show error on vpn permission denial.

Author: Ginder-Singh

base/src/main/java/com/windscribe/vpn/alert/ForegroundAlert.kt

@@ -19,7 +19,7 @@ fun showRetryDialog(message: String, retryCallBack: () -> Unit, cancelCallBack:
             dialog.dismiss()
             if (which == AlertDialog.BUTTON_POSITIVE) {
                 retryCallBack()
-            }else if(which == AlertDialog.BUTTON_NEGATIVE){
+            } else if (which == AlertDialog.BUTTON_NEGATIVE) {
                 cancelCallBack()
             }
         }
@@ -110,12 +110,39 @@ fun showAlertDialog(
                 positionButtonLabel,
                 DialogInterface.OnClickListener(function = listener)
             )
-            setNegativeButton(negativeButtonLabel, DialogInterface.OnClickListener(function = listener))
+            setNegativeButton(
+                negativeButtonLabel,
+                DialogInterface.OnClickListener(function = listener)
+            )
             show()
         }
     }
 }
 
+fun showErrorDialog(activity: Activity, message: String, callBack: () -> Unit) {
+    val builder = createDialogBuilder(activity, message)
+    activity.let {
+        it.runOnUiThread {
+            builder.setOnDismissListener {
+                callBack()
+            }
+            builder.setOnCancelListener {
+                callBack()
+            }
+            val listener = { dialog: DialogInterface, _: Int ->
+                dialog.dismiss()
+            }
+            with(builder) {
+                setNeutralButton(
+                    appContext.getString(R.string.ok),
+                    DialogInterface.OnClickListener(function = listener)
+                )
+                show()
+            }
+        }
+    }
+}
+
 fun safeDialog(block: (activity: Activity) -> Unit) {
     appContext.activeActivity?.let {
         it.runOnUiThread {

base/src/main/java/com/windscribe/vpn/backend/utils/VPNPermissionActivity.kt

@@ -15,6 +15,8 @@ import android.os.Bundle
 import com.windscribe.vpn.R.layout
 import com.windscribe.vpn.Windscribe
 import com.windscribe.vpn.Windscribe.Companion.appContext
+import com.windscribe.vpn.alert.showAlertDialog
+import com.windscribe.vpn.alert.showErrorDialog
 import com.windscribe.vpn.autoconnection.ProtocolInformation
 import com.windscribe.vpn.backend.VpnBackendHolder
 import com.windscribe.vpn.repository.LocationRepository
@@ -121,9 +123,19 @@ class VPNPermissionActivity : Activity() {
                 }
             } else if (resultCode == RESULT_CANCELED) {
                 logger.debug("User denied VPN permission.")
-                scope.launch {
-                    vpnController.disconnectAsync()
-                    finish()
+                showErrorDialog(this,
+                    "Windscribe requires VPN permission to configure VPN. " +
+                            "Sometimes you may see this error if another VPN app is configured as 'Always on VPN'. " +
+                            "Please turn off 'Always on' in all profiles.") {
+                    scope.launch {
+                        try {
+                            vpnController.disconnectAsync()
+                        } catch (e: Exception) {
+                            logger.error("Failed to disconnect VPN: ${e.message}")
+                        } finally {
+                            finish()
+                        }
+                    }
                 }
             }
         }