Summary
The signature capture field in the FieldPulse mobile app may become unresponsive or fail to register touch input on older devices, particularly those with degraded touch digitizers or outdated Android WebView components.
Symptoms
What I typically see in the field when this issue occurs:
- The signature field appears visually normal but does not respond to finger or stylus input
- Touch input registers elsewhere in the app, but specifically not within the signature capture canvas
- The issue may be intermittent, working in some work orders but not others
- Users report needing to tap repeatedly before any mark appears
- In severe cases, the app may freeze for several seconds when attempting to activate the signature field
Affected Devices and Platforms
In my experience, this issue is most commonly reported on:
- Android devices running Android 10 or earlier
- Devices with screen protectors that have air gaps or cracks
- Hardware with degraded touch digitizers (often field tablets used in rough environments)
- Samsung Galaxy Tab A series (2019 and earlier models)
- Zebra TC series rugged devices with older firmware
The issue is rarely seen on iOS devices, though it can occur on iPad mini 4 and earlier.
Root Cause
There are actually two distinct causes I've identified that produce very similar symptoms:
Primary Cause: WebView Rendering Pipeline
The signature capture component relies on HTML5 Canvas with touch event handling. On older Android WebView versions (prior to Chrome 90), the pointer-events CSS property and touch event coordinates can become desynchronized when the canvas is scaled for high-DPI displays. What I typically recommend is checking your WebView version first, as this is the easiest fix.
Secondary Cause: Hardware Touch Digitizer Degradation
Field devices take abuse. Over time, the capacitive touch layer can develop dead zones or reduced sensitivity in specific screen regions. The signature field is often positioned where users naturally grip the device, making it susceptible to localized wear.
Resolution
For WebView-Related Issues
- Open Settings on the Android device
- Navigate to Apps → Android System WebView (or Google Chrome on some devices)
- Tap Update from the Play Store
- Restart the FieldPulse app completely (force stop and relaunch)
- Test signature capture in a new work order
For Hardware-Related Issues
What I typically recommend is a diagnostic approach:
- Test the signature field in both portrait and landscape orientations — if it works in one orientation but not the other, this confirms hardware degradation in a specific screen region
- Try a stylus instead of finger input — capacitive styluses can sometimes register where fingers do not
- Remove any screen protector and test again
- If the device has a "Touch Sensitivity" setting (common on Samsung), increase it to maximum
Workaround for Persistent Issues
If the above steps do not resolve the issue and you need to complete work orders immediately:
- Complete the work order without the signature
- Save as draft or complete with a note indicating "signature to follow"
- Use the Attach Photo function to capture a photo of a physical signed document
- Upload this photo as documentation
Note that this workaround is imperfect — photos of signatures are not legally equivalent to captured digital signatures in all jurisdictions, and they cannot be used with the Customer Portal e-signature feature. I recommend treating this as a temporary measure while you arrange device replacement or repair.
Prevention
In my experience, organizations that implement the following practices see significantly fewer signature field issues:
- Standardize on devices no more than 3 years old for field deployment
- Update Android WebView monthly as part of device maintenance
- Use rugged cases that prevent screen flex, which accelerates digitizer degradation
- Train technicians to avoid pressing hard on the screen — the signature algorithm is pressure-independent
For more information on supported devices, see What's New in the Mobile App — Q3 Update.
