内存使用量不断增加

Question

I've created a pretty simple test app. It includes a 3 view controllers. The main view controller has a table view, that uses custom cells. The other two view controllers are able to be accessed through the main view controller, each have collection views, and can go back to the main view controller.

Here is the memory issue. Anytime I click on any of the cells from the 3 view controllers, the memory usage increases. I ran the app while using the 'Leaks' profiling template and found no leaks. Also used the 'Allocations' profiling template, checked 2 of the view controllers (recorded the reference counts), and all the stored reference counts under my program were released.

I haven't been able to use the Debug Memory Graph as it keeps crashing Xcode...

Main View Controller

import UIKit

class TableViewController: UITableViewController, UISearchBarDelegate {

    @IBOutlet weak var searchForTool: UISearchBar!
    @IBOutlet weak var toolTable: UITableView!

    var searchActive : Bool = false
    var data = ["  Alphabetical", "  Numerical"]
    var identities = ["A", "B"]

    override func viewDidLoad() {
        super.viewDidLoad()

        toolTable.delegate = self
        toolTable.dataSource = self
    }

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

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


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

        cell.toolLabel.text = data[indexPath.row]
        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        let vcName = identities[indexPath.row]
        let viewController = storyboard?.instantiateViewController(withIdentifier: vcName)
        self.navigationController?.pushViewController(viewController!, animated: true)
    }
}

One of the other View Controllers (both identical)

import UIKit

class AlphabeticalViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    @IBOutlet weak var collectionView: UICollectionView!

    var labelArray = [String]()
    var identities = [String]()

    override func viewDidLoad() {
        super.viewDidLoad()

        labelArray = ["Main", "Definitions", "Steps", "References", "Other"]

        identities = ["C", "B", "B", "D", "E"]

        self.navigationController?.setNavigationBarHidden(true, animated: false)

        collectionView.delegate = self
        collectionView.dataSource = self

    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return labelArray.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)

        let myLabel = cell.viewWithTag(1) as! UILabel

        myLabel.text = labelArray[indexPath.row]

        return cell
    }


    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        let vcName = identities[indexPath.row]
        let viewController = storyboard?.instantiateViewController(withIdentifier: vcName)
        self.navigationController?.pushViewController(viewController!, animated: true)

    }

}

Custom Cell Class

import UIKit

class CustomCell: UITableViewCell {

    @IBOutlet weak var toolLabel: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}

I will provide any other images if needed. Any help would be greatly appreciated.

Information I got using the allocation tool. The commented out code is just a search feature that I don't need atm.

Answer 1

The problem seems to be inside the CustomCell , maybe some resources not deinitialized. Do you have some code inside awakeFromNib() or setSelected(...) ?

Answer 2

You have problem with your tableView and collection view. look at IBOutlets your tableView name is toolTable

@IBOutlet weak var toolTable: UITableView!

but inside your datasource for the tableView you're accessing the wrong tableView

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    // this is the wrong tableView
    /*
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! CustomCell
    */
    // you should use the tableview which you have declared 
    let cell = toolTable.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! CustomCell
    cell.toolLabel.text = data[indexPath.row]
    return cell
}

You have the same problem with your CollectionViewControllers as well.

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    //accessing wrong collectionView
    /*
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
    */
    // here you have to use self because your have named your collectionView the same as collectionView
    let cell = self.collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
    let myLabel = cell.viewWithTag(1) as! UILabel

    myLabel.text = labelArray[indexPath.row]

    return cell
}

Note: Your TableViewController and CollectionViewController are already Controllers. wondering why you have another tableView and collection view IBOutlets. Use one at a time

Answer 3

Firstly, I want to give credit to @totiG for pointing out that the problem could be with the navigation controller, and he was right.

There are other smaller memory issues, but the biggest by far had to do with my navigation. I kept pushing controllers onto the navigation stack, without popping them.

Here is the code for my final solution.

I replaced:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

    let vcName = identities[indexPath.row]
    let viewController = storyboard?.instantiateViewController(withIdentifier: vcName)
    self.navigationController?.pushViewController(viewController!, animated: true)

}

With:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

    if indexPath.row == 0 {
        if let navController = self.navigationController {
            for controller in navController.viewControllers {
                if controller is TableViewController {
                    navController.popToViewController(controller, animated: true)
                }
            }
        }
    } else {

        let vcName = identities[indexPath.row]
        let viewController = storyboard?.instantiateViewController(withIdentifier: vcName)
        self.navigationController?.pushViewController(viewController!, animated: true)
    }
}

So now instead of pushing from controller to controller without popping any of them off of the stack, I pop all of the previous controllers up to the 'TableViewController' when 'Main' is clicked.