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

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);
            }
        } 

其他回答

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。

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.

            }
        }

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

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>

使用setWebViewClient()并重写onPageFinished()