Question

我有一个UIWebView，里面我必须加载一个网址。

问题是打开webView内存后发生泄漏。我的意思是我无法消除内存泄漏。

以下是我的代码： -

import UIKit
import Toast_Swift


class WebViewController: UIViewController,UIWebViewDelegate {

//WebView
@IBOutlet weak var webView: UIWebView!

//URL
var strUrl : String? = nil

//Tag
var tag : Int! = 0

//ViewDidLoad
override func viewDidLoad() {
    super.viewDidLoad()

    //Delegate of web view
    webView.delegate = self
    //webView.stringByEvaluatingJavaScript(from: "localStorage.clear();")
    self.webView.loadRequest(URLRequest(url: URL(string: self.strUrl!)!))

    //Loading View
    self.view.makeToastActivity(.center)
}

//MARK :- Web view delegate.
func webViewDidFinishLoad(_ webView: UIWebView) {

    //ToastManager.shared.tapToDismissEnabled = true
    self.view.hideToastActivity()
}

//Button Back Action
@IBAction func btnBack(_ sender: Any) {


    if (tag == 1) {
        webView.delegate = nil
        self.strUrl = ""
        webView.removeCache()
        let gotoCreateView = self.storyboard?.instantiateViewController(withIdentifier: "CreateAccountView") as! CreateAccountView

        self.present(gotoCreateView, animated: true, completion: nil)

    } else {

        webView.delegate = nil
        self.strUrl = ""
        webView.removeCache()
        let gotoAboutUsView = self.storyboard?.instantiateViewController(withIdentifier: "AboutUsView") as! AboutUsView

        self.present(gotoAboutUsView, animated: true, completion: nil)
    }


    /*if (1 == tag)
    {
        webView.delegate = nil
        webView.removeCache()
        let gotoCreateView = self.storyboard?.instantiateViewController(withIdentifier: "CreateAccountView") as! CreateAccountView

        self.present(gotoCreateView, animated: true, completion: nil)

    }

    else
    {
        webView.delegate = nil
        webView.removeCache()
        let gotoAboutUsView = self.storyboard?.instantiateViewController(withIdentifier: "AboutUsView") as! AboutUsView

        self.present(gotoAboutUsView, animated: true, completion: nil)
    }*/
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    webView.delegate = nil
    webView.removeCache()
    webView.delegate = self
    self.webView.reload()
 }
}

extension UIWebView
{
 func removeCache()
 {
    URLCache.shared.removeAllCachedResponses()
    URLCache.shared.diskCapacity = 0
    URLCache.shared.memoryCapacity = 0

    if let cookies = HTTPCookieStorage.shared.cookies {
        for cookie in cookies {
            HTTPCookieStorage.shared.deleteCookie(cookie)
        }
    }
  }
}

如何消除内存泄漏？

由于

Answer 1

除了您的代码，您还需要获得以下几点：

第一件事是尝试不在主视图中添加webView，而不是这样你可以设置alpha或hidden属性。如果您正在使用隐藏属性，那么在取消隐藏时将其委托设置为nil并尝试管理WebView在隐藏时无法在后台运行。
如果您在新的ViewController中显示，那么当我们推送WebView时，请设置其委托并重新加载请求。现在，当你试图从那个视图回来。在弹出之前，将其委托设置为nil，将nil设置为其中使用的所有局部变量。

例如：

在ViewDidLoad上：你正在设置委托，现在当你弹出时，意味着移动到上一个屏幕使用这些代码行：

DispatchQueue.main.async(execute: {

      if self.presentedViewController == nil {
           print("Alert comes up with the intended ViewController")
           var inputTextField = UITextField()

           let textPrompt = UIAlertController(title: "Test", message: "Testing", preferredStyle: .alert)

           textPrompt.addAction(UIAlertAction(title: "Continue", style: .default, handler: {
               (action) -> Void in
               // if the input matches the required text

               let str = inputTextField.text
               if str == requireTextInput {
                    print("right")
               } else {
                    print("wrong")
               }

           }))

           textPrompt.addTextField(configurationHandler: {(textField: UITextField!) in
                textField.placeholder = ""
                inputTextField = textField

            })
            weakSelf?.present(textPrompt, animated: true, completion: nil)
      } else {
            // either the Alert is already presented, or any other view controller
            // is active (e.g. a PopOver)
            // ...
            let thePresentedVC : UIViewController? = self.presentedViewController as UIViewController?
            if thePresentedVC != nil {
                 if let _ : UIAlertController = thePresentedVC as? UIAlertController {
                      print("Alert not necessary, already on the screen !")

              } else {

                      print("Alert comes up via another presented VC, e.g. a PopOver")
              }
            }
       }
})

和

  webView.delegate = nil
  webView.removeCache()

在后退按钮上：

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    webView.delegate = nil
    webView.removeCache() 
    webView.delegate = self
    self.webView.reload()
 }

}

如何使用UIWebView删除内存泄漏？

1 个答案: