Question

是否可以将每个NSLog写入控制台，但也可以写入文件？我想在不将NSLog替换为someExternalFunctionForLogging的情况下进行准备。

替换所有NSLog将是真正的问题。也许有可能从控制台解析数据或捕获消息？

Answer 1

选项1：使用ASL

NSLog将日志输出到ASL（Apple的syslog版本）和控制台，这意味着当您使用iPhone模拟器时，它已经写入Mac中的文件。如果要读取它，请打开应用程序Console.app，然后在过滤器字段中键入应用程序的名称。要在iPhone设备中执行相同操作，您需要使用ASL API并进行一些编码。

选项2：写入文件

假设您正在模拟器上运行，并且您不想使用Console.app。您可以使用freopen将错误流重定向到您喜欢的文件：
freopen([path cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);
有关详细信息，请参阅此explanation and sample project。

或者您可以使用宏来使用自定义函数覆盖NSLog。例如，将此类添加到项目中：

// file Log.h
#define NSLog(args...) _Log(@"DEBUG ", __FILE__,__LINE__,__PRETTY_FUNCTION__,args);
@interface Log : NSObject
void _Log(NSString *prefix, const char *file, int lineNumber, const char *funcName, NSString *format,...);
@end

// file Log.m
#import "Log.h"
@implementation Log
void _Log(NSString *prefix, const char *file, int lineNumber, const char *funcName, NSString *format,...) {
    va_list ap;
    va_start (ap, format);
    format = [format stringByAppendingString:@"\n"];
    NSString *msg = [[NSString alloc] initWithFormat:[NSString stringWithFormat:@"%@",format] arguments:ap];   
    va_end (ap);
    fprintf(stderr,"%s%50s:%3d - %s",[prefix UTF8String], funcName, lineNumber, [msg UTF8String]);
    [msg release];
}
@end

然后将项目广告导入您的<application>-Prefix.pch

#import "Log.h"

现在，每次对NSLog的调用都将替换为您的自定义函数，而无需触及现有代码。但是，上面的功能只是打印到控制台。要添加文件输出，请在_Log：

上添加此功能

void append(NSString *msg){
    // get path to Documents/somefile.txt
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"logfile.txt"];
    // create if needed
    if (![[NSFileManager defaultManager] fileExistsAtPath:path]){
        fprintf(stderr,"Creating file at %s",[path UTF8String]);
        [[NSData data] writeToFile:path atomically:YES];
    } 
    // append
    NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:path];
    [handle truncateFileAtOffset:[handle seekToEndOfFile]];
    [handle writeData:[msg dataUsingEncoding:NSUTF8StringEncoding]];
    [handle closeFile];
}

并在_Log函数中将此行添加到fprintf下面：

append(msg);

文件编写也适用于您的iPhone设备，但该文件将在其中的目录中创建，除非您添加代码将其发送回Mac或在其上显示，否则您将无法访问该文件。查看应用程序内部，或使用iTunes添加文档目录。

Answer 2

有一种更容易的方法。以下是将 NSLog 输出重定向到应用程序的Documents文件夹中的文件的方法。当您想要在开发工作室之外测试应用程序时，这非常有用，可以从Mac上拔下。

<强> ObjC：

- (void)redirectLogToDocuments 
{
     NSArray *allPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
     NSString *documentsDirectory = [allPaths objectAtIndex:0];
     NSString *pathForLog = [documentsDirectory stringByAppendingPathComponent:@"yourFile.txt"];

     freopen([pathForLog cStringUsingEncoding:NSASCIIStringEncoding],"a+",stderr);
}

<强>夫特：

func redirectLogToDocuments() {

    let allPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = allPaths.first!
    let pathForLog = documentsDirectory.stringByAppendingString("/yourFile.txt")

    freopen(pathForLog.cStringUsingEncoding(NSASCIIStringEncoding)!, "a+", stderr)
}

执行此方法后，NSLog（ObjC）或print（Swift）生成的所有输出都将转发到指定文件。要保存已保存的文件Organizer，请浏览应用程序的文件并将Application Data保存在文件系统中的某个位置，而不是只浏览到Documents文件夹。

Answer 3

将JaakL的答案翻译为 Swift ，无论如何其他人也需要将其发布在此处

在应用程序的某个地方运行此代码，从那时起它将所有NSLog（）输出存储到文件目录中的文件中。

let docDirectory: NSString = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0] as NSString
let logpath = docDirectory.stringByAppendingPathComponent("YourFileName.txt")
freopen(logpath.cStringUsingEncoding(NSASCIIStringEncoding)!, "a+", stderr)

额外：如何使用Xcode查找日志文件：
您只需从Xcode访问日志：Windows＆gt;装置＆gt;选择你的应用＆gt; InfoWheelButton＆gt;下载容器。使用finder查看文件：在文件上单击鼠标右键＆gt;显示包裹内容＆gt; appdata＆gt;文件＆gt;那里的文件是

Answer 4

我找到了解决问题的最简单方法：Logging to a file on the iPhone。无需更改任何NSLog代码或更改记录器本身，只需将这4行添加到didFinishLaunchingWithOptions，并确保在您的构建设置中，实时发布不会激活此功能（我为此添加了LOG2FILE标志）。

#ifdef LOG2FILE
 #if TARGET_IPHONE_SIMULATOR == 0
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *logPath = [documentsDirectory stringByAppendingPathComponent:@"console.log"];
    freopen([logPath cStringUsingEncoding:NSASCIIStringEncoding],"a+",stderr);
 #endif
#endif

Answer 5

确定！首先，我要感谢Evan-Mulawski。这是我的解决方案，也许对某人有帮助：

在AppDelegate中我添加了Function：

void logThis(NSString* Msg, ...)
{   
    NSArray* findingMachine = [Msg componentsSeparatedByString:@"%"];
    NSString* outputString = [NSString stringWithString:[findingMachine objectAtIndex:0]];
    va_list argptr;
    va_start(argptr, Msg);

    for(int i = 1; i < [findingMachine count]; i++) {
        if ([[findingMachine objectAtIndex:i] hasPrefix:@"i"]||[[findingMachine objectAtIndex:i] hasPrefix:@"d"]) {
            int argument = va_arg(argptr, int); /* next Arg */
            outputString = [outputString stringByAppendingFormat:@"%i", argument];      
            NSRange range;
            range.location = 0;
            range.length = 1;
            NSString* tmpStr = [[findingMachine objectAtIndex:i] stringByReplacingCharactersInRange:range withString:@""];
            outputString = [outputString stringByAppendingString:tmpStr];
        }
        else if ([[findingMachine objectAtIndex:i] hasPrefix:@"@"]) {
            id argument = va_arg(argptr, id);
            // add argument and next patr of message    
            outputString = [outputString stringByAppendingFormat:@"%@", argument];
            NSRange range;
            range.location = 0;
            range.length = 1;
            NSString* tmpStr = [[findingMachine objectAtIndex:i] stringByReplacingCharactersInRange:range withString:@""];
            outputString = [outputString stringByAppendingString:tmpStr];
        }
        else if ([[findingMachine objectAtIndex:i] hasPrefix:@"."]) {
            double argument = va_arg(argptr, double);       
            // add argument and next patr of message    
            outputString = [outputString stringByAppendingFormat:@"%f", argument];
            NSRange range;
            range.location = 0;
            range.length = 3;
            NSString* tmpStr = [[findingMachine objectAtIndex:i] stringByReplacingCharactersInRange:range withString:@""];
            outputString = [outputString stringByAppendingString:tmpStr];
        }
        else if ([[findingMachine objectAtIndex:i] hasPrefix:@"f"]) {
            double argument = va_arg(argptr, double);       
            // add argument and next patr of message    
            outputString = [outputString stringByAppendingFormat:@"%f", argument];
            NSRange range;
            range.location = 0;
            range.length = 1;
            NSString* tmpStr = [[findingMachine objectAtIndex:i] stringByReplacingCharactersInRange:range withString:@""];
            outputString = [outputString stringByAppendingString:tmpStr];
        }
        else {
            outputString = [outputString stringByAppendingString:@"%"];
            outputString = [outputString stringByAppendingString:[findingMachine objectAtIndex:i]];
        }
    }
    va_end(argptr);
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    NSString *  filePath = [[paths objectAtIndex:0]stringByAppendingPathComponent:@"logFile.txt"];
    NSError* theError = nil;
    NSString * fileString = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&theError];
    if (theError != nil||[fileString length]==0) {
        fileString = [NSString stringWithString:@""];
    }
    fileString = [fileString stringByAppendingFormat:@"\n%@",outputString];
    if(![fileString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&theError])
    {
            NSLog(@"Loging problem");
    }

    NSLog(@"%@",outputString);
}

然后使用“替换所有”NSLog - ＆gt; logThis。此代码适用于我的应用程序。它可以根据不同的需求进行扩展。

寻求帮助。

Answer 6

这是我使用和运作良好的方法：

http://parmanoir.com/Redirecting_NSLog_to_a_file

希望它有所帮助。

我只是为了内容而在这里发布

- (BOOL)redirectNSLog { 
     // Create log file 
     [@"" writeToFile:@"/NSLog.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil]; 
     id fileHandle = [NSFileHandle fileHandleForWritingAtPath:@"/NSLog.txt"]; 
     if (!fileHandle) return NSLog(@"Opening log failed"), NO; 
     [fileHandle retain];  

     // Redirect stderr 
     int err = dup2([fileHandle fileDescriptor], STDERR_FILENO); 
     if (!err) return NSLog(@"Couldn't redirect stderr"), NO;  return YES; 
}

Answer 7

Swift 2.0：

将这些添加到Appdelegate didFinishLaunchWithOptions。

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    var paths: Array = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory: String = paths[0]
    let logPath: String = documentsDirectory.stringByAppendingString("/console.log")

    if (isatty(STDERR_FILENO) == 0)
    {
        freopen(logPath, "a+", stderr)
        freopen(logPath, "a+", stdin)
        freopen(logPath, "a+", stdout)
    }
    print(logPath)

    return true
}

访问console.log：

在Xcode Log Area上打印日志路径时，选择路径，右键单击，在Finder中选择Services- Reaveal并打开文件console.log

Answer 8

Swift 4版本

let docDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let logpathe = docDirectory.appendingPathComponent("Logerr.txt")
freopen(logpathe.path.cString(using: .ascii)!, "a+", stderr)
let logpatho = docDirectory.appendingPathComponent("Logout.txt")
freopen(logpatho.path.cString(using: .ascii)!, "a+", stdout)

Swift print()的输出将位于stdout

Answer 9

我对阿尔文乔治的答案做了一点工作。

为了控制日志文件的大小，我实现了（快速和脏）一个＆＃34; 10代日志文件＆＃34;解决方案并添加一个func以便稍后删除它们

每次应用启动时，它都会生成一个带有索引＆＃34; 0＆＃34;的新日志文件。将使用比以前更高的索引重命名现有文件。索引＆＃34; 10＆＃34;将被删除。

因此，每次启动都会为您提供一个新的日志文件，最多10代

可能不是最优雅的方式，但在过去的几周里我的工作非常好，因为我需要一些长时间的记录＆＃34;关闭mac＆＃34;

  // -----------------------------------------------------------------------------------------------------------
  // redirectConsoleToFile()
  //
  // does two things  
  // 1) redirects "stderr", "stdin" and "stdout" to a logfile
  // 2) deals with old/existing files to keep up to 10 generations of the logfiles
  // tested with IOS 9.4 and Swift 2.2
  func redirectConsoleToFile() {

    // Instance of a private filemanager
    let myFileManger = NSFileManager.defaultManager()

    // the path of the documnts directory of the app
    let documentDirectory: String = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first!

    // maximum number of logfiles
    let maxNumberOfLogFiles: Int = 10

    // look if the max number of files already exist
    var logFilePath : String = documentDirectory.stringByAppendingString("/Console\(maxNumberOfLogFiles).log")
    var FlagOldFileNoProblem: Bool = true
    if myFileManger.fileExistsAtPath(logFilePath) == true {

        // yes, max number of files reached, so delete the oldest one
        do {
            try myFileManger.removeItemAtPath(logFilePath)

        } catch let error as NSError {

            // something went wrong
            print("ERROR deleting old logFile \(maxNumberOfLogFiles): \(error.description)")
            FlagOldFileNoProblem = false
        }
    }

    // test, if there was a problem with the old file
    if FlagOldFileNoProblem == true {

        // loop over all possible filenames
        for i in 0 ..< maxNumberOfLogFiles {

            // look, if an old file exists, if so, rename it with an index higher than before
            logFilePath = documentDirectory.stringByAppendingString("/Console\((maxNumberOfLogFiles - 1) - i).log")
            if myFileManger.fileExistsAtPath(logFilePath) == true {

                // there is an old file
                let logFilePathNew = documentDirectory.stringByAppendingString("/WayAndSeeConsole\(maxNumberOfLogFiles - i).log")
                do {

                    // rename it
                    try myFileManger.moveItemAtPath(logFilePath, toPath: logFilePathNew)

                } catch let error as NSError {

                    // something went wrong
                    print("ERROR renaming logFile: (i = \(i)), \(error.description)")
                    FlagOldFileNoProblem = false
                }
            }
        }
    }

    // test, if there was a problem with the old files
    if FlagOldFileNoProblem == true {

        // No problem so far, so try to delete the old file
        logFilePath = documentDirectory.stringByAppendingString("/Console0.log")
        if myFileManger.fileExistsAtPath(logFilePath) == true {

            // yes, it exists, so delete it
            do {
                try myFileManger.removeItemAtPath(logFilePath)

            } catch let error as NSError {

                // something went wrong
                print("ERROR deleting old logFile 0: \(error.description)")
            }
        }
    }

    // even if there was a problem with the files so far, we redirect
    logFilePath = documentDirectory.stringByAppendingString("/Console0.log")

    if (isatty(STDIN_FILENO) == 0) {
        freopen(logFilePath, "a+", stderr)
        freopen(logFilePath, "a+", stdin)
        freopen(logFilePath, "a+", stdout)
        displayDebugString(DEBUG_Others, StringToAdd: "stderr, stdin, stdout redirected to \"\(logFilePath)\"")
    } else {
        displayDebugString(DEBUG_Others, StringToAdd: "stderr, stdin, stdout NOT redirected, STDIN_FILENO = \(STDIN_FILENO)")
    }
}

// -----------------------------------------------------------------------------------------------------------
// cleanupOldConsoleFiles()
//
// delete all old consolfiles
func cleanupOldConsoleFiles() {

    // Instance of a private filemanager
    let myFileManger = NSFileManager.defaultManager()

    // the path of the documnts directory of the app
    let documentDirectory: String = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first!

    // maximum number of logfiles
    let maxNumberOfLogFiles: Int = 10

    // working string
    var logFilePath: String = ""

    // loop over all possible filenames
    for i in 0 ... maxNumberOfLogFiles {

        // look, if an old file exists, if so, rename it with an index higher than before
        logFilePath = documentDirectory.stringByAppendingString("/Console\(i).log")
        if myFileManger.fileExistsAtPath(logFilePath) == true {

            // Yes, file exist, so delete it
            do {
                try myFileManger.removeItemAtPath(logFilePath)
            } catch let error as NSError {

                // something went wrong
                print("ERROR deleting old logFile \"\(i)\": \(error.description)")
            }
        }
    }
}

如何将NSLog转换为文件

9 个答案:

选项1：使用ASL

选项2：写入文件