有用的链接

WebView使用方式

<?xml version="1.0" encoding="utf-8"?>
<WebView xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/webview"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
/>
//加载网页
WebView myWebView = (WebView) findViewById(R.id.webview);
myWebView.loadUrl("http://www.example.com");
//添加网络权限
<manifest ... >
 <uses-permission android:name="android.permission.INTERNET" />
 ...
</manifest>

WebView常用方法总结

注意部分

WebView myWebView = (WebView) findViewById(R.id.webview);
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);

public class WebAppInterface {
 Context mContext;
 /** Instantiate the interface and set the context */
 WebAppInterface(Context c) {
 mContext = c;
 }
 /** Show a toast from the web page */
 @JavascriptInterface
 public void showToast(String toast) {
 Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
 }
}
WebView webView = (WebView) findViewById(R.id.webview);
webView.addJavascriptInterface(new WebAppInterface(this), "Android");
javascript
<input type="button" value="Say hello" onClick="showAndroidToast('Hello Android!')" />
<script type="text/javascript">
 function showAndroidToast(toast) {
 Android.showToast(toast);
 }
</script>

WebView myWebView = (WebView) findViewById(R.id.webview);
myWebView.setWebViewClient(new WebViewClient());
private class MyWebViewClient extends WebViewClient {
 @Override
 public boolean shouldOverrideUrlLoading(WebView view, String url) {
 /** false: 在webview中处理, true: android自行处理 */
 if (Uri.parse(url).getHost().equals("www.example.com")) {
 // This is my web site, so do not override; let my WebView load the page
 return false;
 }
 // Otherwise, the link is not for a page on my site, so launch another Activity that handles URLs
 Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
 startActivity(intent);
 return true;
 }
}

When your WebView overrides URL loading, it automatically accumulates a history of visited web pages. You can navigate backward and forward through the history with goBack() and goForward().
For example, here's how your Activity can use the device Back button to navigate backward:
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
 // Check if the key event was the Back button and if there's history
 if ((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack()) {
 myWebView.goBack();
 return true;
 }
 // If it wasn't the Back key or there's no web page history, bubble up to the default
 // system behavior (probably exit the activity)
 return super.onKeyDown(keyCode, event);
}
The canGoBack() method returns true if there is actually web page history for the user to visit. Likewise, you can use canGoForward() to check whether there is a forward history. If you don't perform this check, then once the user reaches the end of the history, goBack() or goForward() does nothing.

<manifest>
 <meta-data android:name="android.webkit.WebView.EnableSafeBrowsing"
 android:value="true" />
 ...
 <application> ... </application>
</manifest>

public class MyRendererTrackingWebViewClient extends WebViewClient {
 private WebView mWebView;
 @Override
 public boolean onRenderProcessGone(WebView view,
 RenderProcessGoneDetail detail) {
 if (!detail.didCrash()) {
 // Renderer was killed because the system ran out of memory.
 // The app can recover gracefully by creating a new WebView instance
 // in the foreground.
 Log.e("MY_APP_TAG", "System killed the WebView rendering process " +
 "to reclaim memory. Recreating...");
 if (mWebView != null) {
 ViewGroup webViewContainer =
 (ViewGroup) findViewById(R.id.my_web_view_container);
 webViewContainer.removeView(mWebView);
 mWebView.destroy();
 mWebView = null;
 }
 // By this point, the instance variable "mWebView" is guaranteed
 // to be null, so it's safe to reinitialize it.
 return true; // The app continues executing.应用继续执行
 }
 // Renderer crashed because of an internal error, such as a memory
 // access violation.
 Log.e("MY_APP_TAG", "The WebView rendering process crashed!");
 // In this example, the app itself crashes after detecting that the
 // renderer crashed. If you choose to handle the crash more gracefully
 // and allow your app to continue executing, you should 1) destroy the
 // current WebView instance, 2) specify logic for how the app can
 // continue executing, and 3) return "true" instead.
 return false;
 }
}

 /***
 * 如果用户已经登录,则同步本地的cookie到webview中
 */
 public void synCookies() {
 if (!CacheUtils.isLogin(this)) return;
 CookieSyncManager.createInstance(this);
 CookieManager cookieManager = CookieManager.getInstance();
 cookieManager.setAcceptCookie(true);
 cookieManager.removeSessionCookie();//移除
 String cookies = PreferenceHelper.readString(this, AppConfig.COOKIE_KEY, AppConfig.COOKIE_KEY);
 KJLoger.debug(cookies);
 cookieManager.setCookie(url, cookies);
 CookieSyncManager.getInstance().sync();
 }

12,在页面中先显示图片:

@Override 
public void onLoadResource(WebView view, String url) { 
 mEventListener.onWebViewEvent(CustomWebView.this, OnWebViewEventListener.EVENT_ON_LOAD_RESOURCE, url); 
 if (url.indexOf(".jpg") > 0) { 
 hideProgress(); //请求图片时即显示页面 
 mEventListener.onWebViewEvent(CustomWebView.this, OnWebViewEventListener.EVENT_ON_HIDE_PROGRESS, view.getUrl()); 
 } 
 super.onLoadResource(view, url); 
} 

13,支持flash(待测)

String temp = "<html><body bgcolor=\"" + "black" 
 + "\"> <br/><embed src=\"" + url + "\" width=\"" + "100%" 
 + "\" height=\"" + "90%" + "\" scale=\"" + "noscale" 
 + "\" type=\"" + "application/x-shockwave-flash" 
 + "\"> </embed></body></html>"; 
String mimeType = "text/html"; 
String encoding = "utf-8"; 
web.loadDataWithBaseURL("null", temp, mimeType, encoding, ""); 

源码分析:
在AwContents.java中给出了什么时候才调用shouldOverrideUrlLoading (chromium46中)
源码如下:
final boolean isLoadUrl = (transitionType & PageTransition.FROM_API) != 0;
...
if ((!isLoadUrl || isRedirect) && !isBackForward && !isReload
 && !navigationParams.isPost) {
if (!mContentsClient.hasWebViewClient()) {
ignoreNavigation = AwContentsClient.sendBrowsingIntent(mContext, url,
navigationParams.hasUserGesture
 || navigationParams.hasUserGestureCarryover,
 navigationParams.isRedirect);
} else {
ignoreNavigation = mContentsClient.shouldOverrideUrlLoading(url);
}
}
 
从上面可以看出,浏览器如下行为:前进后退(isBackForward ),刷新(isReload),Post请求(navigationParams.isPost)都不会触发shouldOverrideUrlLoading.
 
如果都不是以上行为,还要满足isRedirect或!isLoadUrl 才能触发shouldOverrideUrlLoading.
isRedirect就是重定向的url,即重定向url也会触发shouldOverrideUrlLoading;这里重点介绍以下isLoadUrl.
凡是webview.loadUrl出load页面的,isLoadUrl都是true(原因是webview.loadUrl最终会调到loadUrl(LoadUrlParams params),进而params.setTransitionType(params.getTransitionType() | PageTransition.FROM_API)).