TableView下拉表头放大 导航栏颜色透明度随着TableView偏移量渐变

TableView 下拉表头放大

导航栏颜色透明度随着TableView偏移量渐变

import UIKit
let KScreen_Width = UIScreen.mainScreen().bounds.size.width
let KScreen_Height = UIScreen.mainScreen().bounds.size.height
let imgHeight : CGFloat = 200

class ViewController: UIViewController {
@IBOutlet weak var tableView: UITableView!
var imageView : UIImageView!

override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.navigationController?.navigationBar.barTintColor = UIColor.init(colorLiteralRed: 240/255, green: 240/255, blue: 100/255, alpha: 1)
self.navigationController?.navigationBar.alpha = 0

let rightButton = UIButton.init(type: .Custom)
rightButton.frame = CGRectMake(KScreen_Width-40, 32, 20, 20)
rightButton .setBackgroundImage(UIImage.init(named: "1"), forState: .Normal)
rightButton.addTarget(self, action: #selector(ViewController.click), forControlEvents: .TouchUpInside)
self.navigationController?.view .addSubview(rightButton)

/**
去除导航栏黑线
*/
if ((self.navigationController?.navigationBar .respondsToSelector(#selector(self.navigationController?.navigationBar.setBackgroundImage(_:forBarMetrics:)))) != nil){
for view in (self.navigationController?.navigationBar.subviews)! as [UIView] {
if view is UIImageView {
for view2 in view.subviews {
if view2 is UIImageView {
view2.hidden = true;
}
}
}
}
}

tableView.contentInset = UIEdgeInsetsMake(imgHeight, 0, 0, 0)
imageView = UIImageView.init(frame: CGRectMake(0, -imgHeight, KScreen_Width, imgHeight))
imageView.image = UIImage.init(named: "1468895691727")
imageView.contentMode = .ScaleAspectFill
tableView .addSubview(imageView)

}

func scrollViewDidScroll(scrollView: UIScrollView)
{
let offsetY  = scrollView.contentOffset.y
let offsetH  = imgHeight + offsetY - 20

if offsetH <= 0 {
imageView?.frame = CGRectMake(0, -imgHeight+offsetH, KScreen_Width, imgHeight-offsetH)
self.navigationController?.navigationBar.alpha = 0
} else {

let min = offsetH/(imgHeight-64) < 1 ? offsetH / (imgHeight-64) : 1

self.navigationController?.navigationBar.alpha = min
}

}

// MARK: - Table view data source

func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 100
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath)
cell.textLabel?.text = String(format: "第%ld行",indexPath.row+1)
// Configure the cell...

return cell
}

//右侧按钮点击
func click() {
print("点击了按钮")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}

}