圆形进度条在IOS(Circular Progress Bars in IOS)

我想创建像下面这样的圆形进度条：

我怎样才能做到这一点使用Objective-C和Cocoa？

我该如何开始做它创建一个UIView和编辑的drawRect，但我有点失落。 任何帮助将不胜感激。

谢谢！

Answer 1:

基本概念是使用UIBezierPath类，你的优势。 你能画出弧线，它实现你后的效果。 我只有一个半小时左右有此一条缝，但我尝试如下。

非常简陋，它只是使用路径上的行程，但在这里我们去。 你可以改变/修改这对您的具体需求，而是做圆弧倒计时的逻辑将是非常相似的。

在视图类：

@interface TestView () {
    CGFloat startAngle;
    CGFloat endAngle;
}

@end

@implementation TestView

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        self.backgroundColor = [UIColor whiteColor];

        // Determine our start and stop angles for the arc (in radians)
        startAngle = M_PI * 1.5;
        endAngle = startAngle + (M_PI * 2);

    }
    return self;
}

- (void)drawRect:(CGRect)rect
{
    // Display our percentage as a string
    NSString* textContent = [NSString stringWithFormat:@"%d", self.percent];

    UIBezierPath* bezierPath = [UIBezierPath bezierPath];

    // Create our arc, with the correct angles
    [bezierPath addArcWithCenter:CGPointMake(rect.size.width / 2, rect.size.height / 2) 
                          radius:130 
                      startAngle:startAngle
                        endAngle:(endAngle - startAngle) * (_percent / 100.0) + startAngle
                       clockwise:YES];

    // Set the display for the path, and stroke it
    bezierPath.lineWidth = 20;
    [[UIColor redColor] setStroke];
    [bezierPath stroke];

    // Text Drawing
    CGRect textRect = CGRectMake((rect.size.width / 2.0) - 71/2.0, (rect.size.height / 2.0) - 45/2.0, 71, 45);
    [[UIColor blackColor] setFill];
    [textContent drawInRect: textRect withFont: [UIFont fontWithName: @"Helvetica-Bold" size: 42.5] lineBreakMode: NSLineBreakByWordWrapping alignment: NSTextAlignmentCenter];
}

对于视图控制器：

@interface ViewController () {    
    TestView* m_testView;
    NSTimer* m_timer;
}

@end

- (void)viewDidLoad
{
    // Init our view
    [super viewDidLoad];
    m_testView = [[TestView alloc] initWithFrame:self.view.bounds];
    m_testView.percent = 100;
    [self.view addSubview:m_testView];
}

- (void)viewDidAppear:(BOOL)animated
{
    // Kick off a timer to count it down
    m_timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(decrementSpin) userInfo:nil repeats:YES];
}

- (void)decrementSpin
{
    // If we can decrement our percentage, do so, and redraw the view
    if (m_testView.percent > 0) {
        m_testView.percent = m_testView.percent - 1;
        [m_testView setNeedsDisplay];
    }
    else {
       [m_timer invalidate];
       m_timer = nil;
    }
}

Answer 2:

我与幻数（为了更好的理解），例如：

  CAShapeLayer *circle = [CAShapeLayer layer];
  circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(29, 29) radius:27 startAngle:-M_PI_2 endAngle:2 * M_PI - M_PI_2 clockwise:YES].CGPath;
  circle.fillColor = [UIColor clearColor].CGColor;
  circle.strokeColor = [UIColor greenColor].CGColor;
  circle.lineWidth = 4;

  CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
  animation.duration = 10;
  animation.removedOnCompletion = NO;
  animation.fromValue = @(0);
  animation.toValue = @(1);
  animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
  [circle addAnimation:animation forKey:@"drawCircleAnimation"];

  [imageCircle.layer.sublayers makeObjectsPerformSelector:@selector(removeFromSuperlayer)];
  [imageCircle.layer addSublayer:circle];

Answer 3:

我实现了一个简单的库为iOS这样做。 它是基于UILabel类这样就可以显示你希望你的进度条里面什么的，但你也可以将其留空。

初始化完成后，你只需要一行代码来设置进度：

[_myProgressLabel setProgress:(50/100))];

图书馆被命名为KAProgressLabel

Answer 4:

您可以检查出我的lib MBCircularProgressBar

Answer 5:

对于斯威夫特利用这一点，

let circle = UIView(frame: CGRectMake(0,0, 100, 100))

circle.layoutIfNeeded()

let centerPoint = CGPoint (x: circle.bounds.width / 2, y: circle.bounds.width / 2)
let circleRadius : CGFloat = circle.bounds.width / 2 * 0.83

var circlePath = UIBezierPath(arcCenter: centerPoint, radius: circleRadius, startAngle: CGFloat(-0.5 * M_PI), endAngle: CGFloat(1.5 * M_PI), clockwise: true    )

let progressCircle = CAShapeLayer()
progressCircle.path = circlePath.CGPath
progressCircle.strokeColor = UIColor.greenColor().CGColor
progressCircle.fillColor = UIColor.clearColor().CGColor
progressCircle.lineWidth = 1.5
progressCircle.strokeStart = 0
progressCircle.strokeEnd = 0.22

circle.layer.addSublayer(progressCircle)

self.view.addSubview(circle)

参考：请参见这里 。

Answer 6:

斯威夫特3利用这一点，

CAShapeLayer与动画：继续扎伊德帕坦答。

    let circle = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))

    circle.layoutIfNeeded()

    var progressCircle = CAShapeLayer()

    let centerPoint = CGPoint (x: circle.bounds.width / 2, y: circle.bounds.width / 2)
    let circleRadius : CGFloat = circle.bounds.width / 2 * 0.83

    let circlePath = UIBezierPath(arcCenter: centerPoint, radius: circleRadius, startAngle: CGFloat(-0.5 * M_PI), endAngle: CGFloat(1.5 * M_PI), clockwise: true    )

    progressCircle = CAShapeLayer ()
    progressCircle.path = circlePath.cgPath
    progressCircle.strokeColor = UIColor.green.cgColor
    progressCircle.fillColor = UIColor.clear.cgColor
    progressCircle.lineWidth = 2.5
    progressCircle.strokeStart = 0
    progressCircle.strokeEnd = 1.0
     circle.layer.addSublayer(progressCircle)


    let animation = CABasicAnimation(keyPath: "strokeEnd")
    animation.fromValue = 0
    animation.toValue = 1.0
    animation.duration = 5.0
    animation.fillMode = kCAFillModeForwards
    animation.isRemovedOnCompletion = false
     progressCircle.add(animation, forKey: "ani")

    self.view.addSubview(circle)

文章来源: Circular Progress Bars in IOS