Skip to main content

android kotlin - WebView file download example






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.net.Uri
import android.os.Environment
import android.webkit.*


class MainActivity : AppCompatActivity() {
    private val url = "https://en.savefrom.net/"
    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

        // Enable and setup web view cache
        settings.setAppCacheEnabled(true)
        settings.cacheMode = WebSettings.LOAD_DEFAULT
        settings.setAppCachePath(cacheDir.path)


        // Enable zooming in web view
        settings.setSupportZoom(true)
        settings.builtInZoomControls = true
        settings.displayZoomControls = true


        // Zoom web view text
        settings.textZoom = 125


        // Enable disable images in web view
        settings.blockNetworkImage = false
        // Whether the WebView should load image resources
        settings.loadsImagesAutomatically = true


        // More web view settings
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            settings.safeBrowsingEnabled = true  // api 26
        }
        //settings.pluginState = WebSettings.PluginState.ON
        settings.useWideViewPort = true
        settings.loadWithOverviewMode = true
        settings.javaScriptCanOpenWindowsAutomatically = true
        settings.mediaPlaybackRequiresUserGesture = false


        // More optional settings, you can enable it by yourself
        settings.domStorageEnabled = true
        settings.setSupportMultipleWindows(true)
        settings.loadWithOverviewMode = true
        settings.allowContentAccess = true
        settings.setGeolocationEnabled(true)
        settings.allowUniversalAccessFromFileURLs = true
        settings.allowFileAccess = true

        // WebView settings
        web_view.fitsSystemWindows = true


        /*
            if SDK version is greater of 19 then activate hardware acceleration
            otherwise activate software acceleration
        */
        web_view.setLayerType(View.LAYER_TYPE_HARDWARE, null)


        // Set web view client
        web_view.webViewClient = object: WebViewClient(){
            override fun onPageStarted(view: WebView, url: String, favicon: Bitmap?) {
                // Page loading started
                // Do something
                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
            }
        }


        // Set web view download listener

        web_view.setDownloadListener(DownloadListener {
            url,
            userAgent,
            contentDescription,
            mimetype,
            contentLength ->

            // Initialize download request
            val request = DownloadManager.Request(Uri.parse(url))

            // Get the cookie
            val cookies = CookieManager.getInstance().getCookie(url)

            // Add the download request header
            request.addRequestHeader("Cookie",cookies)
            request.addRequestHeader("User-Agent",userAgent)

            // Set download request description
            request.setDescription("Downloading requested file....")

            // Set download request mime tytpe
            request.setMimeType(mimetype)

            // Allow scanning
            request.allowScanningByMediaScanner()

            // Download request notification setting
            request.setNotificationVisibility(
                    DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)

            // Guess the file name
            val fileName = URLUtil.guessFileName(url, contentDescription, mimetype)

            // Set a destination storage for downloaded file
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)

            // Set request title
            request.setTitle(URLUtil.guessFileName(url, contentDescription, mimetype));


            // DownloadManager request more settings
            request.setAllowedOverMetered(true)
            request.setAllowedOverRoaming(false)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                request.setRequiresCharging(false)
                request.setRequiresDeviceIdle(false)
            }
            request.setVisibleInDownloadsUi(true)


            // Get the system download service
            val dManager = getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager

            // Finally, request the download to system download service
            dManager.enqueue(request)
        })


        // Load button click listener
        button_load.setOnClickListener{
            // Load url in a web view
            web_view.loadUrl(url)
        }

    }



    // 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
    private 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"/>










Labels:

Popular posts from this blog

Restricting Jetpack Compose TextField to Numeric Input Only

Jetpack Compose has revolutionized Android development with its declarative approach, enabling developers to build modern, responsive UIs more efficiently. Among the many components provided by Compose, TextField is a critical building block for user input. However, ensuring that a TextField accepts only numeric input can pose challenges, especially when considering edge cases like empty fields, invalid characters, or localization nuances. In this blog post, we'll explore how to restrict a Jetpack Compose TextField to numeric input only, discussing both basic and advanced implementations. Why Restricting Input Matters Restricting user input to numeric values is a common requirement in apps dealing with forms, payment entries, age verifications, or any data where only numbers are valid. Properly validating input at the UI level enhances user experience, reduces backend validation overhead, and minimizes errors during data processing. Compose provides the flexibility to implement ...
Read more

jetpack compose - TextField remove underline

Compose TextField Remove Underline The TextField is the text input widget of android jetpack compose library. TextField is an equivalent widget of the android view system’s EditText widget. TextField is used to enter and modify text. The following jetpack compose tutorial will demonstrate to us how we can remove (actually hide) the underline from a TextField widget in an android application. We have to apply a simple trick to remove (hide) the underline from the TextField. The TextField constructor’s ‘colors’ argument allows us to set or change colors for TextField’s various components such as text color, cursor color, label color, error color, background color, focused and unfocused indicator color, etc. Jetpack developers can pass a TextFieldDefaults.textFieldColors() function with arguments value for the TextField ‘colors’ argument. There are many arguments for this ‘TextFieldDefaults.textFieldColors()’function such as textColor, disabledTextColor, backgroundColor, cursorC...
Read more

jetpack compose - Image clickable

Compose Image Clickable The Image widget allows android developers to display an image object to the app user interface using the jetpack compose library. Android app developers can show image objects to the Image widget from various sources such as painter resources, vector resources, bitmap, etc. Image is a very essential component of the jetpack compose library. Android app developers can change many properties of an Image widget by its modifiers such as size, shape, etc. We also can specify the Image object scaling algorithm, content description, etc. But how can we set a click event to an Image widget in a jetpack compose application? There is no built-in property/parameter/argument to set up an onClick event directly to the Image widget. This android application development tutorial will demonstrate to us how we can add a click event to the Image widget and make it clickable. Click event of a widget allow app users to execute a task such as showing a toast message by cli...
Read more