Question

我有一个WebView正在从互联网上加载一个页面。我希望在加载完成之前显示ProgressBar。

如何监听WebView的页面加载完成情况？

Answer 1

扩展WebViewClient并按如下方式调用onPageFinished（）：

mWebView.setWebViewClient(new WebViewClient() {

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

Answer 2

@ian这不是100％准确。如果页面中有多个iframe，则会有多个onPageFinished（和onPageStarted）。如果你有几个重定向，它也可能会失败。这种方法（几乎）解决了所有问题：

boolean loadingFinished = true;
boolean redirect = false;

mWebView.setWebViewClient(new WebViewClient() {

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String urlNewString) {
        if (!loadingFinished) {
            redirect = true;
        }

        loadingFinished = false;
        webView.loadUrl(urlNewString);
        return true;
    }

    @Override
    public void onPageStarted(WebView view, String url) {
        loadingFinished = false;
        //SHOW LOADING IF IT ISNT ALREADY VISIBLE  
    }

    @Override
    public void onPageFinished(WebView view, String url) {
        if (!redirect) {
           loadingFinished = true;
            //HIDE LOADING IT HAS FINISHED
        } else {
            redirect = false; 
        }
    }
});

<强>更新

根据文件：当嵌入框架的内容发生变化时，不会调用onPageStarted，即单击目标为iframe的链接。

我在Twitter上发现了一个特定的案例，其中只有一个pageFinished被调用并且稍微搞乱了逻辑。为了解决这个问题，我添加了一个计划任务，在X秒后删除加载。在所有其他情况下都不需要这样做。

更新2 ：

现在使用当前的Android WebView实现：

boolean loadingFinished = true;
boolean redirect = false;

    mWebView.setWebViewClient(new WebViewClient() {

        @Override
        public boolean shouldOverrideUrlLoading(
                WebView view, WebResourceRequest request) {
            if (!loadingFinished) {
               redirect = true;
            }

            loadingFinished = false;
            webView.loadUrl(request.getUrl().toString());
            return true;
        }

        @Override
        public void onPageStarted(
                WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
            loadingFinished = false;
            //SHOW LOADING IF IT ISNT ALREADY VISIBLE  
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            if (!redirect) {
               loadingFinished = true;
                //HIDE LOADING IT HAS FINISHED
            } else {
                redirect = false; 
            }
        }
    });

Answer 3

我非常偏爱@NeTeInStEiN（和@polen）解决方案但是会用计数器实现它而不是多个布尔或州观察者（只是另一种味道，但我认为可能会分享）。它确实有一个关于它的JS细微差别，但我觉得逻辑更容易理解。

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.
            }
        }
    });
}

Answer 4

我将NeTeInStEiN的代码简化为：

mWebView.setWebViewClient(new WebViewClient() {
        private int       webViewPreviousState;
        private final int PAGE_STARTED    = 0x1;
        private final int PAGE_REDIRECTED = 0x2;

        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String urlNewString) {
            webViewPreviousState = PAGE_REDIRECTED;
            mWebView.loadUrl(urlNewString);
            return true;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
            webViewPreviousState = PAGE_STARTED;
            if (dialog == null || !dialog.isShowing())
                dialog = ProgressDialog.show(WebViewActivity.this, "", getString(R.string.loadingMessege), true, true,
                        new OnCancelListener() {

                            @Override
                            public void onCancel(DialogInterface dialog) {
                                // do something
                            }
                        });
        }

        @Override
        public void onPageFinished(WebView view, String url) {

            if (webViewPreviousState == PAGE_STARTED) {
                dialog.dismiss();
                dialog = null;
            }

        }
 });

很容易理解，OnPageFinished如果前一个回调是在onPageStarted上，那么页面就完全加载了。

Answer 5

如果您想要显示进度条，则需要监听进度更改事件，而不仅仅是完成页面：

mWebView.setWebChromeClient(new WebChromeClient(){

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

                //change your progress bar
            }


        });

BTW如果你想显示一个不确定的ProgressBar覆盖方法onPageFinished就够了

Answer 6

我发现了一个优雅的解决方案，但是没有经过严格的测试：

public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            if (m_webView.getProgress() == 100) {
                progressBar.setVisibility(View.GONE);
                m_webView.setVisibility(View.VISIBLE);
            }
        }

Answer 7

使用setWebViewClient()并覆盖onPageFinished()

Answer 8

您可以通过getProgress课程中的webview方法跟踪进度状态。

初始化进度状态

private int mProgressStatus = 0;

然后像这样加载AsyncTask：

private class Task_News_ArticleView extends AsyncTask<Void, Void, Void> {
    private final ProgressDialog dialog = new ProgressDialog(
            your_class.this);

    // can use UI thread here
    protected void onPreExecute() {
        this.dialog.setMessage("Loading...");
        this.dialog.setCancelable(false);
        this.dialog.show();
    }

    @Override
    protected Void doInBackground(Void... params) {
        try {
            while (mProgressStatus < 100) {
                mProgressStatus = webview.getProgress();

            }
        } catch (Exception e) {

        }
        return null;

    }

    protected void onPostExecute(Void result) {
        if (this.dialog.isShowing()) {
            this.dialog.dismiss();
        }
    }
}

Answer 9

感谢您的回答。它帮助了我，但我必须根据我的需要改进它。我有几个页面和完成，所以我添加了一个计时器，检查是否启动了pagefinish新的pagestart。好的，不好的解释。见代码：）

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);
            }
        }

});

Answer 10

Kotlin 解决方案

第一个解决方案

class MainActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val webView : WebView = findViewById(R.id.webView)
    webView.webViewClient = MyWebViewClient()
 }

private class MyWebViewClient : WebViewClient() {
    override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
        println("Load Started")
    }
    override fun onPageFinished(view: WebView, url: String) {
        println("Load Finished")
    }
  }
}

第二种解决方案

class MainActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val webView : WebView = findViewById(R.id.webView)
    webView.webViewClient = object : WebViewClient() {
        override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
            println("Load Started")
        }
        override fun onPageFinished(view: WebView, url: String) {
            println("Load Finished")
        }
     }
 }

<块引用>

迟到总比不到好

Answer 11

这是一种利用Android's capability for JavaScript hooks加载URL时检测到的新方法。使用此模式，我们利用JavaScript对文档状态的了解，在Android运行时中生成本机方法调用。这些可通过JavaScript访问的调用可以使用@JavaScriptInterface注释进行。

此实施要求我们在setJavaScriptEnabled(true)的设置上调用WebView，因此可能不适合，具体取决于您的应用程序的要求，例如：安全问题。

src / io / github / cawfree / webviewcallback / MainActivity.java （Jelly Bean，API Level 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;
    }

}

<强> RES /布局/ activity_main.xml中

<?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"
/>

基本上，我们附加了一个额外的JavaScript函数，用于测试文档的状态。如果已加载，我们会在Android的onPageLoaded()中启动自定义MainActivity事件。否则，我们会在页面准备好后使用window.addEventListener('onload', ...);注册一个更新Android的事件监听器。

由于我们在调用this.getWebView().loadURL("")之后附加了此脚本，因此我们可能根本不需要'listen'来处理事件，因为我们只有在页面加载后，才能通过连续调用loadURL来附加JavaScript钩子。

Answer 12

这是一种方法，允许您在特定网址完成加载后注册要执行的Runnable。我们将每个String与Map中的相应网址WebView相关联，并使用getOriginalUrl()的{{1}}方法选择相应的回调

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;
    }

}

Answer 13

只是为了显示进度条，＆＃34; onPageStarted＆＃34;和＆＃34; onPageFinished＆＃34;方法就足够了;但是如果你想要一个＆＃34; is_loading＆＃34; flag（以及页面重定向，...），此方法可以使用非顺序执行，例如＆＃34; onPageStarted＆gt; onPageStarted＆gt; onPageFinished＆gt; onPageFinished＆＃34;队列中。

但是我的短测试（自己测试），＆＃34; onProgressChanged＆＃34;方法值队列是＆＃34; 0-100＆gt; 0-100＆gt; 0-100＆gt; ...＆＃34;

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);
    }
}

同时设置＆＃34; is_loading = false＆＃34; on activity close，如果它是一个静态变量，因为活动可以在页面完成之前完成。

Answer 14

对于Kotlin用户：

webView.webViewClient = object : WebViewClient() {
            override fun onPageFinished(view: WebView?, url: String?) {
                // do your logic
            }
        }

您可以通过许多方法来覆盖

Answer 15

调用OnPageFinshed方法或进度达到100％时，渲染器将无法完成渲染，因此这两种方法都不能保证您已完全渲染视图。

但是您可以从OnLoadResource方法中找出已经渲染的内容和仍在渲染的内容。而且此方法被调用了几次。

        @Override
        public void onLoadResource(WebView view, String url) {
            super.onLoadResource(view, url);
           // Log and see all the urls and know exactly what is being rendered and visible. If you wanna know when the entire page is completely rendered, find the last url from log and check it with if clause and implement your logic there.
            if (url.contains("assets/loginpage/img/ui/forms/")) {
                // loginpage is rendered and visible now.
               // your logic here.

            }
        }

Answer 16

使用它应有帮助。`varcurrentUrl =“ google.com” var partOfUrl = currentUrl.substring（0，currentUrl.length-2）

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.
}

///您还应该重写其他覆盖方法以解决错误，例如onReceiveError，以查看如何依次调用所有这些方法以及在使用断点进行调试时它们的行为方式。 } `

Answer 17

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);
}

Answer 18

使用class Customer { private: long arrive; int processtime; public: Customer() { arrive = processtime = 0; } void set(long when); long when() const { return arrive; } int ptime() const { return processtime; } }; typedef Customer Item; class Queue { private: struct Node { Item item; struct Node * next; }; enum { Q_SIZE = 10 }; Node * front; Node * rear; int items; const int qsize; Queue(const Queue & q) : qsize(0) { } Queue & operator=(const Queue & q) { return *this; } public: Queue(int qs = Q_SIZE); ~Queue(); bool isempty() const; bool isfull() const; int queuecount() const; bool enqueue(const Item &item); bool dequeue(Item &item); }; Queue::Queue(int qs) : qsize(qs) { front = rear = NULL; items = 0; } Queue::~Queue() { Node * temp; while (front != NULL) { temp = front; front = front->next; delete temp; } } bool Queue::enqueue(const Item & item) { if (isfull()) return false; Node * add = new Node; if (add == NULL) return false; add->item = item; add->next = NULL; items++; if (front == NULL) front = add; else rear->next = add; rear = add; return true; } bool Queue::dequeue(Item & item) { if (front == NULL) return false; item = front->item; // Is it necessary and what does it do ? items--; Node * temp = front; front = front->next; delete temp; if (items == 0) rear = NULL; return true; }和SwipeRefreshLayout加载网址：

的 UrlPageActivity.java：

ProgressBar

<强> activity_url_page.xml：

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); }

如何监听WebView完成加载URL？

18 个答案: