Add Unit Support for Health Data Types & Handle Rate Limiting

[connor-callaghan]

Add Unit Support for Health Data Types

Changes

This PR adds further unit conversion support to the Health's Android implementation, specifically for Health Connect. Key improvements:

Stops crashes discussed in #1028 (underlying issue should be fixed in another pr)

Android (Kotlin)

• Added support for multiple unit types when reading and writing health data
• Implemented unit conversion functions for common health measurements:
  • Weight/Mass: kg, g, lb, oz, stone
  • Length: m, cm, in, ft
  • Temperature: °C, °F, K
  • Blood glucose: mmol/L, mg/dL
  • Volume: L, mL

Dart API Enhancements

• Added support for specifying preferred units when retrieving health data
• Added optional clientRecordId and clientRecordVersion parameters for better data tracking
• Updated HealthDataPoint factory to properly handle unit conversions
• Added CENTIMETER and MILLIMOLES_PER_LITER to HealthDataUnit enum

Benefits

• More flexibility for app developers to work with units preferred by their users
• Better support for international apps (metric vs imperial units)
• Improved consistency with iOS implementation
• Maintains backward compatibility with existing code

This implementation preserves all existing functionality while extending the plugin's capabilities to handle different measurement units consistently.

[iarata]

Thank you for the PR,

Why the following check was removed from getHealthConnectSdkStatus

if (healthConnectAvailable) {
    healthConnectClient =
         HealthConnectClient.getOrCreate(
             context!!
         )
}

Also, when running the example app it returns with the following error:

E/MethodChannel#flutter_health( 5630): Failed to handle method call
E/MethodChannel#flutter_health( 5630): java.lang.NullPointerException
E/MethodChannel#flutter_health( 5630):  at cachet.plugins.health.HealthPlugin.writeData(HealthPlugin.kt:1771)
E/MethodChannel#flutter_health( 5630):  at cachet.plugins.health.HealthPlugin.onMethodCall(HealthPlugin.kt:165)
E/MethodChannel#flutter_health( 5630):  at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:267)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:292)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/MethodChannel#flutter_health( 5630):  at android.os.Handler.handleCallback(Handler.java:995)
E/MethodChannel#flutter_health( 5630):  at android.os.Handler.dispatchMessage(Handler.java:103)
E/MethodChannel#flutter_health( 5630):  at android.os.Looper.loopOnce(Looper.java:248)
E/MethodChannel#flutter_health( 5630):  at android.os.Looper.loop(Looper.java:338)
E/MethodChannel#flutter_health( 5630):  at android.app.ActivityThread.main(ActivityThread.java:9067)
E/MethodChannel#flutter_health( 5630):  at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#flutter_health( 5630):  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
E/MethodChannel#flutter_health( 5630):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:932)
E/flutter ( 5630): [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: PlatformException(error, null, null, java.lang.NullPointerException
E/flutter ( 5630):      at cachet.plugins.health.HealthPlugin.writeData(HealthPlugin.kt:1771)
E/flutter ( 5630):      at cachet.plugins.health.HealthPlugin.onMethodCall(HealthPlugin.kt:165)
E/flutter ( 5630):      at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:267)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:292)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/flutter ( 5630):      at android.os.Handler.handleCallback(Handler.java:995)
E/flutter ( 5630):      at android.os.Handler.dispatchMessage(Handler.java:103)
E/flutter ( 5630):      at android.os.Looper.loopOnce(Looper.java:248)
E/flutter ( 5630):      at android.os.Looper.loop(Looper.java:338)
E/flutter ( 5630):      at android.app.ActivityThread.main(ActivityThread.java:9067)
E/flutter ( 5630):      at java.lang.reflect.Method.invoke(Native Method)
E/flutter ( 5630):      at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
E/flutter ( 5630):      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:932)
E/flutter ( 5630): )
E/flutter ( 5630): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:652:7)
E/flutter ( 5630): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:370:18)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): #2      Health.writeHealthData (package:health/src/health_plugin.dart:545:21)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): #3      HealthAppState.addData (package:health_example/main.dart:214:16)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): 

[iarata]

We are testing the refactored Android version for Health (See PR #1211 - Branch health13/refactor-kotlin). Could you modify your code to match the refactored version?

[connor-callaghan]

Thank you for the PR,

Why the following check was removed from getHealthConnectSdkStatus

if (healthConnectAvailable) {
    healthConnectClient =
         HealthConnectClient.getOrCreate(
             context!!
         )
}

Also, when running the example app it returns with the following error:

E/MethodChannel#flutter_health( 5630): Failed to handle method call
E/MethodChannel#flutter_health( 5630): java.lang.NullPointerException
E/MethodChannel#flutter_health( 5630):  at cachet.plugins.health.HealthPlugin.writeData(HealthPlugin.kt:1771)
E/MethodChannel#flutter_health( 5630):  at cachet.plugins.health.HealthPlugin.onMethodCall(HealthPlugin.kt:165)
E/MethodChannel#flutter_health( 5630):  at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:267)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:292)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
E/MethodChannel#flutter_health( 5630):  at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/MethodChannel#flutter_health( 5630):  at android.os.Handler.handleCallback(Handler.java:995)
E/MethodChannel#flutter_health( 5630):  at android.os.Handler.dispatchMessage(Handler.java:103)
E/MethodChannel#flutter_health( 5630):  at android.os.Looper.loopOnce(Looper.java:248)
E/MethodChannel#flutter_health( 5630):  at android.os.Looper.loop(Looper.java:338)
E/MethodChannel#flutter_health( 5630):  at android.app.ActivityThread.main(ActivityThread.java:9067)
E/MethodChannel#flutter_health( 5630):  at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#flutter_health( 5630):  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
E/MethodChannel#flutter_health( 5630):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:932)
E/flutter ( 5630): [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: PlatformException(error, null, null, java.lang.NullPointerException
E/flutter ( 5630):      at cachet.plugins.health.HealthPlugin.writeData(HealthPlugin.kt:1771)
E/flutter ( 5630):      at cachet.plugins.health.HealthPlugin.onMethodCall(HealthPlugin.kt:165)
E/flutter ( 5630):      at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:267)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:292)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
E/flutter ( 5630):      at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/flutter ( 5630):      at android.os.Handler.handleCallback(Handler.java:995)
E/flutter ( 5630):      at android.os.Handler.dispatchMessage(Handler.java:103)
E/flutter ( 5630):      at android.os.Looper.loopOnce(Looper.java:248)
E/flutter ( 5630):      at android.os.Looper.loop(Looper.java:338)
E/flutter ( 5630):      at android.app.ActivityThread.main(ActivityThread.java:9067)
E/flutter ( 5630):      at java.lang.reflect.Method.invoke(Native Method)
E/flutter ( 5630):      at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
E/flutter ( 5630):      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:932)
E/flutter ( 5630): )
E/flutter ( 5630): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:652:7)
E/flutter ( 5630): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:370:18)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): #2      Health.writeHealthData (package:health/src/health_plugin.dart:545:21)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): #3      HealthAppState.addData (package:health_example/main.dart:214:16)
E/flutter ( 5630): <asynchronous suspension>
E/flutter ( 5630): 

@iarata Thanks for looking at this, the check removal was a mistake. I will update this pr, adding back the check, a fix for the logs, and a sync with #1211 shortly.