Objective-C，定期在后台运行NSTask

Question

Objective-C，定期在后台运行NSTask

3

我看到了一些关于如何在后台保持NSTask运行的好信息，尽管那不完全是我想做的。我想做的是定期在后台运行NSTask（例如每30秒），然后结束它；这可能是我想要做的一个示例：

NSTask *theTask = [ [ NSTask alloc ] init ];
NSPipe *taskPipe = [ [ NSPipe alloc ] init ];

[ theTask setStandardError:taskPipe ];
[ theTask setStandardOutput:taskPipe ];
[ theTask setLaunchPath:@"/bin/ls" ];
[ theTask setArguments:[ NSArray arrayWithObject:@"-l" ] ];
[ theTask launch ];

// Wait 30 seconds, then repeat the task

- Joe Habadas

1个回答

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- aleroot · Accepted Answer

也许您可以简单地使线程进入休眠状态，并在 do 循环中等待 30 秒钟：

do {

[ theTask launch ]; //Launch the Task
sleep(30);          //Sleep/wait 30 seconds 

} while (someCondition);

否则，您可以使用 NSTimer：

NSTimer *t = [NSTimer scheduledTimerWithTimeInterval: 30.0
                      target: self
                      selector:@selector(onTick:)
                      userInfo: nil repeats:YES];


- (void)onTick:(NSTimer *)timer {
    //In this method that will be get called each 30 seconds, 
    //you have to put the action that you want to perform ...
    [ theTask launch ];
}