ios - 快速更改 uiimageview 背景颜色

Question

![the result screenshot--][http://i.stack.imgur.com/4YRAJ.png]我想像后面那样改变 ![enter image description here][http://i.stack.imgur.com/cBMsJ.png]当滑动条打开时，我想让滑动条后面的背景变暗以覆盖 UIimageview，但是除了 UIimageView 之外的背景都变暗了。有什么方法可以使图像变暗吗？

   //
    //  ViewController.swift
    //  SideBarMenu
    //
    //  Created by Alexandre on 30/01/2015.
    //  Copyright (c) 2015 Alexandre. All rights reserved.
    //

import UIKit
import Social

class ViewController: UIViewController, SideBarDelegate {

    @IBOutlet weak var backgroundView: UIView!
    @IBOutlet weak var hedgeImage: UIImageView!

    func sideBarWillOpen() {
       /* let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Light)
        let blurView = UIVisualEffectView(effect: blurEffect)
        blurView.frame = CGRectMake(0,0, 200, backgroundView.frame.size.height)
        backgroundView.addSubview(blurView)*/

        backgroundView.backgroundColor    = UIColor.grayColor()
        hedgeImage.backgroundColor = UIColor.grayColor()
    }

    func sideBarWillClose() {
        backgroundView.backgroundColor    = UIColor.whiteColor()
       // hegeImage.backgroundColor = UIColor.whiteColor()
    }

Answer 1

实现这一点的一种方法是，您可以在所有 View 之上再添加一个 View 并将该 View 颜色设置为 grayColor 并在开始时隐藏它并将其 alpha 设置为 0.8 和当侧边栏出现时显示该 View ，当侧边栏隐藏时您可以隐藏该 View 。

这是为您准备的简单示例代码:

import UIKit

class ViewController: UIViewController, sideBarDelegate {

    var sideBar : SideBar = SideBar()

    @IBOutlet weak var TransperentView: UIView!
    @IBOutlet weak var imageView: UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
        TransperentView.hidden = true
        TransperentView.alpha = 0.8
        TransperentView.backgroundColor = UIColor.grayColor()
        sideBar = SideBar(sourceView: self.view, menuIteams: ["FirstIteam","SecondIteam","ThirdIteam","FourthIteam"])
        sideBar.delegate = self
    }

    func sideBarDidSelectButtonAtIndex(index: Int) {

        sideBar.showSideBar(false)
        TransperentView.hidden = true  //hide view
    }
    @IBAction func index(sender: AnyObject) {

        TransperentView.hidden = false
        sideBar.showSideBar(true)   //show view

    }
}

结果将是:

HERE是更多信息的示例项目。