新浪天气预报api 城市编码 ios

NSString* city = @"天津";
 
    
NSStringEncoding chineseEncoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    
    
city = [city stringByAddingPercentEscapesUsingEncoding:chineseEncoding];

NSString* str = [NSString stringWithFormat:@"http://php.weather.sina.com.cn/xml.php?city=%@&password=DJOYnieT8234jlsK&day=0",city];