使用WebView监控网页加载状况，PerformanceMonitor，WebViewClient生命周期

原理：WebView加载Url完成后，注入js脚本，脚本代码使用W3C的PerformanceTimingAPI，

往js脚本传入一个Android对象(代码中为AndroidObject)，在js脚本中调用AndroidObject中的接口，以此方式将结果传回到Android代码中。

可获取的信息：

坑（注意）：

　　1、WebViewClent的onPageFinished()方法在不同的机型下会有不同的回调情况，在所测机型中魅族Pro6只会在全部网页资源加载完成以及 webView.getProgress()==100 的情况下才会回调，且只会回调一次，华为Mate7则会在所有加载网页资源尚未加载完成( webView.getProgress()<100 )时就会回调,而且即使 webView.getProgress()==100 的情况下也会回调多次，时间难以把握，此时需自己另外加判断，只有在 webView.getProgress()==100 的情况下才执行脚本，且只能执行一次。造成此种情况的原因为WebViewClent底层JNI对不同浏览器内核的适应情况较差，WebChromeClient的onProgressChanged()方法不会出现这种情况。

　　2、注入js脚本之后需要延时一段时间才能销毁WebView，否则将收不到js返回来的结果，不能在onPageFinished()中(主线程)做耗时操作，需要另外开启一个线程去做延时关闭，然后通过消息机制将销毁WebView的msg发送给Handler处理，在主线中才能销毁WebView。

　　3、在初始化WebView时是通过 WebView mWebView = new WebView(mContext); 方式，所以在销毁WebView时出现了坑，一开始是使用如下方式进行WebView销毁，但是发现run()方法不被调用，但是hasEnqueue却返回的true，查看文档发现即使在enqueue的情况下该Runnable也并不一定会调用，最后使用 mHandler = new Handler(Lopper.getMainLooper()){...} 方法解决了问题。

 1                 boolean hasEnqueue = mWebView.postDelayed(new Runnable() {
 2                     @Override
 3                     public void run() {
 4                         //didn't step into here
 5                         if (mWebView != null) {
 6                             mWebView.clearCache(true);
 7                             mWebView.clearHistory();
 8                             mWebView.destroy();
 9                             mWebView = null;
10                         }
11                     }
12                 }, 500);
13                 if(hasEnqueue){
14                     Logger.d("the Runnable was successfully placed in to the message queue.");
15                 }else{
16                     Logger.d("the Runnable was failed to be placed in to the message queue.");
17                 }

使用mWebView.postDelayed销毁mWebView

    Handler mHandler = new Handler(Looper.getMainLooper()) {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_DESTROY: {
                    destroyWebView();
                    break;
                }
                default:
                    super.handleMessage(msg);
            }
        }
    };

使用mHandler.handleMessage()销毁mWebView

执行结果：

可通过修改注入的js脚本获取更多详细信息。

代码：

 1         final MyWebView mWebView = new MyWebView(mContext);
 2         mWebView.setVisibility(View.GONE);
 3 
 4         WebSettings setting = mWebView.getSettings();
 5         setting.setJavaScriptEnabled(true);
 6         setting.setCacheMode(WebSettings.LOAD_NO_CACHE);
 7         setting.setLoadsImagesAutomatically(false);
 8 
 9         MyWebViewClient myWebViewClient = new MyWebViewClient();
10         myWebViewClient.setTimeOut(timingCheck.getTimeout());
11         mWebView.setWebViewClient(myWebViewClient);
12 
13         mWebView.setAndroidObject(new AndroidObject() {
14             @Override
15             public void handleError(String msg) {
16                 Logger.d("AndroidObject,错误信息:" + msg);
17             }
18 
19             @Override
20             public void handleResource(String jsonStr) {
21                 Logger.d("AndroidObject,Timing信息:" + jsonStr);
22             }
23         });
24         mWebView.loadUrl("http:www.qq.com/");

Main.java

  1 import android.graphics.Bitmap;
  2 import android.net.http.SslError;
  3 import android.os.Handler;
  4 import android.os.Looper;
  5 import android.os.Message;
  6 import android.webkit.SslErrorHandler;
  7 import android.webkit.WebResourceError;
  8 import android.webkit.WebResourceRequest;
  9 import android.webkit.WebResourceResponse;
 10 import android.webkit.WebView;
 11 import android.webkit.WebViewClient;
 12 
 13 import com.gomo.health.plugin.plugin.Constants;
 14 import com.gomo.health.plugin.utils.Logger;
 15 
 16 import java.util.Timer;
 17 import java.util.TimerTask;
 18 import java.util.concurrent.atomic.AtomicBoolean;
 19 
 20 
 21 /**
 22  * Created by s_x_q on 2017/4/11.
 23  */
 24 public class MyWebViewClient extends WebViewClient {
 25 
 26     private WebView mWebView;
 27     private AndroidObject mAndroidObject;
 28 
 29     /**
 30      * WebView不支持修改Timeout , 这里自定义
 31      */
 32     private int mTimeOut = 3000;
 33     private int mJsTimeout = 500;
 34 
 35     private Timer mTimer = new Timer();
 36 
 37     /**
 38      * 避免重复执行mWebsiteLoadTimeoutTask
 39      */
 40     private boolean isWebTimeoutTaskScheduling = false;
 41 
 42     /**
 43      * 避免重复执行mJsInjectTimeoutTask
 44      */
 45     private boolean isJsTimeoutTaskScheduling = false;
 46 
 47     /**
 48      * 判断网页加载是否完成
 49      */
 50     private AtomicBoolean isWebLoadFinished = new AtomicBoolean(false);
 51 
 52     private TimerTask mWebsiteLoadTimeoutTask = new TimerTask() {
 53         @Override
 54         public void run() {
 55             if (mWebView != null && !isWebLoadFinished.get()) {
 56                 sendWebsiteLoadTimeoutMsg();
 57             }
 58         }
 59     };
 60 
 61     private TimerTask mJsInjectTimeoutTask = new TimerTask() {
 62         @Override
 63         public void run() {
 64             if (mWebView != null && mAndroidObject != null) {
 65                 if (!mAndroidObject.isDataReturn()) {
 66                     sendJsInjectTimeoutMsg();
 67                 } else {
 68                     sendDestroyMsg();
 69                 }
 70             }
 71         }
 72     };
 73 
 74     final Handler handler = new Handler(Looper.getMainLooper()) {
 75         @Override
 76         public void handleMessage(Message msg) {
 77             switch (msg.what) {
 78                 case Constants.HandlerMessage.MSG_DESTROY: {
 79                     destroyWebView();
 80                     break;
 81                 }
 82                 case Constants.HandlerMessage.MSG_WEBSITE_LOAD_TIMEOUT: {
 83                     if (mWebView != null) {
 84                         Logger.d("网页加载超时 , WebView进度:" + mWebView.getProgress() + " ,  url:" + mWebView.getUrl());
 85                         if (mWebView.getProgress() < 100) {
 86                             mAndroidObject.handleError("LoadUrlTimeout");
 87                             destroyWebView();
 88                         }
 89                     }
 90                     break;
 91                 }
 92                 case Constants.HandlerMessage.MSG_JS_INJECT_TIMEOUT: {
 93                     if (mWebView != null) {
 94                         if (mAndroidObject != null) {
 95                             if (!mAndroidObject.isDataReturn()) {
 96                                 Logger.d("JS注入脚本执行超时");
 97                                 String format = "ExecuteJsTimeout(%dms)";
 98                                 mAndroidObject.handleError(String.format(format, mJsTimeout));
 99                                 destroyWebView();
100                             }
101                         }
102                     }
103                     break;
104                 }
105 
106                 default:
107                     super.handleMessage(msg);
108             }
109         }
110     };
111 
112     @Override
113     public void onPageStarted(WebView view, String url, Bitmap favicon) {
114         super.onPageStarted(view, url, favicon);
115         Logger.d("网页开始加载:" + url);
116 
117         if (mWebView == null) {
118             mWebView = view;
119             if (mWebView instanceof MyWebView) {
120                 mAndroidObject = ((MyWebView) mWebView).getAndroidObject();
121             }
122         }
123         setupWebLoadTimeout();
124     }
125 
126     @Override
127     public boolean shouldOverrideUrlLoading(WebView view, String url) {
128         //只会重定向时回调,然后回调onPageStarted
129 //        Logger.d("回调旧版shouldOverrideUrlLoading ， url :" + url);
130         return super.shouldOverrideUrlLoading(view, url);
131     }
132 
133     @Override
134     public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
135         //只会重定向时回调,然后回调onPageStarted
136 //        Logger.d("回调新版shouldOverrideUrlLoading ， request method :" + request.getMethod() + "\t是否为重定向: " + request.isRedirect() + "\trequest url :" + request.getUrl());
137         return super.shouldOverrideUrlLoading(view, request);
138     }
139 
140     @Override
141     public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
142         //每次请求资源的时候都会在onLoadResource前回调，可用于拦截资源加载，修改request
143 //        Logger.d("回调旧版shouldInterceptRequest ， url :" + url);
144         return super.shouldInterceptRequest(view, url);
145     }
146 
147     @Override
148     public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
149         //每次请求资源的时候都会在onLoadResource前回调，可用于拦截资源加载，修改request
150 //        Logger.d("回调新版shouldInterceptRequest " );
151         return super.shouldInterceptRequest(view, request);
152     }
153 
154     @Override
155     public void onLoadResource(WebView view, String url) {
156         super.onLoadResource(view, url);
157 //        Logger.d("加载网页资源 , url:" + url + " , WebView进度:" + view.getProgress());
158     }
159 
160     public void onPageFinished(WebView view, String url) {
161         super.onPageFinished(view, url);
162 
163         Logger.d("网页加载完成,WebView进度:" + view.getProgress());
164 
165 
166         //可能会在进度<100或==100的情况下出现多次onPageFinished回调
167         if (view.getProgress() == 100 && !isWebLoadFinished.get()) {
168             Logger.d("注入js脚本");
169             //可能会回调多次
170             isWebLoadFinished.set(true);
171             String format = "javascript:%s.sendResource(JSON.stringify(window.performance.timing));";
172             String injectJs = String.format(format, MyWebView.ANDROID_OBJECT_NAME);
173             view.loadUrl(injectJs);
174 
175             setupJsInjectTimeout();
176         }
177     }
178 
179     @Deprecated
180     @Override
181     public void onReceivedError(WebView view, int errorCode,
182                                 String description, String failingUrl) {
183         super.onReceivedError(view, errorCode, description, failingUrl);
184         Logger.d("回调旧版本onReceivedError():" + "错误描述:" + description + "\t错误代码:" + errorCode + "失败的Url:" + failingUrl);
185 
186         handleError(description);
187     }
188 
189     @Override
190     public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
191         super.onReceivedError(view, request, error);
192         Logger.d("回调新版本onReceivedError:");
193     }
194 
195     @Override
196     public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
197         super.onReceivedHttpError(view, request, errorResponse);
198         Logger.d("回调onRecivedHttpError:");
199         handleError("onReceivedHttpError");
200     }
201 
202     @Override
203     public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
204         super.onReceivedSslError(view, handler, error);
205         Logger.d("回调onReceivedSslError()：" + "\terror:" + error.toString());
206         handleError("onReceivedSslError");
207     }
208 
209     private void handleError(String msg) {
210         isWebLoadFinished.set(true);
211         sendDestroyMsg();
212         if (mAndroidObject != null) {
213             mAndroidObject.handleError(msg);
214         }
215 
216     }
217 
218 
219     public int getTimeOut() {
220         return mTimeOut;
221     }
222 
223     public void setTimeOut(int timeOut) {
224         mTimeOut = timeOut;
225     }
226 
227     /**
228      * 网页加载计时
229      */
230     private void setupWebLoadTimeout() {
231         if (!isWebTimeoutTaskScheduling) {
232             isWebTimeoutTaskScheduling = true;
233             mTimer.schedule(mWebsiteLoadTimeoutTask, mTimeOut);
234         }
235     }
236 
237     /**
238      * 注入js脚本执行计时
239      * <p>
240      * 注入js之后等待一段时间，如果这段时间内js不回调AndroidObject.handleResource()，则再销毁WebView
241      * 过早销毁WebView，js不回调AndroidObject.handleResource()
242      */
243     private void setupJsInjectTimeout() {
244         if (!isJsTimeoutTaskScheduling) {
245             isJsTimeoutTaskScheduling = true;
246             if (mAndroidObject != null) {
247                 mAndroidObject.setStartTime(System.currentTimeMillis());
248             }
249             mTimer.schedule(mJsInjectTimeoutTask, mJsTimeout);
250         }
251     }
252 
253     private void sendDestroyMsg() {
254         handler.sendEmptyMessage(Constants.HandlerMessage.MSG_DESTROY);
255     }
256 
257     private void sendWebsiteLoadTimeoutMsg() {
258         handler.sendEmptyMessage(Constants.HandlerMessage.MSG_WEBSITE_LOAD_TIMEOUT);
259     }
260 
261     private void sendJsInjectTimeoutMsg() {
262         handler.sendEmptyMessage(Constants.HandlerMessage.MSG_JS_INJECT_TIMEOUT);
263     }
264 
265     private void destroyWebView() {
266         if (mWebView != null) {
267             mWebView.clearCache(true);
268             mWebView.clearHistory();
269             mWebView.destroy();
270             mWebView = null;
271             Logger.d("成功销毁WebView");
272         } else {
273             Logger.d("销毁失败，WebView为空");
274         }
275     }
276 
277 }

MyWebViewClient.java

 1 import android.webkit.JavascriptInterface;
 2 
 3 
 4 /**
 5  * Created by s_x_q on 2017/4/11.
 6  */
 7 
 8 public abstract class AndroidObject {
 9 
10 
11     private volatile boolean mIsDataReturn = false ;
12     private long startTime ;
13     private long endTime ;
14 
15     /**
16      *用于收集Timing信息
17      *
18      * @param jsonStr
19      */
20     @JavascriptInterface
21     public void sendResource(String jsonStr) {
22         mIsDataReturn = true ;
23         endTime = System.currentTimeMillis();
24         Logger.d("js成功执行时间：" + (endTime-startTime));
25         handleResource(jsonStr);
26     }
27 
28 
29     /**
30      * 用于收集js的执行错误
31      * @param msg
32      */
33     @JavascriptInterface
34     public void sendError(String msg) {
35         handleError(msg);
36     }
37 
38 
39     /**
40      * 处理错误信息，可能会被回调多次
41      * @param msg
42      */
43     public abstract void handleError(String msg) ;
44 
45     /**
46      *
47      * @param jsonStr
48      */
49     public abstract void handleResource(String jsonStr);
50 
51     public boolean isDataReturn() {
52         return mIsDataReturn;
53     }
54 
55     public long getStartTime() {
56         return startTime;
57     }
58 
59     public void setStartTime(long startTime) {
60         this.startTime = startTime;
61     }
62 
63     public long getEndTime() {
64         return endTime;
65     }
66 
67     public void setEndTime(long endTime) {
68         this.endTime = endTime;
69     }
70 }

AndroidObject.java

package com.sxq.webviewperformancemonitor;

import android.content.Context;
import android.util.AttributeSet;
import android.webkit.WebView;

/**
 * Created by shixiaoqiangsx on 2017/4/11.
 */
public class MyWebView extends WebView {

    public final static String ANDROID_OBJECT_NAME = "android";

    private AndroidObject mAndroidObject = null;

    public MyWebView(Context context) {
        this(context, null, 0);
    }

    public MyWebView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyWebView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void setAndroidObject(AndroidObject object) {
        if (object == null) {
            Logger.d("AndroidObject can not be null !");
            this.mAndroidObject = new AndroidObject() {
                @Override
                public void handleError(String msg) {
                }

                @Override
                public void handleResource(String jsonStr) {
                }
            };
        } else {
            this.mAndroidObject = object;
        }

        super.addJavascriptInterface(mAndroidObject, ANDROID_OBJECT_NAME);
    }

    protected AndroidObject getAndroidObject() {
        return this.mAndroidObject;
    }
}