我正在尝试使用UITableView的高度约束和UIView.animateWithDamping(..)块将其动画化,以使其表现得像下拉菜单。但我遇到了白色背景出现在tableView下方的奇怪问题。
iPhone模拟器显示问题
我已经清除了每个背景颜色,但这并没有帮助太多。
以下是设置dropDownView(一个UIView)的所有子视图的代码:
BOTableView类初始化程序:
iPhone模拟器显示问题
我已经清除了每个背景颜色,但这并没有帮助太多。
以下是设置dropDownView(一个UIView)的所有子视图的代码:
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.elements = []
defaultSetup()
}
private func defaultSetup() {
configureActionButton()
configureTableView()
}
private func configureActionButton() {
actionButton = UIButton(frame: CGRectZero)
actionButton.translatesAutoresizingMaskIntoConstraints = false
addSubview(actionButton)
guard let superview = actionButton.superview else {
assert(false, "ActionButton adding to superview failed.")
return
}
// Constraints
actionButton.constrain(.Leading, .Equal, superview, .Leading, constant: 0, multiplier: 1)?.constrain(.Trailing, .Equal, superview, .Trailing, constant: 0, multiplier: 1)?.constrain(.Top, .Equal, superview, .Top, constant: 0, multiplier: 1)?.constrain(.Bottom, .Equal, superview, .Bottom, constant: 0, multiplier: 1)
// Appearance
actionButton.backgroundColor = UIColor.clearColor()
actionButton.opaque = false
actionButton.contentHorizontalAlignment = .Left
actionButton.contentEdgeInsets = UIEdgeInsets(top: 0, left: 20, bottom: 0, right: 0)
if borderVisible {
actionButton.layer.cornerRadius = 5
actionButton.layer.borderColor = UIColor.blackColor().CGColor
actionButton.layer.borderWidth = 1
actionButton.clipsToBounds = true
}
// Actions
actionButton.addTarget(self, action: "menuAction:", forControlEvents: .TouchUpInside)
}
private func configureTableView() {
tableView = BOTableView(frame: CGRectZero, items: elements, configuration: configuration)
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.delegate = self
tableView.dataSource = self
addSubview(tableView)
guard let tableViewSuperview = tableView.superview else {
assert(false, "TableView adding to superview failed.")
return
}
// Constraints
tableView.constrain(.Trailing, .Equal, tableViewSuperview, .Trailing, constant: 0, multiplier: 1)?.constrain(.Top, .Equal, tableViewSuperview, .Bottom, constant: 0, multiplier: 1)?.constrain(.Leading, .Equal, tableViewSuperview, .Leading, constant: 0, multiplier: 1)
tvHeightConstraint = NSLayoutConstraint(item: tableView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 0)
tableView.addConstraint(tvHeightConstraint)
}
BOTableView类初始化程序:
init(frame: CGRect, items: [String], configuration: BOConfiguration) {
super.init(frame: frame, style: UITableViewStyle.Plain)
self.items = items
self.selectedIndexPath = NSIndexPath(forRow: 0, inSection: 0)
self.configuration = configuration
// Setup table view
self.opaque = false
self.backgroundView?.backgroundColor = UIColor.clearColor()
self.backgroundColor = UIColor.clearColor()
self.separatorColor = UIColor.blackColor()
self.scrollEnabled = false
self.separatorStyle = .SingleLine
self.layer.cornerRadius = 5
self.layer.borderColor = UIColor.blackColor().CGColor
self.layer.borderWidth = 1
self.clipsToBounds = true
}
UIView动画:
private func showMenuWithCompletionBlock(completion: (succeeded: Bool) -> Void) {
delegate?.menuWillShow(self)
let tvHeight = frame.size.height * CGFloat(elements.count)
tvHeightConstraint.constant = tvHeight
UIView.animateWithDuration(0.5, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0.5, options: .CurveEaseInOut, animations: { [weak self] () -> Void in
guard let strongSelf = self else {
completion(succeeded: false)
return
}
strongSelf.layoutIfNeeded()
}, completion: { (finished) -> Void in
if finished {
completion(succeeded: true)
}
})
}
这是用于编程的UIView + Constraints扩展的代码:
extension UIView {
/**
:returns: true if v is in this view's super view chain
*/
public func isSuper(v : UIView) -> Bool
{
for var s : UIView? = self; s != nil; s = s?.superview {
if(v == s) {
return true;
}
}
return false
}
public func constrain(attribute: NSLayoutAttribute, _ relation: NSLayoutRelation, _ otherView: UIView, _ otherAttribute: NSLayoutAttribute, constant: CGFloat = 0.0, multiplier : CGFloat = 1.0) -> UIView?
{
let c = NSLayoutConstraint(item: self, attribute: attribute, relatedBy: relation, toItem: otherView, attribute: otherAttribute, multiplier: multiplier, constant: constant)
if isSuper(otherView) {
otherView.addConstraint(c)
return self
}
else if(otherView.isSuper(self) || otherView == self)
{
self.addConstraint(c)
return self
}
assert(false)
return nil
}
public func constrain(attribute: NSLayoutAttribute, _ relation: NSLayoutRelation, constant: CGFloat, multiplier : CGFloat = 1.0) -> UIView?
{
let c = NSLayoutConstraint(item: self, attribute: attribute, relatedBy: relation, toItem: nil, attribute: .NotAnAttribute, multiplier: multiplier, constant: constant)
self.addConstraint(c)
return self
}
}
当我试图在调试器中调试视图层次结构时,唯一具有白色背景的视图是tableView,但我已经在代码中清除了背景。我还尝试将tableView的backgroundView设置为nil以及backgroundView.backgroundColor设置为clearColor(),但没有任何变化。