How to get real time battery level on iOS with a 1% granularity

Question

I'm using this function to get current battery level of device:

[[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
UIDevice *myDevice = [UIDevice currentDevice];

[myDevice setBatteryMonitoringEnabled:YES];
double batLeft = (float)[myDevice batteryLevel]; 
NSLog(@"%f",batLeft);

but the result has a 5% granularity. Example: when the phone battery is at 88%, it only logs a value of 0.85. batteryLevel only returns values in increments of 0.05. For example: 0.85, 0.9, 0.95 and never returns values like 0.82 or 0.83.

Is there any solution to get a percentage with a higher precision?

Refutative

For the record: I just check your code with the iPhone 6 Plus and it does show all scalar levels, like 0.49 etc – Corrincorrina

Answer 1

check out this site : Reading the battery level programmatically

but, carefully use. all of the APIs used here are undocumented on the iPhone, and will probably lead to a rejection if you submit this application to the App Store. Although battery charge status is not exactly, I'd recommend using the UIDevice battery monitoring methods.

Writhen

Thank you for your link. I've checked out it. I saw this line: "Don't forget to remove the headers and libIOKit.A.dylib from your code before shipping!", did it mean after done, I can remove libIOKit.A.dylib and remove the headers from my code to upload to Apple Store? – Refutative

Answer 2

There are at least four different ways to read the battery level, and all four ways may return different values.

Here is a chart of these values through time.

The values were recorded with this iOS project: https://github.com/nst/BatteryChart

Please check out the code for reference.

Sumptuous

Does this app remain running and reporting percentages in the background? Or do you simply leave the app running? – Tillo

Answer 3

UIDevice *myDevice = [UIDevice currentDevice];    
[myDevice setBatteryMonitoringEnabled:YES];

double batLeft = (float)[myDevice batteryLevel] * 100;
NSLog(@"%.f", batLeft);    

NSString * levelLabel = [NSString stringWithFormat:@"%.f%%", batLeft];    
lblLevel.text = levelLabel;

Hsu

Your first line is superfluous since you do exactly the same thing on the third line of code. – Bushtit

@VictorEngel I just edited it to remove the duplicate line of code. Thanks for pointing that out. – Heilungkiang

Answer 4

Swift version to get the battery level:

UIDevice.current.isBatteryMonitoringEnabled = true
let batteryLevel = UIDevice.current.batteryLevel 

batteryLevel return 0,39; 0,40 values for me.

Zorn

It is not working for me? Do I need to perform any other configuration? I am getting -1 as an answer. – Findlay

Did you write this code? UIDevice.current.isBatteryMonitoringEnabled = true If you didn't write this you will get -1. – Zorn

Yes, I wrote this line "UIDevice.current.isBatteryMonitoringEnabled = true". Also, I am new to developing iOS Apps. I am calling this code form viewDIdLoad() method under ViewController. Also, I am connected to a simulator, not an actual phone. Will that make a difference? – Findlay

Of course, the simulator will return "-1". Use this code only for real devices. – Zorn

Answer 5

The answers above are very good, but they are all in Obj-C, I have used these with other examples to do the same task on MonoTouch, so I am putting my code here in case anybody needs it:

try
{
    UIDevice.CurrentDevice.BatteryMonitoringEnabled = true;
    _Battery.Level = (int)(UIDevice.CurrentDevice.BatteryLevel * IOSBatteryLevelScalingFactor);
    _Battery.State = UIDevice.CurrentDevice.BatteryState;
}
catch (Exception e)
{
    ExceptionHandler.HandleException(e, "BatteryState.Update");
    throw new BatteryUpdateException();
}
finally
{
    UIDevice.CurrentDevice.BatteryMonitoringEnabled = false;
}

I also have a full post on my blog to give all the details in here

Eclipse

Answer 6

You can find a perfect answer here

Xcode: 11.4 Swift: 5.2

Click Here

Calling

Answer 7

If you are using swift 5.1 or greater this code will definitely work for you.

Step 1:- To get started, first enable the isBatteryMonitoringEnabled property of the current device, like this:-

UIDevice.current.isBatteryMonitoringEnabled = true

Step 2:- You can now read the current battery level

let level = UIDevice.current.batteryLevel
print(level)

Argentiferous