src/ios/CDVBattery.m

/*
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you under the Apache License, Version 2.0 (the
 "License"); you may not use this file except in compliance
 with the License.  You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing,
 software distributed under the License is distributed on an
 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 KIND, either express or implied.  See the License for the
 specific language governing permissions and limitations
 under the License.
 */

#import "CDVBattery.h"

@interface CDVBattery (PrivateMethods)
- (void)updateOnlineStatus;
@end

@implementation CDVBattery

@synthesize state, level, callbackId, isPlugged;

/*  determining type of event occurs on JavaScript side
- (void) updateBatteryLevel:(NSNotification*)notification
{
    // send batterylow event for less than 25% battery
    // send batterycritical  event for less than 10% battery
    // W3c says to send batteryStatus event when batterylevel changes by more than 1% (iOS seems to notify each 5%)
    // always update the navigator.device.battery info
    float currentLevel = [[UIDevice currentDevice] batteryLevel];
    NSString* type = @"";
    // no check for level == -1 since this api is only called when monitoring is enabled so level should be valid
    if (currentLevel < 0.10){
        type = @"batterycritical";
    } else if (currentLevel < 0.25) {
        type = @"batterylow";
    } else {
        float onePercent = 0.1;
        if (self.level >= 0 ){
            onePercent = self.level * 0.01;
        }
        if (fabsf(currentLevel - self.level) > onePercent){
            // issue batteryStatus event
            type = @"batterystatus";
        }
    }
    // update the battery info and fire event
    NSString* jsString = [NSString stringWithFormat:@"navigator.device.battery._status(\"%@\", %@)", type,[[self getBatteryStatus] JSONRepresentation]];
    [super writeJavascript:jsString];
}
 */

- (void)updateBatteryStatus:(NSNotification*)notification
{
    NSDictionary* batteryData = [self getBatteryStatus];

    if (self.callbackId) {
        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDictionary:batteryData];
        [result setKeepCallbackAsBool:YES];
        [self.commandDelegate sendPluginResult:result callbackId:self.callbackId];
    }
}

/* Get the current battery status and level.  Status will be unknown and level will be -1.0 if
 * monitoring is turned off.
 */
- (NSDictionary*)getBatteryStatus
{
    UIDevice* currentDevice = [UIDevice currentDevice];
    UIDeviceBatteryState currentState = [currentDevice batteryState];

    isPlugged = FALSE; // UIDeviceBatteryStateUnknown or UIDeviceBatteryStateUnplugged
    if ((currentState == UIDeviceBatteryStateCharging) || (currentState == UIDeviceBatteryStateFull)) {
        isPlugged = TRUE;
    }
    float currentLevel = [currentDevice batteryLevel];

    if ((currentLevel != self.level) || (currentState != self.state)) {
        self.level = currentLevel;
        self.state = currentState;
    }

    // W3C spec says level must be null if it is unknown
    NSObject* w3cLevel = nil;
    if ((currentState == UIDeviceBatteryStateUnknown) || (currentLevel == -1.0)) {
        w3cLevel = [NSNull null];
    } else {
        w3cLevel = [NSNumber numberWithFloat:(currentLevel * 100)];
    }
    NSMutableDictionary* batteryData = [NSMutableDictionary dictionaryWithCapacity:2];
    [batteryData setObject:[NSNumber numberWithBool:isPlugged] forKey:@"isPlugged"];
    [batteryData setObject:w3cLevel forKey:@"level"];
    return batteryData;
}

/* turn on battery monitoring*/
- (void)start:(CDVInvokedUrlCommand*)command
{
    self.callbackId = command.callbackId;

    if ([UIDevice currentDevice].batteryMonitoringEnabled == NO) {
        [[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateBatteryStatus:)
                                                     name:UIDeviceBatteryStateDidChangeNotification object:nil];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateBatteryStatus:)
                                                     name:UIDeviceBatteryLevelDidChangeNotification object:nil];
    }
}

/* turn off battery monitoring */
- (void)stop:(CDVInvokedUrlCommand*)command
{
    // callback one last time to clear the callback function on JS side
    if (self.callbackId) {
        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDictionary:[self getBatteryStatus]];
        [result setKeepCallbackAsBool:NO];
        [self.commandDelegate sendPluginResult:result callbackId:self.callbackId];
    }
    self.callbackId = nil;
    [[UIDevice currentDevice] setBatteryMonitoringEnabled:NO];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceBatteryStateDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceBatteryLevelDidChangeNotification object:nil];
}

- (void)pluginInitialize
{
    self.state = UIDeviceBatteryStateUnknown;
    self.level = -1.0;
}

- (void)dealloc
{
    [self stop:nil];
}

- (void)onReset
{
    [self stop:nil];
}

@end