我目前正在制作一个圣诞节应用程序,希望在屏幕上“下雪”。
到目前为止,我的代码是这样的:
Snow.swift
import Foundation
import UIKit
@IBDesignable
class Snow:UIView
{
var viewHeight = CGFloat(0)
/*
required init(coder aDecoder: NSCoder) {
//Initilse UIView
super.init(coder: aDecoder)!
}
*/
override func drawRect(rect: CGRect) {
let path = UIBezierPath(ovalInRect: rect)
UIColor.whiteColor().setFill()
path.fill()
}
}
ViewController.swift
@IBDesignable
class ViewController: UIViewController {
@IBInspectable var BgColor:UIColor = UIColor.whiteColor()
var animator: UIDynamicAnimator? = nil;
var gravity = UIGravityBehavior()
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = BgColor
/*listSubviewsOfView(self.view)*/ /*Not needed to answer this*/
var snow = Snow(frame: CGRect(x: 0, y: 0, width: 5, height: 5))
snow.opaque = false
self.view.addSubview(snow)
animator = UIDynamicAnimator(referenceView:self.view);
animator?.addBehavior(gravity)
gravity.addItem(snow)
let direction = CGVectorMake(0.0, 1.0)
gravity.gravityDirection = direction
}
/*Not needed to solve this*/
/*
func listSubviewsOfView(views: UIView) {
var index = 0
let randomNumbers = [Int](1...24).shuffle()
for view in views.subviews
{
if let _ = view.restorationIdentifier
{
view.setValue(String(Int(randomNumbers[index])), forKey: "updateText")
index++
}
if index == randomNumbers.count {
break
}
}
}
*/
}
这是目前的外观(在iPhone 5模拟器中)。 正如您所看到的,
UIView
下落得太快了(像砖头一样下落,而不是像雪花一样)。我该如何让“雪花”慢慢飘落,同时加上风的效果呢?