调用sleep（5）;并更新文本字段不工作

问题描述

我尝试睡眠一个方法（见下文），而不是 textLabel 从的值更改myTextLabelString ，等待5秒，更改为睡眠5工作，等待5秒，最后更改为睡眠5工作第二次回合....它只是从的值myTextLabelString ，等待10秒，然后更改为sleep 5 working second time round。

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

您寻求：

-(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。而不是有一个 updateTextLabelWithString 你调用两次不同的延迟，你可以有一个 doFirstTextUpdate 写入sleep 5工作，然后再调用另一个选择器如 doSecondTextUpdate 使用相同的 [self performSelector：] 。

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.

这是非常罕见的，你需要使用Objective-C sleep（） / p>

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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