+ (NSString *)getIphoneXNetWorkStates {  UIApplication *app = [UIApplication sharedApplication]; id statusBar = [[app valueForKeyPath:@"statusBar"] valueForKeyPath:@"statusBar"]; id one = [statusBar valueForKeyPath:@"regions"]; id two = [one valueForKeyPath:@"trailing"]; NSArray *three = [two valueForKeyPath:@"displayItems"]; NSString *state = @"無網絡"; for (UIView *view in three) {  //alert: iOS12.0 情況下identifier的變成了類"_UIStatusBarIdentifier"而不是NSString，所以會在調用“isEqualToString”方法時發生crash，  //修改前//  NSString *identifier = [view valueForKeyPath:@"identifier"];  //修改后  NSString *identifier = [[view valueForKeyPath:@"identifier"] description];  if ([identifier isEqualToString:@"_UIStatusBarWifiItem.signalStrengthDisplayIdentifier"]) {   id item = [view valueForKeyPath:@"_item"];   //alert: 這個問題和上邊一樣itemId是_UIStatusBarIdentifier 類型，不是string   NSString *itemId = [[item valueForKeyPath:@"identifier"] description];   if ([itemId isEqualToString:@"_UIStatusBarWifiItem"]) {    state = @"WIFI";   }   state = @"不確定";  } else if ([identifier isEqualToString:@"_UIStatusBarCellularItem.typeDisplayIdentifier"]) {   UIView *statusBarStringView = [view valueForKeyPath:@"_view"];   // 4G/3G/E   state = [statusBarStringView valueForKeyPath:@"text"];  } } return state;}