PowerMonitor.java revision a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7 
1// Copyright 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5package org.chromium.base;
6
7import android.content.Context;
8import android.content.Intent;
9import android.content.IntentFilter;
10import android.os.BatteryManager;
11import android.os.Handler;
12import android.os.Looper;
13
14
15/**
16 * Integrates native PowerMonitor with the java side.
17 */
18@JNINamespace("base::android")
19public class PowerMonitor implements ActivityStatus.StateListener {
20    private static final long SUSPEND_DELAY_MS = 1 * 60 * 1000;  // 1 minute.
21    private static class LazyHolder {
22        private static final PowerMonitor INSTANCE = new PowerMonitor();
23    }
24    private static PowerMonitor sInstance;
25
26    private boolean mIsBatteryPower;
27    private final Handler mHandler = new Handler(Looper.getMainLooper());
28
29    // Asynchronous task used to fire the "paused" event to the native side 1 minute after the main
30    // activity transitioned to the "paused" state. This event is not sent immediately because it
31    // would be too aggressive. An Android activity can be in the "paused" state quite often. This
32    // can happen when a dialog window shows up for instance.
33    private static final Runnable sSuspendTask = new Runnable() {
34            @Override
35            public void run() {
36                nativeOnMainActivitySuspended();
37            }
38        };
39
40    public static void createForTests(Context context) {
41        // Applications will create this once the JNI side has been fully wired up both sides. For
42        // tests, we just need native -> java, that is, we don't need to notify java -> native on
43        // creation.
44        sInstance = LazyHolder.INSTANCE;
45    }
46
47    public static void create(Context context) {
48        if (sInstance == null) {
49            sInstance = LazyHolder.INSTANCE;
50            ActivityStatus.registerStateListener(sInstance);
51            IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
52            Intent batteryStatusIntent = context.registerReceiver(null, ifilter);
53            onBatteryChargingChanged(batteryStatusIntent);
54        }
55    }
56
57    private PowerMonitor() {
58    }
59
60    public static void onBatteryChargingChanged(Intent intent) {
61        if (sInstance == null) {
62            // We may be called by the framework intent-filter before being fully initialized. This
63            // is not a problem, since our constructor will check for the state later on.
64            return;
65        }
66        int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
67        // If we're not plugged, assume we're running on battery power.
68        sInstance.mIsBatteryPower = chargePlug != BatteryManager.BATTERY_PLUGGED_USB &&
69                                    chargePlug != BatteryManager.BATTERY_PLUGGED_AC;
70        nativeOnBatteryChargingChanged();
71    }
72
73    @Override
74    public void onActivityStateChange(int newState) {
75        if (newState == ActivityStatus.RESUMED) {
76            // Remove the callback from the message loop in case it hasn't been executed yet.
77            mHandler.removeCallbacks(sSuspendTask);
78            nativeOnMainActivityResumed();
79        } else if (newState == ActivityStatus.PAUSED) {
80            mHandler.postDelayed(sSuspendTask, SUSPEND_DELAY_MS);
81        }
82    }
83
84    @CalledByNative
85    private static boolean isBatteryPower() {
86        return sInstance.mIsBatteryPower;
87    }
88
89    private static native void nativeOnBatteryChargingChanged();
90    private static native void nativeOnMainActivitySuspended();
91    private static native void nativeOnMainActivityResumed();
92}
93