Please update Example
Error: Cannot run with sound null safety, because the following dependencies don't support null safety:
- package:mp_chart
- package:path_drawing
- package:optimized_gesture_detector
- package:path_provider
- package:screenshot
- package:platform
- package:path_parsing
For solutions, see https://dart.dev/go/unsound-null-safety
/G:/AAAInstallation/src/flutter/.pub-cache/hosted/pub.dartlang.org/mp_chart-0.3.1/lib/mp/chart/chart.dart:51:12: Error: The method 'then' isn't defined for the class 'FutureOr
- 'InlineSpan' is from 'package:flutter/src/painting/inline_span.dart' ('/G:/AAAInstallation/src/flutter/packages/flutter/lib/src/painting/inline_span.dart'). Try correcting the name to the name of an existing getter, or defining a getter or field named 'text'. var preText = painter.text.text; ^^^^ /G:/AAAInstallation/src/flutter/.pub-cache/hosted/pub.dartlang.org/optimized_gesture_detector-0.0.6/lib/scale.dart:229:40: Error: Couldn't find constructor 'VelocityTracker'. _velocityTrackers[event.pointer] = VelocityTracker(event.kind); ^^^^^^^^^^^^^^^ /G:/AAAInstallation/src/flutter/.pub-cache/hosted/pub.dartlang.org/platform-2.2.1/lib/src/interface/local_platform.dart:45:41: Error: Member not found: 'packageRoot'. String get packageRoot => io.Platform.packageRoot; ^^^^^^^^^^^
FAILURE: Build failed with an exception.
-
Where: Script 'G:\AAAInstallation\src\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1159
-
What went wrong: Execution failed for task ':app:compileFlutterBuildDebug'.
Process 'command 'G:\AAAInstallation\src\flutter\bin\flutter.bat'' finished with non-zero exit value 1
- Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
- Get more help at https://help.gradle.org
BUILD FAILED in 1m 1s Exception: Gradle task assembleDebug failed with exit code 1
@krButani just modify optimized_gesture_detector like this.

But mp_chart and optimized_gesture_detector dont support null-safety, and there is a lot of work to do to migrate mp_chart into null-safety.
@krButani https://github.com/entronad/graphic and https://github.com/imaNNeo/fl_chart are some other packages to draw charts