五个按钮保持等距的圆形旋转

Question

我想在半径为 100 的圆的圆周上旋转五个按钮（圆心为 (120,120)，实际上是正方形视图的中心，即 240*240）。是否可以这样做，通过交互带有旋转的按钮和正确的外观。

我试过了'

x =  round(cx + redious * cos(angl));
y =  round(cy - redious * sin(angl));   

NSString *X=[NSString stringWithFormat:@"%f",x];
[xval addObject:[NSString stringWithFormat:@"%@",X]];
NSString *Y=[NSString stringWithFormat:@"%f",y];
[yval addObject:[NSString stringWithFormat:@"%@",Y]];'

计算点数和：

map.frame= CGRectMake([[fqx objectAtIndex:counter1]intValue],[[fqy objectAtIndex:counter1]intValue], 72, 37);   
website.frame= CGRectMake([[fqx objectAtIndex:counter2]intValue],[[fqy objectAtIndex:counter2]intValue], 72, 37);   
share.frame= CGRectMake([[fqx objectAtIndex:counter3]intValue],[[fqy objectAtIndex:counter3]intValue], 72, 37); 
slideShow.frame= CGRectMake([[fqx objectAtIndex:counter4]intValue],[[fqy objectAtIndex:counter4]intValue], 72, 37);' 

旋转但它会产生奇怪的路径..以三角形方式.. ('map','share','slideShow','website') 是我的按钮.. :P

Answer 1

这太可爱了，不能错过，所以就在这里。此代码仅限于一个按钮旋转，但我怀疑您将无法将其扩展为多个（提示：使用一个 CADisplayLink 并在其中一次旋转所有按钮）。

- (void)setupRotatingButtons
{
    // call this method once; make sure "self.view" is not nil or the button 
    // won't appear. the below variables are needed in the @interface.
    // center: the center of rotation
    // radius: the radius
    // time:   a CGFloat that determines where in the cycle the button is located at
    //         (note: it will keep increasing indefinitely; you need to use 
    //         modulus to find a meaningful value for the current position, if
    //         needed)
    // speed:  the speed of the rotation, where 2 * M_PI is 1 lap a second
    // b:      the UIButton
    center = CGPointMake(100, 100);
    radius = 100;
    time = 0;
    speed = 2 * M_PI; // <-- will rotate CW 360 degrees per second (1 "lap"/s)

    b = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];
    b.titleLabel.text = @"Hi";
    b.frame = CGRectMake(0.f, 0.f, 100, 50);
    // we get the center set right before we add subview, to avoid glitch at start
    [self continueCircling:nil]; 
    [self.view addSubview:b];
    [self.view bringSubviewToFront:b];
    CADisplayLink *dl = [CADisplayLink displayLinkWithTarget:self 
        selector:@selector(continueCircling:)];
    [dl addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
}

我们还需要实际的“continueCircling:”方法，很简单：

- (void)continueCircling:(CADisplayLink *)dl
{
    time += speed * dl.duration;
    b.center = CGPointMake(center.x + radius * cosf(time), 
                           center.y + radius * sinf(time));
}

我敢肯定还有其他更漂亮的方法可以解决这个问题，但上述方法至少有效。 :)

编辑：我忘了提，你需要添加 QuartzCore 框架和

#import <QuartzCore/QuartzCore.h> 

对于 CADisplayLink。

编辑 2：找到 PI 常数 (M_PI)，因此将 3.1415 替换为该常数。