Android WebView 显示旧 URL

Question

我有一个 webView 和 3 个按钮，显示 3 个不同的 url。如果我按下显示 url_1 的第一个按钮，当我按下后退按钮并完成它并返回到 Activity 时，一切都很好。但是，当我按第二个按钮显示 url_2 时，会短暂出现 url_1，然后出现 url_2。当我按下后退按钮时，它从 url_2 转到 url_1，然后返回到活动。无论我按下按钮的顺序如何，都会发生此问题，这意味着如果我按下 url_3 的第三个按钮，每当我按下其他 2 个按钮时，在它们的 url 显示之前，它 (url_1) 总是会首先短暂出现。

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    binding.button1.setOnClickListener {
        loadWebViewWith("first_url")
    }

    binding.button2.setOnClickListener {
        loadWebViewWith("second_url")
    }

    binding.button3.setOnClickListener {
        loadWebViewWith("third_url")
    }
}

fun loadWebViewWith(urlStr: String) {

    binding.webView.visibility = View.VISIBLE // shows the webView in the current activity

    binding.webView.settings.javaScriptEnabled = true
    binding.webView.settings.loadWithOverviewMode = true
    binding.webView.settings.useWideViewPort = true

    clearWebViewCache()
    
    binding.webView.webViewClient = object : WebViewClient() {

        override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest? ): Boolean {
            request?.url?.let {
                view?.loadUrl(it.toString())
            }
            return true
        }

        @Deprecated("Deprecated in Java")
        override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
            url?.let {
                view?.loadUrl(it)
            }
            return true
        }
    }

    binding.webView.loadUrl(urlStr)
}

override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
    if (event.getAction() === KeyEvent.ACTION_DOWN) {
        when (keyCode) {
            KeyEvent.KEYCODE_BACK -> {
                if (binding.webView.canGoBack()) {
                    binding.webView.goBack()
                } else {

                    binding.webView.visibility = View.GONE // hides the webView in the current activity
                    clearWebViewCache()
                }
                return true
            }
        }
    }
    return super.onKeyDown(keyCode, event)
}

fun clearWebViewCache() { // I tried these in different combinations

    binding.webView.clearCache(true)
    binding.webView.clearFormData()
    binding.webView.clearHistory()
    binding.webView.clearSslPreferences()

    binding.webView.loadUrl("about:blank")
    binding.webView.reload()

    binding.webView.settings.cacheMode = WebSettings.LOAD_NO_CACHE

    WebStorage.getInstance().deleteAllData()

    CookieManager.getInstance().removeAllCookies(null)
    CookieManager.getInstance().flush()

    this.deleteDatabase("webview.db")
    this.deleteDatabase("webviewCache.db")
}

Answer 1

在 webViewClient 的 onPageFinished 方法中调用 webView.clearHistory() 。

在顶层创建一个布尔变量。

    lateinit var button1 : Button
    lateinit var button2 : Button
    lateinit var button3 : Button
    lateinit var webView: WebView
    var canClear : Boolean = false

加载 url 后将其设置为 true。

        button1.setOnClickListener {
            loadWebViewWith("url")
            canClear = true
        }

        button2.setOnClickListener {
            loadWebViewWith("url")
            canClear = true
        }

        button3.setOnClickListener {
            loadWebViewWith("url")
            canClear = true
        }

覆盖 onPageFinished 函数

            override fun onPageFinished(view: WebView?, url: String?) {
                super.onPageFinished(view, url)
                if(canClear){
                    canClear = false
                    view?.clearHistory()
                }

            }