Help with Heart Rate on Watch Face

nimrag over 4 years ago

What is the best method to show the heart rate on a watch face? Can someone point me in the right direction?

I have selected the User Profile plus written the following code onto the view.mc file.

function onUpdate(dc) {

View.onUpdate(dc);

var actInfo = Act.getActivityInfo();

var devStat = System.getDeviceSettings();

var heartRate = 0;

if (ActivityMonitor has :getHeartRateHistory) {

var hrHist = ActivityMonitor.getHeartRateHistory(1, true);

heartRate = hrHist.next().heartRate;

} else {

heartRate = null;

}

0 jim_m_58 over 4 years ago

The general flow many use is this (the device needs to have OHR)

var hr=Activity.getActivityInfo().currentHeartRate; //get the latest HR if available

if(hr==null) {

//read the newest sample from history, but it sill could be null

}

Using Activity.Info will get you the "real time" heartrate, but can be null if the watch isn't being worn. It will also be null on a fenix5x.

If it is null, fall back to the history, but the history is only updated every 2 minutes or so.

When testing in the sim, use "simulation>fit data>simulate data to" supply a stream of HR values for Activity.Info

0 nimrag over 4 years ago in reply to jim_m_58

Thank you!

0 nimrag over 4 years ago in reply to jim_m_58

I see null when the sim stops. would the word null appear on the actual watch? is there a way to avoid it showing?

0 jim_m_58 over 4 years ago in reply to nimrag

If you take off the watch, yes.

if it's null, display something like "--" instead.

0 nimrag over 4 years ago in reply to jim_m_58

unfortunately, the screen still reads null when I updated with "--".

0 nimrag over 4 years ago in reply to jim_m_58

Wait, i think i misunderstood. Are you saying the actual watch would read -- on the screen but the simulator would read null if there is no HR if I keep the code with if(hr==null) ?

Also, I tried creating a boolean for the hr. Basically giving the user the capability to display or remove the hr. Is that possible?

0 FlowState over 4 years ago in reply to nimrag

He's saying that either currentHeartRate or the HR from history could be null. When a null value is converted to a string, it literally becomes "null", so you need fall back to some other value of your choice in this case, such as "--". Note that getHeartRateHistory() can also return INVALID_HR_SAMPLE (255).

So your code will look something like this:

var heartRate = Activity.getActivityInfo().currentHeartRate; //get the latest HR if available
if (heartRate == null) {
    if (ActivityMonitor has :getHeartRateHistory) {
        var hrHist =  ActivityMonitor.getHeartRateHistory(1, true);
        heartRate = hrHist.next().heartRate;
    }
}

if (heartRate == null || heartRate == 255 /* ActivityMonitor.INVALID_HR_SAMPLE */) {
    heartRate = "--"; // or whatever
}

// Display heartRate...

0 FlowState over 4 years ago in reply to nimrag

nimrag said:
Also, I tried creating a boolean for the hr. Basically giving the user the capability to display or remove the hr. Is that possible?

Yes, you can either use app settings (configured in the Garmin Connect or Connect IQ phone apps) or implement on-device settings for Connect IQ 3.2 devices.

https://developer.garmin.com/connect-iq/core-topics/app-settings/

0 nimrag over 4 years ago in reply to FlowState

Thank you. Understood that either could be null. But the display continues to show the word null on my simulator. Would it say null on the user's device or is there a way to have it reflect nothing at all? Or maybe I am writing the code incorrectly? I did use this code you provided and do see the HR and the word null when the sim is stopped.

0 nimrag over 4 years ago in reply to FlowState

Thank you. I was able to create it in settings.