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?
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.
}
}
});
}
其他回答
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。 } `
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。
我把NeTeInStEiN的代码简化成这样:
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;
}
}
});
这很容易理解,OnPageFinished如果之前的回调是onpagstarted,所以页面是完全加载的。
你可以通过webview类中的getProgress方法来跟踪进度状态。
初始化进度状态
private int mProgressStatus = 0;
然后AsyncTask像这样加载:
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();
}
}
}
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>