小编Bik*_*ram的帖子

我正在尝试获取单个应用程序的总体CPU使用率。我找到了一些资源，但是它们要么是用C编写的，要么是过时的。谁能帮助我解决这个问题？我正在尝试将此 https://github.com/beltex/SystemKit/blob/master/SystemKit/System.swift#L12转换 为快速。

到现在为止我已经可以转换这么多

fileprivate func hostCPULoadInfo() -> host_cpu_load_info{

        let  HOST_CPU_LOAD_INFO_COUNT = MemoryLayout<host_cpu_load_info>.stride / MemoryLayout<integer_t>.stride;

        var size = mach_msg_type_number_t(HOST_CPU_LOAD_INFO_COUNT);
        var hostInfo = host_cpu_load_info_t.allocate(capacity: 1);

        let result = withUnsafeMutablePointer(to: &hostInfo) {$0.withMemoryRebound(to: integer_t.self, capacity: Int(size)){
            host_info(mach_host_self(), Int32(HOST_BASIC_INFO), $0, &size)
            }
        }

        let data = hostInfo.move()
        hostInfo.deallocate(capacity: 1)


        #if DEBUG
            if result != KERN_SUCCESS{
                print("Error  - \(#file): \(#function) - kern_result_t = \(result)");
            }
        #endif

        return data;
    }

public func cpuUsage() -> (system: Double, user: Double, idle : Double, nice: Double){
        let load = …

我正在尝试在视图控制器中制作一个动画，其中圆随着动画旋转。圆应该旋转直到完成以下gif所示的过程。我已经实现了圆形动画，但无法达到想要实现的目标。

import UIKit

class ViewController: UIViewController {

    var circle : Circle?;

    override func viewDidLoad() {
        super.viewDidLoad();

        view.backgroundColor = UIColor.white;

        setupViews();
    }

    func setupViews(){
        circle = Circle(frame: self.view.frame);

        view.addSubview(circle!);

        circle?.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true;
        circle?.topAnchor.constraint(equalTo: view.topAnchor).isActive = true;
        circle?.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true;
        circle?.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true;

    }

}

class Circle : UIView{


    override init(frame: CGRect) {
        super.init(frame: frame);

        self.backgroundColor = .blue;
        self.translatesAutoresizingMaskIntoConstraints = false;

        setupCircle();
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    let gradientLayer = CAGradientLayer();


    func …