解决方法
Swift标准库中有方法:
func print<Target>(_ items: Any...,separator: String = default,terminator: String = default,to output: inout Target) where Target : TextOutputStream
和
func debugPrint<Target>(_ items: Any...,to output: inout Target) where Target : TextOutputStream
您可以创建一个实现TextOutputStream的对象,该对象将消息保存到您选择的文件中.如果您已在代码库中已有现有打印件,则此功能非常有用.然后,您只需将附加参数添加到它们即可.请记住,这些打印将停止记录到标准输出(控制台).
例:
final class LogDestination: TextOutputStream { private let path: String init() { let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask,true) path = paths.first! + "/log" } func write(_ string: String) { if let data = string.data(using: .utf8),let fileHandle = FileHandle(forWritingAtPath: path) { defer { fileHandle.closeFile() } fileHandle.seekToEndOfFile() fileHandle.write(data) } } }
然后
// I would probably use Singleton for this var dest = LogDestination() print("My test message",to: &dest)