NSTask waitUntilExit挂载应用程序在越狱iOS [英] NSTask waitUntilExit hanging app on jailbroken iOS

问题描述

所以我有NSTask运行一个脚本，它生成一个东西，一个txt，我从中读取的列表。但是如果我使用我当前的代码（下面），警报在NSTask完成之前弹出，从而导致空白警报。我尝试了 waitUntilExit ，但是这使得调用此操作的按钮冻结，但UI不锁定自己。

So I've got NSTask to run a script which generates a list of something, into a txt, which I read from. But if I use my current code (below), the alert pops up before the NSTask is finished, thus resulting in a blank alert. I've tried waitUntilExit but that makes the button that invokes this action freeze, but the UI doesn't lock up itself.

- (void) runSupported {
    stask = [[NSTask alloc] init];
    [stask setLaunchPath:@"/bin/bash"];
    NSString *script;
    script = [[[NSBundle mainBundle] bundlePath] stringByAppendingString:@"/apps.sh"];
    NSArray *sargs = [NSArray arrayWithObjects:script, @"-txt", nil];
    [stask setArguments: sargs];
    [stask launch];

    NSString *apps;
    apps = [NSString stringWithContentsOfFile:@"/var/mobile/supported.txt" encoding:NSUTF8StringEncoding error:nil];
    NSFileManager *fm = [NSFileManager defaultManager];
    if ([fm fileExistsAtPath:apps]) {
        UIAlertView *supported = [[UIAlertView alloc] initWithTitle:@"App List" message:apps delegate:self cancelButtonTitle:@"Ok!" otherButtonTitles:nil];
        [supported show];
        [supported release];
    } else {
        UIAlertView *supported = [[UIAlertView alloc] initWithTitle:@"App List" message:@"Error generating list." delegate:self cancelButtonTitle:@"Ok!" otherButtonTitles:nil];
        [supported show];
        [supported release];
    }
}

任何想法我如何完成NSTask调用警报？感谢。

Any idea how I'd have the NSTask finish before invoking the alert? Thanks.

编辑：使用NSNotification的代码：

Code with NSNotification:

-(IBAction) supported {
    stask = [[NSTask alloc] init];
    [stask setLaunchPath:@"/bin/bash"];
    NSString *script;
    script = [[[NSBundle mainBundle] bundlePath] stringByAppendingString:@"/apps.sh"];
    NSArray *sargs = [NSArray arrayWithObjects:script, @"-txt", nil];
    [stask setArguments: sargs];
    [[NSNotificationCenter defaultCenter] addObserver: self
                                             selector: @selector(taskEnded:)
                                                 name: NSTaskDidTerminateNotification
                                               object: nil]; 
    [stask launch];
}

- (void)taskEnded:(NSNotification *)notification {
    if (stask == [[notification object] terminationStatus]) {
        NSString *apps;
        apps = [NSString stringWithContentsOfFile:@"/var/mobile/supported.txt" encoding:NSUTF8StringEncoding error:nil];
        NSFileManager *fm = [NSFileManager defaultManager];
        if ([fm fileExistsAtPath:apps]) {
            UIAlertView *supported = [[UIAlertView alloc] initWithTitle:@"Apps" message:apps delegate:self cancelButtonTitle:@"Ok!" otherButtonTitles:nil];
            [supported show];
            [supported release];
        } else {
            UIAlertView *supported = [[UIAlertView alloc] initWithTitle:@"Apps" message:@"Error generating list." delegate:self cancelButtonTitle:@"Ok!" otherButtonTitles:nil];
            [supported show];
            [supported release];
        }
    } else {
        NSLog(@"Task failed."); 
    }
}

推荐答案

Don 't use waitUntilExit 。

Don't use waitUntilExit.

问题是如何在任务完成后不阻塞UI冻结那一个按钮）。对于所有类似问题，解决方案是在任务完成时通知，并且响应该通知继续进行（显示警报）。

The problem is how to do something after the task finishes without blocking the UI (or freezing that one button). The solution, as for all similar problems, is to be notified when the task finishes, and proceed further (show the alert) in response to that notification.

在这种情况下，通知是一个名为 NSTaskDidTerminateNotification 的NSNotification。当任务退出时，由于任何原因，NSTask对象将在默认NSNotificationCenter上发布此通知。您可以询问任务的终止状态，以确定其成功，失败或崩溃。

The notification, in this case, is an NSNotification named NSTaskDidTerminateNotification. When the task exits, for any reason, the NSTask object will post this notification on the default NSNotificationCenter. You can ask the task what its termination status was to determine whether it succeeded, failed, or crashed.

另请参阅：通知编程主题。

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