support.v4.content.ContextCompat
import android.support.v7.app.AlertDialog
class ManagePermissions(private val activity: Activity,
private val list: List<String>,val code:Int
) {
// Check permissions at runtime
fun checkPermissions() {
if (isPermissionsGranted() != PackageManager.PERMISSION_GRANTED) {
showAlert()
} else {
activity.toast("Permission(s) already granted.")
}
}
// Check permissions status
fun isPermissionsGranted(): Int {
// PERMISSION_GRANTED : Constant Value: 0
// PERMISSION_DENIED : Constant Value: -1
var counter = 0;
for (permission in list) {
counter += ContextCompat.checkSelfPermission(activity, permission)
}
return counter
}
// Find the first denied permission
private fun deniedPermission(): String {
for (permission in list) {
if (ContextCompat.checkSelfPermission(activity, permission)
== PackageManager.PERMISSION_DENIED) return permission
}
return ""
}
// Show alert dialog to request permissions
private fun showAlert() {
val builder = AlertDialog.Builder(activity)
builder.setTitle("Need permission(s)")
builder.setMessage("Permission(s) required to do the task.")
builder.setPositiveButton("OK", { _, _ -> requestPermissions() })
builder.setNeutralButton("Cancel", null)
val dialog = builder.create()
dialog.show()
}
// Request the permissions at run time
private fun requestPermissions() {
val permission = deniedPermission()
if (ActivityCompat.shouldShowRequestPermissionRationale(activity, permission)) {
// Show an explanation asynchronously
activity.toast("Should show an explanation.")
} else {
ActivityCompat.requestPermissions(activity, list.toTypedArray(), code)
}
}
// Process permissions result
fun processPermissionsResult(requestCode: Int, permissions: Array<String>,
grantResults: IntArray): Boolean {
var result = 0
if (grantResults.isNotEmpty()) {
for (item in grantResults) {
result += item
}
}
if (result == PackageManager.PERMISSION_GRANTED) return true
return false
}
}
AndroidManifest.xml [Permissions]
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
- kotlin - Request permissions at runtime example
- kotlin - WebView example
- kotlin - WebView file download example
- kotlin - AlertDialog setItems example
- kotlin - AlertDialog yes no cancel button example
- kotlin - CountDownTimer start stop pause resume example
- kotlin - CountDownTimer days hours minutes seconds example
- kotlin - Save image to internal storage
- kotlin - Save image to external storage example
- kotlin - Compress bitmap example