Swift

Question

我已经为 UISlider 创建了自定义控件。这个 UISlider 有 2 个拇指，所以它可以找到最小值和最大值。我把这些教程作为我的参考。

编译成功，但我的 UISlider 看起来很奇怪。您可以在此处查看我的 github 存储库。

https://github.com/datomnurdin/RevivalxSwiftSlider

我的 UISlider 自定义控件

import UIKit

class RangeSlider: UIControl {

    var minimumValue: Float!
    var maximumValue: Float!
    var minimumRange: Float!
    var selectedMinimumValue: Float!
    var selectedMaximumValue: Float!

    var distanceFromCenter: Float!

    var _padding: Float!

    var _maxThumbOn: Bool!
    var _minThumbOn: Bool!

    var _minThumb = UIImageView()
    var _maxThumb = UIImageView()
    var _track = UIImageView()
    var _trackBackground = UIImageView()

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

        _minThumbOn = false;
        _maxThumbOn = false;
        _padding = 20;

        let _trackBackground = UIImageView(image: UIImage(named: "bar-background.png"))
        _trackBackground.center = self.center;
        self.addSubview(_trackBackground)

        let _track = UIImageView(image: UIImage(named: "bar-highlight.png"))
        _track.center = self.center
        self.addSubview(_track)


        let _minThumb = UIImageView(image: UIImage(named: "handle.png"), highlightedImage: UIImage(named: "handle-hover.png"))
        _minThumb.frame = CGRectMake(0,0, self.frame.size.height,self.frame.size.height);
        _minThumb.contentMode = UIViewContentMode.Center
        self.addSubview(_minThumb)

        let _maxThumb = UIImageView(image: UIImage(named: "handle.png"), highlightedImage: UIImage(named: "handle-hover.png"))
        _maxThumb.frame = CGRectMake(0,0, self.frame.size.height,self.frame.size.height)
        _maxThumb.contentMode = UIViewContentMode.Center
        self.addSubview(_maxThumb)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }


    override func layoutSubviews() {


        _minThumb.center = CGPointMake(CGFloat(self.xForValue(selectedMinimumValue)), self.center.y);

        _maxThumb.center = CGPointMake(CGFloat(self.xForValue(selectedMaximumValue)), self.center.y)

        NSLog("Tapable size %f", _minThumb.bounds.size.width);
        self.updateTrackHighlight()

    }

    func xForValue(value: Float) -> Float {
        return (Float(self.frame.size.width) - (_padding * 2)) * ((value - minimumValue) / (maximumValue - minimumValue)) + _padding
    }

    func valueForX(x: Float) -> Float {
        return minimumValue + (x - _padding) / (Float(self.frame.size.width) - (_padding * 2)) * (maximumValue - minimumValue)
    }

    func continueTrackingWithTouch(touch: UITouch, event: UIEvent) -> Bool {
        if !_minThumbOn && !_maxThumbOn {
            return true
        }

        var touchPoint: CGPoint = touch.locationInView(self)


        if (_minThumbOn != nil) {
            _minThumb.center = CGPointMake(max(CGFloat(self.xForValue(minimumValue)),min(touchPoint.x - CGFloat(distanceFromCenter), CGFloat(self.xForValue(selectedMaximumValue - minimumRange)))),CGFloat(_minThumb.center.y))
            selectedMinimumValue = self.valueForX(Float(_minThumb.center.x))
        }

        if (_maxThumbOn != nil) {
            _maxThumb.center = CGPointMake(min(CGFloat(self.xForValue(maximumValue)), max(touchPoint.x - CGFloat(distanceFromCenter), CGFloat(self.xForValue(selectedMinimumValue + minimumRange)))), CGFloat(_maxThumb.center.y))
            selectedMaximumValue = self.valueForX(Float(_maxThumb.center.x))
        }

        self.updateTrackHighlight()
        self.setNeedsLayout()

        self.sendActionsForControlEvents(UIControlEvents.ValueChanged)
        return true
    }

    func beginTrackingWithTouch(touch: UITouch, event: UIEvent) -> Bool {
        var touchPoint: CGPoint = touch.locationInView(self)

        if(CGRectContainsPoint(_minThumb.frame, touchPoint)){
            _minThumbOn = true;
            distanceFromCenter = Float(touchPoint.x - _minThumb.center.x)
        }
        else if(CGRectContainsPoint(_maxThumb.frame, touchPoint)){
            _maxThumbOn = true;
            distanceFromCenter = Float(touchPoint.x - _maxThumb.center.x)

        }
        return true;


    }

    func endTrackingWithTouch(touch: UITouch, event: UIEvent) {
        _minThumbOn = false;
        _maxThumbOn = false;
    }

    func updateTrackHighlight() {
        _track.frame = CGRectMake(
        _minThumb.center.x,
        _track.center.y - (_track.frame.size.height/2),
        _maxThumb.center.x - _minThumb.center.x,
        _track.frame.size.height
        );
    }


}

我的输出

应该是这样的

我该如何解决这个问题？

Answer 1

你的问题出在'let'。

_minThumb = UIImageView(image: UIImage(named: "handle.png"), highlightedImage: UIImage(named: "handle-hover.png"))
    _minThumb.frame = CGRectMake(0,0, self.frame.size.height,self.frame.size.height);
    _minThumb.contentMode = UIViewContentMode.Center
    self.addSubview(_minThumb)

     _maxThumb = UIImageView(image: UIImage(named: "handle.png"), highlightedImage: UIImage(named: "handle-hover.png"))
    _maxThumb.frame = CGRectMake(0,0, self.frame.size.height,self.frame.size.height)
    _maxThumb.contentMode = UIViewContentMode.Center
    self.addSubview(_maxThumb)

只需删除 'let' 它应该可以工作，这是因为您正在全局使用 _minThumb 和 _maxThumb，但您将两者声明为常量，因此它们一旦初始化就不会响应任何更改。

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