objective-c - IOS 中的圆形进度条

Question

我想创建一个圆形进度条，如下所示：

我如何使用 Objective-C 和 Cocoa 来做到这一点？

我是如何开始创建 UIView 并编辑 drawRect 的，但我有点迷失了。任何帮助将不胜感激。

谢谢！

Answer 1

基本概念是利用UIBezierPath课程来发挥自己的优势。您可以绘制弧线，从而达到您所追求的效果。我只有半个小时左右的时间来解决这个问题，但我的尝试在下面。

非常简陋，它只是在路径上使用笔画，但我们开始了。您可以根据您的确切需要更改/修改它，但是执行弧倒计时的逻辑将非常相似。

在视图类中：

@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

我的魔术数字示例（为了更好地理解）：

  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

我已经为 iOS 实现了一个简单的库。它基于 UILabel 类，因此您可以在进度条中显示您想要的任何内容，但您也可以将其留空。

初始化后，您只有一行代码来设置进度：

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

该库被命名为KAProgressLabel

Answer 4

你可以查看我的 lib MBCircularProgressBar

Answer 5

对于Swift使用这个，

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：见这里。

Answer 6

Swift 3 使用这个，

CAShapeLayer with Animation : 继续 Zaid Pathan ans。

    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)

Answer 7

这是一个Swift示例，说明如何制作一个简单的、不封闭的（为长数字留出空间）带有圆角和动画的圆形进度条。

open_circular_progress_bar.jpg

func drawBackRingFittingInsideView(lineWidth: CGFloat, lineColor: UIColor) {

    let halfSize:CGFloat = min( bounds.size.width/2, bounds.size.height/2)

    let desiredLineWidth:CGFloat = lineWidth

    let circle = CGFloat(Double.pi * 2)

    let startAngle = CGFloat(circle * 0.1)

    let endAngle = circle – startAngle

    let circlePath = UIBezierPath(

        arcCenter: CGPoint(x:halfSize, y:halfSize),

        radius: CGFloat( halfSize – (desiredLineWidth/2) ),

        startAngle: startAngle,

        endAngle: endAngle,

        clockwise: true)

    let shapeBackLayer = CAShapeLayer()

        shapeBackLayer.path = circlePath.cgPath

        shapeBackLayer.fillColor = UIColor.clear.cgColor

        shapeBackLayer.strokeColor = lineColor.cgColor

        shapeBackLayer.lineWidth = desiredLineWidth

        shapeBackLayer.lineCap = .round

    layer.addSublayer(shapeBackLayer)

}

以及动画功能。

 func animateCircle(duration: TimeInterval) {

    let animation = CABasicAnimation(keyPath: “strokeEnd”)

    animation.duration = duration

    animation.fromValue = 0

    animation.toValue = 1

    animation.timingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.linear)        

    shapeLayer.strokeEnd = 1.0

    shapeLayer.add(animation, forKey: “animateCircle”)

}

有一个很好的博客例子。