调用睡眠(5)；和更新文本字段不起作用 [英] Calling sleep(5); and updating text field not working

问题描述

我正在尝试使方法休眠(见下文)，而不是 textLabel 从 myTextLabelString 的值更改，等待 5 秒，更改为sleep5 工作"，等待 5 秒，最后更改为睡眠 5 工作第二次"......它只是从 myTextLabelString 的值开始，等待 10 秒，然后更改为睡眠 5"第二次工作".

I'm trying to sleep a method (see below), but rather than the textLabel changing from the value of myTextLabelString, waiting 5 seconds, changing to "sleep 5 worked", waiting 5 seconds and finally changing to "sleep 5 worked second time round".... it just goes from the value of myTextLabelString, waits 10 seconds, and then changes to "sleep 5 worked second time round".

- (void)textLabelChanger:(id)sender {

    NSString *myTextLabelString = [NSString stringWithFormat:@"%d", gameCountDown];    

    textLabel.text=myTextLabelString;
    sleep(5);
    textLabel.text=@"sleep 5 worked";
    sleep(5);
    textLabel.text=@"sleep 5 worked second time round";
    return;
}

推荐答案

这可能会提供您寻求的结果:

This will probably provide the result that you seek:

-(void)textLabelChanger:(id)sender
{
    NSString *myTextLabelString = [NSString stringWithFormat:@"%d", gameCountDown];    
    textLabel.text=myTextLabelString;

    [self performSelector:@selector(updateTextLabelWithString:) withObject:@"sleep 5 worked" afterDelay:5.0];
    [self performSelector:@selector(updateTextLabelWithString:) withObject:@"sleep 5 worked second time round" afterDelay:10.0];
}

-(void)updateTextLabelWithString:(NSString*)theString
{
    textLabel.text=theString;
}

有很多方法可以做到这一点.您可以使用 doFirstTextUpdate 编写sleep 5 working"，然后调用另一个选择器，例如 ，而不是使用一个 updateTextLabelWithString 以不同的延迟调用两次doSecondTextUpdate 使用相同的 [self performSelector:] 技术，再延迟 5 秒.

There are plenty of ways to do this. Instead of having a single updateTextLabelWithString that you call twice with different delays, you could have a doFirstTextUpdate that writes the "sleep 5 worked" and then calls another selector like doSecondTextUpdate using the same [self performSelector:] technique after another 5 second delay.

在 Objective-C 中使用 sleep() 方法的情况极为罕见.

It's exceedingly rare that you'll need to use the sleep() method with Objective-C.

-(void)textLabelChanger:(id)sender
{
    NSString *myTextLabelString = [NSString stringWithFormat:@"%d", gameCountDown];    
    textLabel.text=myTextLabelString;

    [self performSelector:@selector(firstUpdate) withObject:nil afterDelay:5.0];
}
-(void)firstUpdate
{
    textLabel.text = @"sleep 5 worked";
    [self performSelector:@selector(secondUpdate) withObject:nil afterDelay:5.0];
}
-(void)secondUpdate
{
    textLabel.text = @"sleep 5 worked second time round";
}

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