     weak var container: CoursePopupWindow?
     
     
+    // MARK: - Components
+    /// loading指示器
+    private lazy var activityIndicator: UIActivityIndicatorView = {
+        let activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .Gray)
+        activityIndicator.startAnimating()
+        return activityIndicator
+    }()
+    
     // MARK: - Constructed
     override init(frame: CGRect) {
         super.init(frame: frame)

    var models: [CourseModel] = [] {
        didSet {
            if models.count == studentCourses.count {
                dispatch_async(dispatch_get_main_queue()) { [weak self] () -> Void in
                    self?.setupCoursePanels()
                }
            }

    
    // MARK: - Private
    private func configure() {
        self.scrollEnabled = false
        self.pagingEnabled = true
        self.delegate = self
        self.bounces = true
