ios - 电池监控不定期更新

Question

我正在监视电池事件UIDeviceBatteryLevelDidChangeNotification和UIDeviceBatteryStateDidChangeNotification. 我专门寻找20%和10%，但是，我看到这些事件以 23% 和 13% 触发，它们应该以0.05间隔或每5%触发。

问题

有没有其他人遇到过这种情况，或者有没有更好的方法来确保水平更准确？

例子

-(void)startMonitoringForBatteryChanges
{
    // Enable monitoring of battery status
    [[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];

    // Request to be notified when battery charge or state changes
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkBatteryStatus) name:UIDeviceBatteryLevelDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkBatteryStatus) name:UIDeviceBatteryStateDidChangeNotification object:nil];
}

- (void)checkBatteryStatus
{
    float warningLevel = [[UIDevice currentDevice] batteryLevel] * 100;

    if ( warningLevel == 20.0 ) // 20%
    {
        NSLog(@"20% Warning.");
    }

    if ( warningLevel == 10.0 ) // 10%
    {
        NSLog(@"10% Warning.");
    }
}