ios学习随笔四

import UIKit
class progresscustom: UIView {
    override init(frame: CGRect) {
    super.init(frame: frame)
        self.backgroundColor = UIColor(white: 1, alpha: 0)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private var _progressValue :CGFloat = 0
      
    internal func getProgressVlue() ->CGFloat{
        return _progressValue ;
    }
  internal func setProgressValue(value : CGFloat){
        _progressValue = value ;
        setNeedsDisplay() ;
    }
    
    // Only override drawRect: if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.当子图需要表现在VIew上的时候，需要重写这个方法
    override func drawRect(rect: CGRect) {
        // Drawing code
        var ctx = UIGraphicsGetCurrentContext() ;
        var r = rect.width/2       
        CGContextAddArc(ctx,r, r, r, 0, 3.1415926*2, 0)
        CGContextAddLineToPoint(ctx, r, r)
        CGContextSetRGBFillColor(ctx, 0.7, 0.7, 0.7, 1)
        CGContextFillPath(ctx)
        CGContextAddArc(ctx,r, r, r, 0, 3.1415926*2*_progressValue, 0)
        CGContextAddLineToPoint(ctx, r, r)
        CGContextSetRGBFillColor(ctx, 0, 0, 1, 1)
        CGContextFillPath(ctx)
        CGContextStrokePath(ctx)
        CGContextSetLineWidth(ctx, 5)
    }