我有一个WebView正在从互联网加载一个页面。我想显示一个ProgressBar,直到加载完成。

我如何监听WebView页面加载的完成?


当前回答

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

其他回答

当onpagefinished方法被调用或者进度达到100%时,渲染器将不会完成渲染,所以这两个方法都不能保证视图被完全渲染。

但是你可以从OnLoadResource方法中找出什么已经被渲染了什么还在渲染。这个方法被调用了很多次。

        @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.

            }
        }

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);
            }
        }

});

我发现了一个优雅的解决方案,虽然没有严格测试:

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

对于Kotlin用户:

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

有很多方法你可以重写

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>