Improve Permission Handling and QR Code Import Logic in ScScannerActivity (#3777)

Refactored permission request handling in ScScannerActivity to improve readability and simplify the flow. Improved QR code import logic to ensure better handling of the scanned result and enhance user feedback.

V2rayNG/app/src/main/kotlin/com/v2ray/ang/ui/ScScannerActivity.kt

@@ -20,26 +20,31 @@ class ScScannerActivity : BaseActivity() {
     fun importQRcode(): Boolean {
         RxPermissions(this)
             .request(Manifest.permission.CAMERA)
-            .subscribe {
-                if (it)
+            .subscribe { granted ->
+                if (granted) {
                     scanQRCode.launch(Intent(this, ScannerActivity::class.java))
-                else
+                } else {
                     toast(R.string.toast_permission_denied)
+                }
             }
-
         return true
     }
 
+
     private val scanQRCode = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
         if (it.resultCode == RESULT_OK) {
-            val (count, countSub) = AngConfigManager.importBatchConfig(it.data?.getStringExtra("SCAN_RESULT"), "", false)
+            val scanResult = it.data?.getStringExtra("SCAN_RESULT").orEmpty()
+            val (count, countSub) = AngConfigManager.importBatchConfig(scanResult, "", false)
+
             if (count + countSub > 0) {
                 toast(R.string.toast_success)
             } else {
                 toast(R.string.toast_failure)
             }
+
             startActivity(Intent(this, MainActivity::class.java))
         }
         finish()
     }
+
 }