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      */
getInstance()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 
WebViewTimersControl()50     private WebViewTimersControl() {
51     }
52 
resumeTimers(WebView wv)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 
maybePauseTimers(WebView wv)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 
onBrowserActivityResume(WebView wv)67     public void onBrowserActivityResume(WebView wv) {
68         if (LOGD_ENABLED) Log.d(LOGTAG, "onBrowserActivityResume");
69         mBrowserActive = true;
70         resumeTimers(wv);
71     }
72 
onBrowserActivityPause(WebView wv)73     public void onBrowserActivityPause(WebView wv) {
74         if (LOGD_ENABLED) Log.d(LOGTAG, "onBrowserActivityPause");
75         mBrowserActive = false;
76         maybePauseTimers(wv);
77     }
78 
onPrerenderStart(WebView wv)79     public void onPrerenderStart(WebView wv) {
80         if (LOGD_ENABLED) Log.d(LOGTAG, "onPrerenderStart");
81         mPrerenderActive = true;
82         resumeTimers(wv);
83     }
84 
onPrerenderDone(WebView wv)85     public void onPrerenderDone(WebView wv) {
86         if (LOGD_ENABLED) Log.d(LOGTAG, "onPrerenderDone");
87         mPrerenderActive = false;
88         maybePauseTimers(wv);
89     }
90 
91 }
92