主/图纸视图控制器

Question

我正在开发一个简单的应用程序，允许用户使用四种颜色中的一种进行绘制并共享/导出他们的工作。要更改画笔大小，您必须输入＆＃34;设置＆＃34;通过滑块查看和调整它。我遇到的问题是滑块的值在返回主视图时不会影响画笔的大小。无论我设置初始画笔大小是什么，这就是它如何保持无论多少次我搞乱滑块。
这两个视图由NavigationViewController管理，如果这会产生影响。

主/图纸视图控制器

import UIKit

class DrawingViewController: UIViewController {

@IBOutlet weak var imageView: UIImageView!
@IBOutlet weak var buttonsStackView: UIStackView!

var lastPoint = CGPoint.zero
var red : CGFloat = 0.0
var green : CGFloat = 0.0
var blue : CGFloat = 0.0

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(DrawingViewController.appBecameActive), name: UIApplicationDidBecomeActiveNotification, object: nil)

    blueTapped(UIButton())
}

func appBecameActive() {
    self.buttonsStackView.hidden = false
}

override func viewWillAppear(animated: Bool) {
    self.navigationController?.navigationBarHidden = true
    print("Current Brush Size: \(SettingsViewController().brushSize)")
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    if let touch = touches.first {
        let point = touch.locationInView(self.imageView)
        self.lastPoint = point
    }

    self.buttonsStackView.hidden = true
}

override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    if let touch = touches.first {
        let point = touch.locationInView(self.imageView)
        //print("Point: \(point)")

        drawBetweenPoints(self.lastPoint, secondPoint: point)

        self.lastPoint = point
    }

}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    if let touch = touches.first {
        let point = touch.locationInView(self.imageView)
        //print(point)

        drawBetweenPoints(self.lastPoint, secondPoint: point)
    }

    self.buttonsStackView.hidden = false
}

func drawBetweenPoints(firstPoint:CGPoint, secondPoint:CGPoint) {
    UIGraphicsBeginImageContext(self.imageView.frame.size)
    let context = UIGraphicsGetCurrentContext()

    self.imageView.image?.drawInRect(CGRect(x: 0, y: 0, width: self.imageView.frame.size.width, height: self.imageView.frame.size.height))

    CGContextMoveToPoint(context, firstPoint.x, firstPoint.y)
    CGContextAddLineToPoint(context, secondPoint.x, secondPoint.y)

    //randomTapped(UIButton())
    CGContextSetRGBStrokeColor(context, self.red, self.green, self.blue, 1.0)
    CGContextSetLineCap(context, .Round)
    CGContextSetLineWidth(context, CGFloat(SettingsViewController().brushSize))

    CGContextStrokePath(context)

    self.imageView.image = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()
}

func eraseEasel() {
    self.imageView.image = nil
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "drawingToSettingsSegue" {
        let settingsVC = segue.destinationViewController as! SettingsViewController
        settingsVC.drawingVC = self
    }
}

@IBAction func blueTapped(sender: AnyObject) {
    self.red = 56 / 255
    self.green = 109 / 255
    self.blue = 229 / 255
}
@IBAction func greenTapped(sender: AnyObject) {
    self.red = 37 / 255
    self.green = 235 / 255
    self.blue = 114 / 255
}
@IBAction func redTapped(sender: AnyObject) {
    self.red = 229 / 255
    self.green = 56 / 255
    self.blue = 56 / 255
}
@IBAction func yellowTapped(sender: AnyObject) {
    self.red = 249 / 255
    self.green = 215 / 255
    self.blue = 23 / 255
}
@IBAction func randomTapped(sender: AnyObject) {
    self.red = CGFloat(arc4random_uniform(255)) / 255
    self.green = CGFloat(arc4random_uniform(255)) / 255
    self.blue = CGFloat(arc4random_uniform(255)) / 255
}

}

设置视图控制器

import UIKit

class SettingsViewController: UIViewController {

weak var drawingVC : DrawingViewController? = nil

@IBOutlet weak var brushSlider: UISlider!

var brushSize : Float = 15


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.

    self.navigationController?.navigationBarHidden = false
}

override func viewWillAppear(animated: Bool) {
    brushSlider.value = self.brushSize
}

@IBAction func eraseTapped(sender: AnyObject) {
    self.drawingVC?.eraseEasel()
    self.navigationController?.popViewControllerAnimated(true)
}

@IBAction func shareTapped(sender: AnyObject) {
    if let image = drawingVC?.imageView.image {
        let activityVC = UIActivityViewController(activityItems: [image], applicationActivities: nil)
        self.presentViewController(activityVC, animated: true, completion: nil)
    }
}

@IBAction func brushSlider(sender: AnyObject) {
    self.brushSize = brushSlider.value
    print(self.brushSize)
}

}

Answer 1

您总是会获得新的画笔大小，这是默认值。

SettingsViewController().brushSize

此行创建一个新的SettingsViewController对象，并从中获取brushSize值，即15。

在主视图控制器的顶部创建一个插座，如果要使用在应用程序运行之间不会持续存在的画笔大小的实例，请使用该插座。

var settingsVC = SettingsViewController()

然后替换所有

SettingsViewController().brushSize

带

settingsVC.brushSize

但是，即使执行此操作，您也要从故事板中实例化SettingsViewController对象。这将是一个完全不同的实例，而不是您在主视图控制器顶部创建的实例，直到您转到设置视图，除非它是嵌入的segue。如果您希望初始画笔大小始终为15，并且仅在进入设置屏幕后进行更新，则可以在prepareForSegue

中设置本地参考

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "drawingToSettingsSegue" {
        let settingsVC = segue.destinationViewController as! SettingsViewController
        settingsVC.drawingVC = self
        self.settingsVC = settingsVC
    }
}

祝你好运，希望这会有所帮助！

UISlider滑块值未保存

主/图纸视图控制器

设置视图控制器

1 个答案: