使用 NSTimer 创建倒计时

发布于 2024-10-19 03:41:12 字数 375 浏览 1 评论 0原文

我有一个 int 值，表示事件的倒计时（正在显示的视图）。目前，我这样做：

- (void) buttonTapped:(id)sender {
    [self performSelector:@selector(displayView) afterDelay:countdownValue];
}

我想做的是以下...

当点击按钮时，将导航栏的色调颜色按比例更改为红色，黄色，绿色，直到倒计时到期，然后显示视图。

例如，如果我的倒计时是 3 秒，则每种颜色一秒，如果是 5 秒，则每种颜色 1.666。

我可以使用 NSTimer 来安排这个吗？

显示视图后，计时器需要失效。

谢谢

原文

I have a int value representing a countdown to an event (view being displayed). Currently, i do this:

- (void) buttonTapped:(id)sender {
    [self performSelector:@selector(displayView) afterDelay:countdownValue];
}

What I would like to do is the following...

When the button is tapped, change the tint colour of my navigation bar to red, yellow, green proportionally, until the countdown expires, then display the view.

So for example if my countdown is 3 seconds, one second for each colour, if it is 5 seconds, 1.666 for each colour.

Can I use an NSTimer to schedule this?

After the view is displayed the timer would need invalidating.

Thanks

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半边脸i 2024-10-26 03:41:12

float count_down = 5.0;
[NSTimer scheduledTimerWithTimeInterval: count_down*(1.0/3.0) target: self
                               selector: @selector(changeToRed:) userInfo: nil repeats: NO];
[NSTimer scheduledTimerWithTimeInterval: count_down*(2.0/3.0) target: self
                               selector: @selector(changeToGreen:) userInfo: nil repeats: NO];
[NSTimer scheduledTimerWithTimeInterval: count_down target: self
                               selector: @selector(changeToBlue:) userInfo: nil repeats: NO];

和回调（在那里做任何你想做的事情）：

-(void) changeToRed:(NSTimer*) t {
    NSLog(@"red");
}

-(void) changeToGreen:(NSTimer*) t {
    NSLog(@"green");
}

-(void) changeToBlue:(NSTimer*) t {
    NSLog(@"blue");
}

float count_down = 5.0;
[NSTimer scheduledTimerWithTimeInterval: count_down*(1.0/3.0) target: self
                               selector: @selector(changeToRed:) userInfo: nil repeats: NO];
[NSTimer scheduledTimerWithTimeInterval: count_down*(2.0/3.0) target: self
                               selector: @selector(changeToGreen:) userInfo: nil repeats: NO];
[NSTimer scheduledTimerWithTimeInterval: count_down target: self
                               selector: @selector(changeToBlue:) userInfo: nil repeats: NO];

And callbacks (do whatever you want there):

-(void) changeToRed:(NSTimer*) t {
    NSLog(@"red");
}

-(void) changeToGreen:(NSTimer*) t {
    NSLog(@"green");
}

-(void) changeToBlue:(NSTimer*) t {
    NSLog(@"blue");
}

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