feat: Implement Kiosk Mode and Runtime Permissions

app/src/main/AndroidManifest.xml

@@ -13,7 +13,8 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".MainActivity">
+        <activity android:name=".MainActivity"
+            android:lockTaskMode="if_whitelisted">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/imrankst1221/website/in/webview/MainActivity.kt

@@ -1,9 +1,11 @@
 package imrankst1221.website.`in`.webview
 
 import android.annotation.SuppressLint
+import android.Manifest
 import android.app.Activity
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.graphics.Bitmap
 import android.net.ConnectivityManager
 import android.net.NetworkInfo
@@ -24,6 +26,8 @@ import android.widget.RelativeLayout
 import android.widget.Toast
 import androidx.annotation.RequiresApi
 import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
 import java.io.File
 import java.io.IOException
 import java.io.UnsupportedEncodingException
@@ -37,6 +41,7 @@ import java.text.SimpleDateFormat
 import java.util.*
 import javax.crypto.*
 import javax.crypto.spec.SecretKeySpec
+import kotlin.collections.HashMap
 
 class MainActivity : Activity() {
     private lateinit var mContext: Context
@@ -64,11 +69,22 @@ class MainActivity : Activity() {
     @SuppressLint("SetJavaScriptEnabled")
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        window.decorView.systemUiVisibility = (View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+                // Set content to appear behind the system bars so that the
+                // content doesn't resize when the system bars hide and show.
+                or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
+                or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
+                or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+                // Hide the nav bar and status bar
+                or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
+                or View.SYSTEM_UI_FLAG_FULLSCREEN)
         setContentView(R.layout.activity_main)
 
         AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)
 
         mContext = this
+
+        checkAndRequestPermissions()
         mWebView = findViewById<View>(R.id.webview) as WebView
         prgs = findViewById<View>(R.id.progressBar) as ProgressBar
         btnTryAgain = findViewById<View>(R.id.btn_try_again) as Button
@@ -376,25 +392,82 @@ class MainActivity : Activity() {
     }
 
     override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
-        if (keyCode == KeyEvent.KEYCODE_BACK && mWebView.canGoBack()) {
-            mWebView.goBack()
+        if (keyCode == KeyEvent.KEYCODE_BACK) {
+            if (mWebView.canGoBack()) {
+                mWebView.goBack()
+            }
+            // Consume the event to prevent closing the app
+            return true
+        } else if (keyCode == KeyEvent.KEYCODE_APP_SWITCH) {
+            // Attempt to consume the app switch key event
             return true
         }
+        return super.onKeyDown(keyCode, event)
+    }
 
-        if (doubleBackToExitPressedOnce) {
-            return super.onKeyDown(keyCode, event)
+    override fun onBackPressed() {
+        if (mWebView.canGoBack()) {
+            mWebView.goBack()
         }
+        // If WebView cannot go back, do nothing (consume the event)
+    }
+
+    private fun checkAndRequestPermissions() {
+        val writePermission = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
+        val readPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
 
-        this.doubleBackToExitPressedOnce = true
-        Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show()
+        val listPermissionsNeeded = ArrayList<String>()
+        if (writePermission != PackageManager.PERMISSION_GRANTED) {
+            listPermissionsNeeded.add(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+        }
+        if (readPermission != PackageManager.PERMISSION_GRANTED) {
+            listPermissionsNeeded.add(Manifest.permission.READ_EXTERNAL_STORAGE)
+        }
 
-        Handler().postDelayed({ doubleBackToExitPressedOnce = false }, 2000)
-        return true
+        if (listPermissionsNeeded.isNotEmpty()) {
+            ActivityCompat.requestPermissions(this, listPermissionsNeeded.toTypedArray(), STORAGE_PERMISSION_CODE)
+        } else {
+            // Permissions are already granted. You can proceed with operations that need these permissions.
+            // For example, initialize WebView loading here if it depends on storage, though unlikely for just viewing.
+        }
+    }
+
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        if (requestCode == STORAGE_PERMISSION_CODE) {
+            val perms: MutableMap<String, Int> = HashMap()
+            // Initialize the map with permissions
+            perms[Manifest.permission.WRITE_EXTERNAL_STORAGE] = PackageManager.PERMISSION_GRANTED
+            perms[Manifest.permission.READ_EXTERNAL_STORAGE] = PackageManager.PERMISSION_GRANTED
+
+            // Fill with actual results from user
+            if (grantResults.isNotEmpty()) {
+                for (i in permissions.indices) {
+                    perms[permissions[i]] = grantResults[i]
+                }
+                // Check for both permissions
+                if (perms[Manifest.permission.WRITE_EXTERNAL_STORAGE] == PackageManager.PERMISSION_GRANTED &&
+                    perms[Manifest.permission.READ_EXTERNAL_STORAGE] == PackageManager.PERMISSION_GRANTED) {
+                    Log.d(TAG, "Storage permissions granted")
+                    // Permissions granted, proceed with app functionality or re-initialize parts that depend on it
+                    // If webview loading was deferred, you might trigger it here or a part of it.
+                    // For now, just logging is fine.
+                } else {
+                    Log.d(TAG, "Some permissions were denied")
+                    // Permissions were denied. Explain to the user the importance of these permissions
+                    // and potentially offer to request them again or disable functionality.
+                    Toast.makeText(this, "Storage Permissions are required for file uploads and downloads. Please enable them in app settings.", Toast.LENGTH_LONG).show()
+                    // Optionally, you could finish the activity or disable parts of the app
+                    // finish() 
+                }
+            }
+        }
     }
 
     companion object {
         internal var TAG = "---MainActivity"
         val INPUT_FILE_REQUEST_CODE = 1
+        private const val STORAGE_PERMISSION_CODE = 101
         val EXTRA_FROM_NOTIFICATION = "EXTRA_FROM_NOTIFICATION"