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 */
16package com.android.browser;
17
18import android.os.Looper;
19import android.util.Log;
20import 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 */
27public 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