如果你想显示一个进度条，你需要监听一个进度变化事件，而不仅仅是页面的完成:

mWebView.setWebChromeClient(new WebChromeClient(){

            @Override
            public void onProgressChanged(WebView view, int newProgress) {

                //change your progress bar
            }


        });

顺便说一句，如果你只想显示一个覆盖onPageFinished方法的Indeterminate ProgressBar就足够了

只是为了显示进度条，“onpagstarted”和“onPageFinished”方法就足够了;但如果你想有一个“is_loading”标志(以及页面重定向，…)，这个方法可以执行非排序，如“onpagstarted > onpagstarted > onPageFinished > onPageFinished”队列。

但与我的短测试(自己测试)，“onProgressChanged”方法值队列是“0-100 > 0-100 > 0-100 >…”

private boolean is_loading = false;

webView.setWebChromeClient(new MyWebChromeClient(context));

private final class MyWebChromeClient extends WebChromeClient{
    @Override
    public void onProgressChanged(WebView view, int newProgress) {
        if (newProgress == 0){
            is_loading = true;
        } else if (newProgress == 100){
            is_loading = false;
        }
        super.onProgressChanged(view, newProgress);
    }
}

如果活动关闭是一个静态变量，也要在活动关闭时设置“is_loading = false”，因为活动可以在页面结束之前完成。

加载url与swiperfreshlayout和ProgressBar: UrlPageActivity.java:

    WebView webView;
    SwipeRefreshLayout _swipe_procesbar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_url_page);


        String url = "http://stackoverflow.com/";

        _swipe_procesbar = (SwipeRefreshLayout)findViewById(R.id.url_path_swipe_procesbar);

        _swipe_procesbar.post(new Runnable() {
                                  @Override
                                  public void run() {
                                      _swipe_procesbar.setRefreshing(true);
                                  }
                              }
        );

        webView = (WebView) findViewById(R.id.url_page_web_view);
        webView.getSettings().setJavaScriptEnabled(true);

        webView.setWebViewClient(new WebViewClient() {
            public void onPageFinished(WebView view, String url) {
                _swipe_procesbar.setRefreshing(false);
                _swipe_procesbar.setEnabled(false);
            }
        });
        webView.loadUrl(url);
    }

activity_url_page.xml:

<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/url_path_swipe_procesbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
        <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context="com.test.test1.UrlPageActivity">


            <WebView
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:id="@+id/url_page_web_view" />
        </RelativeLayout>

</android.support.v4.widget.SwipeRefreshLayout>

谢谢你的回答。它帮助了我，但我必须根据我的需要稍加改进。我有几个页面开始和结束，所以我添加了一个定时器，检查是否在页面结束后开始一个新的页面开始。好吧，糟糕的解释。请参阅代码:)

myWebView.setWebViewClient(new WebViewClient() {
        boolean loadingFinished = true;
        boolean redirect = false;

        long last_page_start;
        long now;

        // Load the url
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            if (!loadingFinished) {
                redirect = true;
            }

            loadingFinished = false;
            view.loadUrl(url);
            return false;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            Log.i("p","pagestart");
            loadingFinished = false;
            last_page_start = System.nanoTime();
            show_splash();
        }

        // When finish loading page
        public void onPageFinished(WebView view, String url) {
            Log.i("p","pagefinish");
            if(!redirect){
                loadingFinished = true;
            }
            //call remove_splash in 500 miSec
            if(loadingFinished && !redirect){
                now = System.nanoTime();
                new android.os.Handler().postDelayed(
                        new Runnable() {
                            public void run() {
                                remove_splash();
                            }
                        },
                        500);
            } else{
                redirect = false;
            }
        }
        private void show_splash() {
            if(myWebView.getVisibility() == View.VISIBLE) {
                myWebView.setVisibility(View.GONE);
                myWebView_splash.setVisibility(View.VISIBLE);
            }
        }
        //if a new "page start" was fired dont remove splash screen
        private void remove_splash() {
            if (last_page_start < now) {
                myWebView.setVisibility(View.VISIBLE);
                myWebView_splash.setVisibility(View.GONE);
            }
        }

});

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
    }
});

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。