fix:修复部分等级URL解析失败问题

app/src/main/java/com/nnbc123/app/support/LevelIconHelper.kt

@@ -73,12 +73,27 @@ object LevelIconHelper : ILog {
             return null
         }
         // https://image.nnbc123.cn/charm_20.png
-        val dotIndex = levelIconUrl.lastIndexOf('.')
-        val separatorIndex = levelIconUrl.lastIndexOf('_') + 1
-        if (dotIndex > 0 && separatorIndex > 0 && dotIndex > separatorIndex) {
-            return levelIconUrl.substring(separatorIndex, dotIndex).toIntOrNull()
+        // https://image.nnbc123.cn/charm_20_1.png
+        val separatorIndex = levelIconUrl.lastIndexOf('/')
+        if (separatorIndex == -1) {
+            return null
         }
-        return null
+        var numberStart = levelIconUrl.indexOf('_', startIndex = separatorIndex)
+        if (numberStart == -1) {
+            return null
+        }
+        numberStart++
+        if (numberStart >= levelIconUrl.length) {
+            return null
+        }
+        var numberEnd = levelIconUrl.indexOf('_', startIndex = numberStart)
+        if (numberEnd == -1) {
+            numberEnd = levelIconUrl.indexOf('.', startIndex = numberStart)
+        }
+        if (numberEnd == -1) {
+            return null
+        }
+        return levelIconUrl.substring(numberStart, numberEnd).toIntOrNull()
     }
 
     private fun getLevelName(level: Int?): String? {