Refactor extension functions for better performance and clarity (#3394)

Refactor Kotlin extension functions for clarity and performance

- Updated `v2RayApplication` extension to handle potential ClassCastException.
- Simplified `toast` functions for better readability.
- Refactored `toTrafficString` function to reduce redundancy and improve performance.
- Minor improvements to JSON and URL connection handling.

V2rayNG/app/src/main/kotlin/com/v2ray/ang/extension/_Ext.kt

@@ -9,15 +9,15 @@ import org.json.JSONObject
 import java.net.URI
 import java.net.URLConnection
 
-val Context.v2RayApplication: AngApplication
-    get() = applicationContext as AngApplication
+val Context.v2RayApplication: AngApplication?
+    get() = applicationContext as? AngApplication
 
 fun Context.toast(message: Int) {
-    ToastCompat.makeText(this, message, Toast.LENGTH_SHORT).apply { show() }
+    ToastCompat.makeText(this, message, Toast.LENGTH_SHORT).show()
 }
 
 fun Context.toast(message: CharSequence) {
-    ToastCompat.makeText(this, message, Toast.LENGTH_SHORT).apply { show() }
+    ToastCompat.makeText(this, message, Toast.LENGTH_SHORT).show()
 }
 
 fun JSONObject.putOpt(pair: Pair<String, Any?>) {
@@ -34,26 +34,14 @@ const val DIVISOR = 1024.0
 fun Long.toSpeedString(): String = this.toTrafficString() + "/s"
 
 fun Long.toTrafficString(): String {
-    if (this < THRESHOLD) {
-        return "$this B"
+    val units = arrayOf("B", "KB", "MB", "GB", "TB", "PB")
+    var size = this.toDouble()
+    var unitIndex = 0
+    while (size >= THRESHOLD && unitIndex < units.size - 1) {
+        size /= DIVISOR
+        unitIndex++
     }
-    val kb = this / DIVISOR
-    if (kb < THRESHOLD) {
-        return "${String.format("%.1f KB", kb)}"
-    }
-    val mb = kb / DIVISOR
-    if (mb < THRESHOLD) {
-        return "${String.format("%.1f MB", mb)}"
-    }
-    val gb = mb / DIVISOR
-    if (gb < THRESHOLD) {
-        return "${String.format("%.1f GB", gb)}"
-    }
-    val tb = gb / DIVISOR
-    if (tb < THRESHOLD) {
-        return "${String.format("%.1f TB", tb)}"
-    }
-    return String.format("%.1f PB", tb / DIVISOR)
+    return String.format("%.1f %s", size, units[unitIndex])
 }
 
 val URLConnection.responseLength: Long