当我在我的标签之间切换时，它会加载几秒钟，我想知道我的数据正在加载。为此，我决定添加一个活动指标。
我写了一个小功能：
func showActivityIndicator() {
dispatch_async(dispatch_get_main_queue()) {
self.spinner = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)
self.spinner.frame = CGRect(x: 0.0, y: 0.0, width: 80.0, height: 80.0)
self.spinner.center = CGPoint(x:self.loadingView.bounds.size.width / 2, y:self.loadingView.bounds.size.height / 2)
self.loadingView.addSubview(self.spinner)
self.view.addSubview(self.loadingView)
self.spinner.startAnimating()
}
}
将显示我的指标。当我从infoController中点击按钮时尝试使用它：
@IBAction func goToMainFromInfo(sender: AnyObject) {
self.showActivityIndicator()
self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
self.hideActivityIndicator()
}
}
我在segue执行之前显示它并隐藏在之后。它对我没有帮助。当我尝试使用同步时：
@IBAction func goToMainFromInfo(sender: AnyObject) {
dispatch_async(dispatch_get_main_queue()) {
self.showActivityIndicator()
self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
self.hideActivityIndicator()
}
}
但它也没有帮助。当我按Tab键时，不透明度变为0.5，我在加载时等待。但我没有看到我的活动指标。
有什么问题？
答案 0 :(得分：50)
试试这个：
var indicator = UIActivityIndicatorView()
func activityIndicator() {
indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
indicator.center = self.view.center
self.view.addSubview(indicator)
}
你想开始动画的地方
indicator.startAnimating()
indicator.backgroundColor = UIColor.whiteColor()
停止：
indicator.stopAnimating()
indicator.hidesWhenStopped = true
注意：避免同时调用start和stop。只是给出一些条件。
答案 1 :(得分：18)
Swift 3.0
// UIView扩展
fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"
public extension UIView {
var activityIndicatorView: UIActivityIndicatorView {
get {
if let activityIndicatorView = getAssociatedObject(&ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
return activityIndicatorView
} else {
let activityIndicatorView = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
activityIndicatorView.activityIndicatorViewStyle = .gray
activityIndicatorView.color = .gray
activityIndicatorView.center = center
activityIndicatorView.hidesWhenStopped = true
addSubview(activityIndicatorView)
setAssociatedObject(activityIndicatorView, associativeKey: &ActivityIndicatorViewAssociativeKey, policy: .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
return activityIndicatorView
}
}
set {
addSubview(newValue)
setAssociatedObject(newValue, associativeKey:&ActivityIndicatorViewAssociativeKey, policy: .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
}
// NSObject扩展
public extension NSObject {
func setAssociatedObject(_ value: AnyObject?, associativeKey: UnsafeRawPointer, policy: objc_AssociationPolicy) {
if let valueAsAnyObject = value {
objc_setAssociatedObject(self, associativeKey, valueAsAnyObject, policy)
}
}
func getAssociatedObject(_ associativeKey: UnsafeRawPointer) -> Any? {
guard let valueAsType = objc_getAssociatedObject(self, associativeKey) else {
return nil
}
return valueAsType
}
}
开始动画
tableView.activityIndicatorView.startAnimating()
停止动画
tableView.activityIndicatorView.stopAnimating()
您可以在Magic
中找到更多代码答案 2 :(得分：14)
Swift 2+
class ViewController: UITableViewController {
weak var activityIndicatorView: UIActivityIndicatorView!
override func viewDidLoad() {
super.viewDidLoad()
let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
tableView.backgroundView = activityIndicatorView
self.activityIndicatorView = activityIndicatorView
activityIndicatorView.startAnimating()
}
...
}
答案 3 :(得分：3)
我使用两种扩展方法将Index mismatch: 168586039d6b675e5ba51706ea759f8ee701a538 != 45485a0f950096c26425196ab7e7fd54c042d4cc
rereading 284599fe3bd0720c7c516191d67031d855d6a3c6
Svndiff data contains backward-sliding source view: Svndiff has backwards-sliding source views at C:/Program Files/Git/mingw64/share/perl5/Git/SVN/Ra.pm line 312.
添加为表视图的UIActivityIndicatorView。
backgroundView您可以像这样显示/隐藏它。
extension UITableView {
func showActivityIndicator() {
DispatchQueue.main.async {
let activityView = UIActivityIndicatorView(style: .medium)
self.backgroundView = activityView
activityView.startAnimating()
}
}
func hideActivityIndicator() {
DispatchQueue.main.async {
self.backgroundView = nil
}
}
}
答案 4 :(得分：2)
此代码可以帮助您:)
let indicator:UIActivityIndicatorView = UIActivityIndicatorView (activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
indicator.color = UIColor .magentaColor()
indicator.frame = CGRectMake(0.0, 0.0, 10.0, 10.0)
indicator.center = self.view.center
self.view.addSubview(indicator)
indicator.bringSubviewToFront(self.view)
indicator.startAnimating()
答案 5 :(得分：2)
SWIFT
将它放在你的班级下面：
let indicator:UIActivityIndicatorView = UIActivityIndicatorView (activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
将它放在你的loadView（）中：
indicator.color = UIColor .magentaColor()
indicator.frame = CGRectMake(0.0, 0.0, 10.0, 10.0)
indicator.center = self.view.center
self.view.addSubview(indicator)
indicator.bringSubviewToFront(self.view)
indicator.startAnimating()
在我的情况下，我通过func请求请求json对象，所以我把它放在该函数的末尾，以便在数据加载后删除活动指示符：
self.indicator.stopAnimating()
self.indicator.hidesWhenStopped = true
答案 6 :(得分：2)
另一种方法，在我的代码中，我为UITableView（Swift 2.3）添加了一个扩展：
extension UITableView {
func activityIndicator(center: CGPoint = CGPointZero, loadingInProgress: Bool) {
let tag = 12093
if loadingInProgress {
var indicator = UIActivityIndicatorView()
indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
indicator.tag = tag
indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.WhiteLarge
indicator.color = //Your color here
indicator.center = center
indicator.startAnimating()
indicator.hidesWhenStopped = true
self.superview?.addSubview(indicator)
}else {
if let indicator = self.superview?.viewWithTag(tag) as? UIActivityIndicatorView { {
indicator.stopAnimating()
indicator.removeFromSuperview()
}
}
}
}
注意：我的tableview嵌入在UIView（superview）
中答案 7 :(得分：1)
print("(a):{}".format(a.get('a'['b'])))
答案 8 :(得分：0)
使用＆＃34; lazy var＆＃34;。它比功能
更好fileprivate lazy var activityIndicatorView: UIActivityIndicatorView = {
let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .gray)
activityIndicatorView.hidesWhenStopped = true
// Set Center
var center = self.view.center
if let navigationBarFrame = self.navigationController?.navigationBar.frame {
center.y -= (navigationBarFrame.origin.y + navigationBarFrame.size.height)
}
activityIndicatorView.center = center
self.view.addSubview(activityIndicatorView)
return activityIndicatorView
}()
只需在任何地方启动微调器
像这样func requestData() {
// Request something
activityIndicatorView.startAnimating()
}
答案 9 :(得分：0)
为了即使在最终的UITableViewController分隔符上也将UIActivityIndicator放在前台，我采用了这种解决方案。
我已经以编程方式添加了UIActivityIndicator，并将其添加为UINavigationController的子视图
var activityIndicator: UIActivityIndicatorView!
override func viewDidLoad() {
super.viewDidLoad()
// Code
// .... omissis
// Set activity indicator
activityIndicator = UIActivityIndicatorView(style: .whiteLarge)
activityIndicator.color = UIColor.darkGray
activityIndicator.center = tableView.center
activityIndicator.hidesWhenStopped = true
activityIndicator.stopAnimating()
self.navigationController?.view.addSubview(activityIndicator)
}
我只是在需要时启动和停止它（对于我而言）：
func animateActivityIndicator(_ sender: Any ) {
guard let vc = sender as? UIViewController else { return }
if let v = vc as? MyTableViewController {
if v.activityIndicator.isAnimating {
v.activityIndicator.stopAnimating()
} else {
v.activityIndicator.startAnimating()
}
}
// Others UIViewController or UITableViewController follows...
// all of them exhibits an activityIndicator variable
// implemented programmatically or with the storyboard
}
PS。我的环境是Xcode 10.0，iOS 12.0
答案 10 :(得分：0)
更新Swift 4.2：
1。调用viewDidLoad上的activityIndicator函数
例如：
var indicator = UIActivityIndicatorView()
override func viewDidLoad() {
//Initializing the Activity Indicator
activityIndicator()
//Starting the Activity Indicator
indicator.startAnimating()
//Call Your WebService or API
callAPI()
}
执行与UI相关的操作或API调用
func callAPI() {
YourModelClass.fetchResult(someParams,
completionHandler: { (response) in
//Do necessary UIUpdates
self.indicator.stopAnimating()
})
}
3。停止活动指示器
func activityIndicator() {
indicator = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
indicator.style = UIActivityIndicatorView.Style.whiteLarge
indicator.color = .red
indicator.center = self.view.center
self.view.addSubview(indicator)
}
答案 11 :(得分：-1)
@brocolli对Swift 4.0的回答。在获取或设置关联对象之前，必须使用 objc _ 。根据文档，在Swift中获取和设置关联对象的API为：
func objc_getAssociatedObject(object: AnyObject!,
key: UnsafePointer<Void>
) -> AnyObject!
func objc_setAssociatedObject(object: AnyObject!,
key: UnsafePointer<Void>,
value: AnyObject!,
policy: objc_AssociationPolicy)
实施：
import UIKit
fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"
extension UIView {
var activityIndicatorView: UIActivityIndicatorView {
get {
if let activityIndicatorView = objc_getAssociatedObject(self, &ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
return activityIndicatorView
} else {
let activityIndicatorView = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
activityIndicatorView.activityIndicatorViewStyle = .gray
activityIndicatorView.color = .gray
activityIndicatorView.center = center
activityIndicatorView.hidesWhenStopped = true
addSubview(activityIndicatorView)
objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, activityIndicatorView, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
return activityIndicatorView
}
}
set {
addSubview(newValue)
objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
}