[英]How to change the background color of the UIAlertController?
Due to strange behavior of UIActionSheet in iOS 8, I have implemented UIAlertController with UIAction as buttons in it. 由于UIActionSheet在iOS 8中的奇怪行为,我已经将UIAlertController与UIAction一起实现为按钮。 I would like to change the entire background of the UIAlertController.
我想改变UIAlertController的整个背景。 But I can't find any ways to do it.
但我找不到任何办法。
Tried even with, 甚至尝试过,
actionController.view.backgroundColor = [UIColor blackColor];
But didn't help me out. 但是没有帮助我。 Any inputs on this regard will be appreciable.
关于这方面的任何意见都是值得注意的。
Thanks in advance. 提前致谢。
You have to step some views deeper: 你必须深入了解一些观点:
let subview = actionController.view.subviews.first! as UIView
let alertContentView = subview.subviews.first! as UIView
alertContentView.backgroundColor = UIColor.blackColor()
And maybe you want to keep original corner radius: 也许你想保持原来的角半径:
alertContentView.layer.cornerRadius = 5;
Sorry for the "Swifting" but i'm not familiar with Objective-C. 对不起“Swifting”,但我不熟悉Objective-C。 I hope that's similar.
我希望这是类似的。
Of course it's also important to change the title color of the actions. 当然,更改动作的标题颜色也很重要。 Unfortunately I don't know, how to set the color of actions separately.
不幸的是我不知道,如何分别设置动作的颜色。 But this is, how you change all button text colors:
但是,这是如何更改所有按钮文本颜色:
actionController.view.tintColor = UIColor.whiteColor();
The corner radius of the UIAlertController has changed since this answer's been posted! 自这个答案发布以来, UIAlertController的角半径已经改变了! Replace this:
替换这个:
alertContentView.layer.cornerRadius = 5;
to this: 对此:
actionContentView.layer.cornerRadius = 15
maybe you like the use the blur effect in the dark mode. 也许你喜欢在黑暗模式下使用模糊效果。 Here is a very easy way to get this:
这是一个非常简单的方法:
UIVisualEffectView.appearance(whenContainedInInstancesOf: [UIAlertController.classForCoder() as! UIAppearanceContainer.Type]).effect = UIBlurEffect(style: .dark)
I have found a hack-ish way of doing it. 我找到了一种破解方法。 First you need an extension to allow you to search for the
UIVisualEffectView
inside the UIAlertController
: 首先,您需要一个扩展来允许您在
UIVisualEffectView
搜索UIAlertController
:
extension UIView
{
func searchVisualEffectsSubview() -> UIVisualEffectView?
{
if let visualEffectView = self as? UIVisualEffectView
{
return visualEffectView
}
else
{
for subview in subviews
{
if let found = subview.searchVisualEffectsSubview()
{
return found
}
}
}
return nil
}
}
Important : You have to call this function after calling presentViewController
, because only after loading the view controller that the visual effects view is inserted into place. 重要提示 :调用
presentViewController
后必须调用此函数,因为只有在加载视图控制器后才能将视觉效果视图插入到位。 Then you can change the effect associated with it to a dark blur effect: 然后,您可以将与其关联的效果更改为暗模糊效果:
self.presentViewController(actionController, animated: true, completion: nil)
if let visualEffectView = actionController.view.searchVisualEffectsSubview()
{
visualEffectView.effect = UIBlurEffect(style: .Dark)
}
And this is the final result: 这是最终的结果:
I am honestly surprised myself how well it works! 老实说我很惊讶它的工作原理! I think this is probably something Apple forgot to add.
我想这可能是Apple忘记添加的内容。 Also, I haven't yet passed an App through approval with this "hack" (it isn't a hack because we're only using public APIs), but I'm confident there won't be a problem.
此外,我还没有通过与批准通过了一个应用这种“黑客”(这是不是黑客攻击,因为我们只使用公共API),但我相信不会有问题。
Here is a UIAlertController
extension that works on both iPad and iPhone. 这是一个适用于iPad和iPhone的
UIAlertController
扩展。 Cancel button will change from a dark colour to white automatically depending on what blurStyle is selected: 取决于所选的blurStyle,取消按钮将自动从深色变为白色:
extension UIAlertController {
private struct AssociatedKeys {
static var blurStyleKey = "UIAlertController.blurStyleKey"
}
public var blurStyle: UIBlurEffectStyle {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.blurStyleKey) as? UIBlurEffectStyle ?? .extraLight
} set (style) {
objc_setAssociatedObject(self, &AssociatedKeys.blurStyleKey, style, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
view.setNeedsLayout()
view.layoutIfNeeded()
}
}
public var cancelButtonColor: UIColor? {
return blurStyle == .dark ? UIColor(red: 28.0/255.0, green: 28.0/255.0, blue: 28.0/255.0, alpha: 1.0) : nil
}
private var visualEffectView: UIVisualEffectView? {
if let presentationController = presentationController, presentationController.responds(to: Selector(("popoverView"))), let view = presentationController.value(forKey: "popoverView") as? UIView // We're on an iPad and visual effect view is in a different place.
{
return view.recursiveSubviews.flatMap({$0 as? UIVisualEffectView}).first
}
return view.recursiveSubviews.flatMap({$0 as? UIVisualEffectView}).first
}
private var cancelActionView: UIView? {
return view.recursiveSubviews.flatMap({
$0 as? UILabel}
).first(where: {
$0.text == actions.first(where: { $0.style == .cancel })?.title
})?.superview?.superview
}
public convenience init(title: String?, message: String?, preferredStyle: UIAlertControllerStyle, blurStyle: UIBlurEffectStyle) {
self.init(title: title, message: message, preferredStyle: preferredStyle)
self.blurStyle = blurStyle
}
open override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
visualEffectView?.effect = UIBlurEffect(style: blurStyle)
cancelActionView?.backgroundColor = cancelButtonColor
}
}
The following UIView
extension is also needed: 还需要以下
UIView
扩展:
extension UIView {
var recursiveSubviews: [UIView] {
var subviews = self.subviews.flatMap({$0})
subviews.forEach { subviews.append(contentsOf: $0.recursiveSubviews) }
return subviews
}
}
Example: 例:
let controller = UIAlertController(title: "Dark Alert Controller", message: nil, preferredStyle: .actionSheet, blurStyle: .dark)
// Setup controller actions etc...
present(controller, animated: true, completion: nil)
iPhone: 苹果手机:
iPad: iPad的:
Step into one more layer compare with swift2 再加上一层与swift2比较
let subview1 = alert.view.subviews.first! as UIView
let subview2 = subview1.subviews.first! as UIView
let view = subview2.subviews.first! as UIView
subview.backgroundColor = backgroundColor
view.backgroundColor = backgroundColor
view.layer.cornerRadius = 10.0
// set color to UILabel font
setSubviewLabelsToTextColor(textColor, view: view)
// set font to alert via KVC, otherwise it'll get overwritten
let titleAttributed = NSMutableAttributedString(
string: alert.title!,
attributes: [NSFontAttributeName:UIFont.boldSystemFont(ofSize: 17)])
alert.setValue(titleAttributed, forKey: "attributedTitle")
let messageAttributed = NSMutableAttributedString(
string: alert.message!,
attributes: [NSFontAttributeName:UIFont.systemFont(ofSize: 13)])
alert.setValue(messageAttributed, forKey: "attributedMessage")
// set the buttons to non-blue, if we have buttons
if let buttonColor = buttonColor {
alert.view.tintColor = buttonColor
}
func Alert(View: ViewController, Title: String, TitleColor: UIColor, Message: String, MessageColor: UIColor, BackgroundColor: UIColor, BorderColor: UIColor, ButtonColor: UIColor) {
let TitleString = NSAttributedString(string: Title, attributes: [NSFontAttributeName : UIFont.systemFontOfSize(15), NSForegroundColorAttributeName : TitleColor])
let MessageString = NSAttributedString(string: Message, attributes: [NSFontAttributeName : UIFont.systemFontOfSize(15), NSForegroundColorAttributeName : MessageColor])
let alertController = UIAlertController(title: Title, message: Message, preferredStyle: .Alert)
alertController.setValue(TitleString, forKey: "attributedTitle")
alertController.setValue(MessageString, forKey: "attributedMessage")
let okAction = UIAlertAction(title: "OK", style: .Default) { (action) in
}
let cancelAction = UIAlertAction(title: "Cancel", style: .Default, handler: nil)
alertController.addAction(okAction)
alertController.addAction(cancelAction)
let subview = alertController.view.subviews.first! as UIView
let alertContentView = subview.subviews.first! as UIView
alertContentView.backgroundColor = BackgroundColor
alertContentView.layer.cornerRadius = 10
alertContentView.alpha = 1
alertContentView.layer.borderWidth = 1
alertContentView.layer.borderColor = BorderColor.CGColor
//alertContentView.tintColor = UIColor.whiteColor()
alertController.view.tintColor = ButtonColor
View.presentViewController(alertController, animated: true) {
// ...
}
}
For Objective - C Code May be Like. 对于Objective - C Code可能是喜欢的。
UIAlertController * alert=[UIAlertController alertControllerWithTitle:@"Title"
message:@"Message"
preferredStyle:UIAlertControllerStyleAlert];
UIView *firstSubview = alert.view.subviews.firstObject;
UIView *alertContentView = firstSubview.subviews.firstObject;
for (UIView *subSubView in alertContentView.subviews) {
subSubView.backgroundColor = [UIColor colorWithRed:255/255.0f green:255/255.0f blue:255/255.0f alpha:1.0f];
}
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action){
//Close Action
}];
[alert addAction:cancelAction];
[self presentViewController:alert animated:YES completion:nil];
The best decision that i found (without white spots on the sides) 我找到的最佳决定(两侧没有白点)
Link to original answer by Vadim Akhmerov 链接到 Vadim Akhmerov的 原始答案
Answer: 回答:
It is easier to subclass UIAlertController
. UIAlertController
子类UIAlertController
更容易。
The idea is to traverse through view hierarchy each time viewDidLayoutSubviews
gets called, remove effect for UIVisualEffectView
's and update their backgroundColor
: 我的想法是每次调用
viewDidLayoutSubviews
时遍历视图层次结构,删除UIVisualEffectView
的效果并更新其backgroundColor
:
class AlertController: UIAlertController {
/// Buttons background color.
var buttonBackgroundColor: UIColor = .darkGray {
didSet {
// Invalidate current colors on change.
view.setNeedsLayout()
}
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Traverse view hierarchy.
view.allViews.forEach {
// If there was any non-clear background color, update to custom background.
if let color = $0.backgroundColor, color != .clear {
$0.backgroundColor = buttonBackgroundColor
}
// If view is UIVisualEffectView, remove it's effect and customise color.
if let visualEffectView = $0 as? UIVisualEffectView {
visualEffectView.effect = nil
visualEffectView.backgroundColor = buttonBackgroundColor
}
}
// Update background color of popoverPresentationController (for iPads).
popoverPresentationController?.backgroundColor = buttonBackgroundColor
}
}
extension UIView {
/// All child subviews in view hierarchy plus self.
fileprivate var allViews: [UIView] {
var views = [self]
subviews.forEach {
views.append(contentsOf: $0.allViews)
}
return views
}
}
Usage: 用法:
let testAlertController = AlertController(title: nil, message: nil, preferredStyle: .actionSheet) 让testAlertController = AlertController(title:nil,message:nil,preferredStyle:.actionSheet)
var buttonBackgroundColor: UIColor = .darkGray var buttonBackgroundColor:UIColor = .darkGray
You can use the appearance proxy. 您可以使用外观代理。
[[UIView appearanceWhenContainedIn:[UIAlertController class], nil] setBackgroundColor:[UIColor blackColor]];
This seems to apply for all but the cancel action when presenting as an action sheet. 这似乎适用于除了作为动作表提交时的取消操作。
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