这里有一个方法，它允许你注册一个Runnable，一旦一个特定的网页地址完成加载就会被执行。我们将每个可运行对象与Map中对应的URL字符串相关联，并使用WebView的getOriginalUrl()方法来选择适当的回调。

package io.github.cawfree.webviewcallback;

/**
 *  Created by Alex Thomas (@Cawfree), 30/03/2017.
 **/

import android.net.http.SslError;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.webkit.SslErrorHandler;
import android.webkit.WebView;
import android.webkit.WebViewClient;

import java.util.HashMap;
import java.util.Map;

/** An Activity demonstrating how to introduce a callback mechanism into Android's WebView. */
public class MainActivity extends AppCompatActivity {

    /* Member Variables. */
    private WebView               mWebView;
    private Map<String, Runnable> mCallbackMap;

    /** Create the Activity. */
    @Override protected final void onCreate(final Bundle pSavedInstanceState) {
        // Initialize the parent definition.
        super.onCreate(pSavedInstanceState);
        // Set the Content View.
        this.setContentView(R.layout.activity_main);
        // Fetch the WebView.
        this.mWebView     = (WebView)this.findViewById(R.id.webView);
        this.mCallbackMap = new HashMap<>();
        // Define the custom WebClient. (Here I'm just suppressing security errors, since older Android devices struggle with TLS.)
        this.getWebView().setWebViewClient(new WebViewClient() {
            /** Handle when a request has been launched. */
            @Override public final void onPageFinished(final WebView pWebView, final String pUrl) {
                // Determine whether we're allowed to process the Runnable; if the page hadn't been redirected, or if we've finished redirection.
                if(pUrl.equals(pWebView.getOriginalUrl())) {
                    // Fetch the Runnable for the OriginalUrl.
                    final Runnable lRunnable = getCallbackMap().get(pWebView.getOriginalUrl());
                    // Is it valid?
                    if(lRunnable != null) { lRunnable.run(); }
                }
                // Handle as usual.
                super.onPageFinished(pWebView, pUrl);
            }
            /** Ensure we handle SSL state properly. */
            @Override public final void onReceivedSslError(final WebView pWebView, final SslErrorHandler pSslErrorHandler, final SslError pSslError) { pSslErrorHandler.proceed(); }
        });
        // Assert that we wish to visit Zonal's website.
        this.getWebView().loadUrl("http://www.zonal.co.uk/");
        // Align a Callback for Zonal; this will be serviced once the page has loaded.
        this.getCallbackMap().put("http://www.zonal.co.uk/", new Runnable() {     @Override public void run() { /* Do something. */ } });
    }

    /* Getters. */
    public final WebView getWebView() {
        return this.mWebView;
    }

    private final Map<String, Runnable> getCallbackMap() {
        return this.mCallbackMap;
    }

}

我非常倾向于@NeTeInStEiN(和@polen)解决方案，但会用一个计数器来实现它，而不是多个布尔值或状态监视器(只是另一种风格，但我认为可能会共享)。它确实有一个JS的细微差别，但我觉得逻辑是更容易理解一点。

private void setupWebViewClient() {
    webView.setWebViewClient(new WebViewClient() {
        private int running = 0; // Could be public if you want a timer to check.

        @Override
        public boolean shouldOverrideUrlLoading(WebView webView, String urlNewString) {
            running++;
            webView.loadUrl(urlNewString);
            return true;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            running = Math.max(running, 1); // First request move it to 1.
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            if(--running == 0) { // just "running--;" if you add a timer.
                // TODO: finished... if you want to fire a method.
            }
        }
    });
}

这是一个利用Android的JavaScript钩子功能来检测URL何时加载的新方法。使用这种模式，我们利用JavaScript对文档状态的了解在Android运行时内生成一个本机方法调用。这些javascript可访问的调用可以使用@JavaScriptInterface注释进行。

这个实现需要我们在WebView的设置上调用setJavaScriptEnabled(true)，所以它可能不适合取决于你的应用程序的需求，例如安全问题。

src/io/github/cawfree/webviewcallback/MainActivity.java(果冻豆，API级别16)

package io.github.cawfree.webviewcallback;

/**
 *  Created by Alex Thomas (@Cawfree), 30/03/2017.
 **/

import android.net.http.SslError;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.JavascriptInterface;
import android.webkit.SslErrorHandler;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

/** An Activity demonstrating how to introduce a callback mechanism into Android's WebView. */
public class MainActivity extends AppCompatActivity {

    /* Static Declarations. */
    private static final String HOOK_JS             = "Android";
    private static final String URL_TEST            = "http://www.zonal.co.uk/";
    private static final String URL_PREPARE_WEBVIEW = "";

    /* Member Variables. */
    private WebView mWebView = null;

    /** Create the Activity. */
    @Override protected final void onCreate(final Bundle pSavedInstanceState) {
        // Initialize the parent definition.
        super.onCreate(pSavedInstanceState);
        // Set the Content View.
        this.setContentView(R.layout.activity_main);
        // Fetch the WebView.
        this.mWebView = (WebView)this.findViewById(R.id.webView);
        // Enable JavaScript.
        this.getWebView().getSettings().setJavaScriptEnabled(true);
        // Define the custom WebClient. (Here I'm just suppressing security errors, since older Android devices struggle with TLS.)
        this.getWebView().setWebViewClient(new WebViewClient() { @Override     public final void onReceivedSslError(final WebView pWebView, final SslErrorHandler pSslErrorHandler, final SslError pSslError) { pSslErrorHandler.proceed(); } });
        // Define the WebView JavaScript hook.
        this.getWebView().addJavascriptInterface(this, MainActivity.HOOK_JS);
        // Make this initial call to prepare JavaScript execution.
        this.getWebView().loadUrl(MainActivity.URL_PREPARE_WEBVIEW);
    }

    /** When the Activity is Resumed. */
    @Override protected final void onPostResume() {
        // Handle as usual.
        super.onPostResume();
        // Load the URL as usual.
        this.getWebView().loadUrl(MainActivity.URL_TEST);
        // Use JavaScript to embed a hook to Android's MainActivity. (The onExportPageLoaded() function implements the callback, whilst we add some tests for the state of the WebPage so as to infer when to export the event.)
        this.getWebView().loadUrl("javascript:" + "function onExportPageLoaded() { " + MainActivity.HOOK_JS + ".onPageLoaded(); }" + "if(document.readyState === 'complete') { onExportPageLoaded(); } else { window.addEventListener('onload', function () { onExportPageLoaded(); }, false); }");
    }

    /** Javascript-accessible callback for declaring when a page has loaded. */
    @JavascriptInterface @SuppressWarnings("unused") public final void onPageLoaded() {
        // Display the Message.
        Toast.makeText(this, "Page has loaded!", Toast.LENGTH_SHORT).show();
    }

    /* Getters. */
    public final WebView getWebView() {
        return this.mWebView;
    }

}

xml res - - activity_main布局。

<?xml version="1.0" encoding="utf-8"?>
<WebView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/webView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
/>

实际上，我们添加了一个额外的JavaScript函数，用于测试文档的状态。如果它被加载，我们在Android的MainActivity中启动一个自定义的onPageLoaded()事件;否则，我们注册一个事件监听器，一旦页面准备好，使用window更新Android。addEventListener (onload,…);。

因为我们是在调用this. getwebview ().loadURL("")之后追加这个脚本的，所以很可能我们根本不需要“监听”事件，因为我们只有在页面已经加载之后，才有机会通过连续调用loadURL来追加JavaScript钩子。

扩展WebViewClient并调用onPageFinished()如下所示:

mWebView.setWebViewClient(new WebViewClient() {

   public void onPageFinished(WebView view, String url) {
        // do your stuff here
    }
});

用这个应该会有帮助。' var currentUrl = "google.com" var partOfUrl = currentUrl。currentUrl.length-2 substring (0)

webView.setWebViewClient（object： WebViewClient（） {

override fun onLoadResource(WebView view, String url) {
     //call loadUrl() method  here 
     // also check if url contains partOfUrl, if not load it differently.
     if(url.contains(partOfUrl, true)) {
         //it should work if you reach inside this if scope.
     } else if(!(currentUrl.startWith("w", true))) {
         webView.loadurl("www.$currentUrl")

     } else if(!(currentUrl.startWith("h", true))) {
         webView.loadurl("https://$currentUrl")

     } else { ...}


 }

override fun onReceivedSslError(view: WebView?, handler: SslErrorHandler?, error: SslError?) {
   // you can call again loadUrl from here too if there is any error.
}

//你也应该覆盖其他覆盖错误的方法，如onReceiveError，以查看所有这些方法是如何一个接一个地被调用的，以及它们在调试断点时的行为。 ｝ ｀

这将在他开始加载页面之前被调用 (并获得与onFinished()相同的参数)

@Override
public void onPageCommitVisible(WebView view, String url) {
   super.onPageCommitVisible(view, url);
}