NSFileHandle readInBackgroundAndNotify不起作用 [英] NSFileHandle readInBackgroundAndNotify does not work

问题描述

我正在使用NSFileHandle的readInBackgroundAndNotify方法在更新日志文件时获取通知.

Hi I'm using NSFileHandle's readInBackgroundAndNotify method to get notifications when a log file has been updated.

我有以下代码:

- (void)startReading
{
    NSString *logPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Logs/MyTestApp.log"];
    NSFileHandle *fh = [NSFileHandle fileHandleForReadingAtPath:logPath];
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    [notificationCenter addObserver:self
                           selector:@selector(getData:)
                               name:NSFileHandleReadCompletionNotification
                             object:fh];
    [fh readInBackgroundAndNotify];
}

- (void) getData: (NSNotification *)aNotification
{
     NSLog(@"notification received");
}

但是永远不会调用选择器，也不会收到通知.

However the selector is never called and the notification is not received.

推荐答案

1. 将NSLog添加到startReading以确保被调用.
2. 登录fh.我的猜测是它是nil(很可能是因为您尚未创建MyTestApp.log).

1. Add an NSLog to startReading to make sure that's getting called.
2. Log fh. My guess is that it's nil (most probably because you haven't created MyTestApp.log yet).

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