Home | History | Annotate | Download | only in browser 
      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.android.browser;
     17 
     18 import android.os.Looper;
     19 import android.util.Log;
     20 import android.webkit.WebView;
     21 
     22 /**
     23  * Centralised point for controlling WebView timers pausing and resuming.
     24  *
     25  * All methods on this class should only be called from the UI thread.
     26  */
     27 public class WebViewTimersControl {
     28 
     29     private static final boolean LOGD_ENABLED = com.android.browser.Browser.LOGD_ENABLED;
     30     private static final String LOGTAG = "WebViewTimersControl";
     31 
     32     private static WebViewTimersControl sInstance;
     33 
     34     private boolean mBrowserActive;
     35     private boolean mPrerenderActive;
     36 
     37     /**
     38      * Get the static instance. Must be called from UI thread.
     39      */
     40     public static WebViewTimersControl getInstance() {
     41         if (Looper.myLooper() != Looper.getMainLooper()) {
     42             throw new IllegalStateException("WebViewTimersControl.get() called on wrong thread");
     43         }
     44         if (sInstance == null) {
     45             sInstance = new WebViewTimersControl();
     46         }
     47         return sInstance;
     48     }
     49 
     50     private WebViewTimersControl() {
     51     }
     52 
     53     private void resumeTimers(WebView wv) {
     54         if (LOGD_ENABLED) Log.d(LOGTAG, "Resuming webview timers, view=" + wv);
     55         if (wv != null) {
     56             wv.resumeTimers();
     57         }
     58     }
     59 
     60     private void maybePauseTimers(WebView wv) {
     61         if (!mBrowserActive && !mPrerenderActive && wv != null) {
     62             if (LOGD_ENABLED) Log.d(LOGTAG, "Pausing webview timers, view=" + wv);
     63             wv.pauseTimers();
     64         }
     65     }
     66 
     67     public void onBrowserActivityResume(WebView wv) {
     68         if (LOGD_ENABLED) Log.d(LOGTAG, "onBrowserActivityResume");
     69         mBrowserActive = true;
     70         resumeTimers(wv);
     71     }
     72 
     73     public void onBrowserActivityPause(WebView wv) {
     74         if (LOGD_ENABLED) Log.d(LOGTAG, "onBrowserActivityPause");
     75         mBrowserActive = false;
     76         maybePauseTimers(wv);
     77     }
     78 
     79     public void onPrerenderStart(WebView wv) {
     80         if (LOGD_ENABLED) Log.d(LOGTAG, "onPrerenderStart");
     81         mPrerenderActive = true;
     82         resumeTimers(wv);
     83     }
     84 
     85     public void onPrerenderDone(WebView wv) {
     86         if (LOGD_ENABLED) Log.d(LOGTAG, "onPrerenderDone");
     87         mPrerenderActive = false;
     88         maybePauseTimers(wv);
     89     }
     90 
     91 }
     92