ios - Objective-C CGAffineTransformRotate 不起作用

Question

嘿，需要你的帮助，

我正在尝试为我的 iPhone 创建一个模拟时钟。问题是，UIImage 没有以正确的方式移动或没有移动，大多数时候它在整个 View 中旋转。是否缺少任何框架，我将度数转换为弧度...这是代码:

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    // Getting a Timer
    NSTimer *timer = [[NSTimer alloc]init];
    timer = [NSTimer scheduledTimerWithTimeInterval: 1 target:self
                                           selector:@selector(tick:) userInfo:nil repeats:YES];
    [timer fire];
    self.ticker = 0;
    self.minutes = 0;
    self.hours = 0;
}

- (void)tick:(NSTimer *)theTimer
{
    //Turning Seconds into Minutes and Hours
    self.ticker ++;
    self.timerLabel.text = [NSString stringWithFormat:@"%d",self.ticker];
    self.seconds = self.ticker;
    if (self.seconds == 60){
        self.ticker = 0;
        self.seconds = 0;
        self.minutes ++;
    }
    if (self.minutes == 60){
        self.minutes = 0;
        self.hours ++;
    }

    //Main issue here...
    // 360° / 60 second = 6° per second
    double grad = self.ticker * 6;
    //Converting Grad into Rad
    double rad = M_PI * grad / 180;
    //Set Transformation ---> CGAffineTransformMakeRotation does not work eighter
    CGAffineTransform transform = CGAffineTransformRotate(self.pointerImage.transform, rad);
    //Set Transformation to UIImageView caleld pointerImage
    self.pointerImage.transform = transform;
    //self.pointerImage.center = CGPointMake(160, 420);
    //NSLog(@"%f", grad);



    if ( self.ticker == 60){
        self.ticker = 0;
    }

}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Answer 1

围绕圆心的旋转需要初始变换来偏移边界 - 因此变换位于圆心。您肯定会在此站点上找到示例代码。我强烈建议您创建一个单 View 项目，向其中添加一个彩色方形 View ，然后尝试使其正确旋转。然后才采用该代码并将其集成到您的实际项目中。