ViewPager在setImageResource中返回OOM

Question

在viewpager onPageselected中设置可绘制对象会导致OOM。

.constant

崩溃日志：

//
//  ExpandCollapseTableViewController.swift
//
//  Created by Don Mag on 6/19/18.
//

import UIKit

class ExpandCollapseCell: UITableViewCell {

    @IBOutlet var topLabel: UILabel!
    @IBOutlet var theButton: UIButton!
    @IBOutlet var bottomLabel: UILabel!
    @IBOutlet var theShim: UIView!
    @IBOutlet var shimHeightConstraint: NSLayoutConstraint!

    var myCallBack: (() -> ())?

    @IBAction func didTap(_ sender: Any) {
        myCallBack?()
    }

}

class ExpandCollapseTableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.rowHeight = UITableViewAutomaticDimension
        tableView.estimatedRowHeight = 100
    }

    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 4
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "ExpandCollapseCell", for: indexPath) as! ExpandCollapseCell

        cell.topLabel.text = "Index Path - \(indexPath)"
        cell.bottomLabel.text = "Line 1\nLine 2\nLine 3\nLine 4"

        // init to "collapsed"
        // in actual use, this would be tracked so the row would remain expanded or collapsed
        // on reuse (when the table is scrolled)
        cell.shimHeightConstraint.constant = 0

        if true {
            cell.topLabel.backgroundColor = .clear
            cell.theButton.backgroundColor = .clear
            cell.bottomLabel.backgroundColor = .clear
            cell.theShim.backgroundColor = .clear
        }

        cell.myCallBack = {
            UIView.animate(withDuration: 0.3) { // It must be 0.3
                self.tableView.beginUpdates()
                cell.shimHeightConstraint.constant = (cell.shimHeightConstraint.constant == 0) ? cell.bottomLabel.frame.size.height : 0
                self.tableView.layoutIfNeeded()
                self.tableView.endUpdates()
            }
        }

        return cell
    }

}