WidgetsBindingObserver build failed

[Technorocker]

I was looking for a solution for this plugin as I was getting fails while trying to build out an apk. I jsut updated to newest version from 0.1.1 to 0.1.4 the verifyresource issue is indeed gone now but now I have a new issue with widgetbindings. This is the error I'm getting when build fails...

../flutter/.pub-cache/hosted/pub.dartlang.org/audio_waveforms-0.1.4/lib/src/audio_waveforms.dart:176:29: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../flutter/packages/flutter/lib/src/widgets/binding.dart').  
Try calling using ?. instead.
    WidgetsBinding.instance.addPostFrameCallback((_) {
                            ^^^^^^^^^^^^^^^^^^^^
../flutter/.pub-cache/hosted/pub.dartlang.org/audio_waveforms-0.1.4/lib/src/controllers/recorder_controller.dart:203:29: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../flutter/packages/flutter/lib/src/widgets/binding.dart').  
Try calling using ?. instead.
    WidgetsBinding.instance.addPostFrameCallback((_) {

The only 2 places I use the audiowaveform I also use a timer in the widget so I use the WidgetsBindingObserver on the class.

So after checking out the two errors a bit more I went to the 2 locations that you use addPostFrameCallback and added an ! at the end of instance like so for the first file reference...

    WidgetsBinding.instance!.addPostFrameCallback((_) {
      setState(() {});
    });

and again for the second file reference

    WidgetsBinding.instance!.addPostFrameCallback((_) {
      shouldClearLabels = false;
      notifyListeners();
    });

After I added those 2 exclamation marks I am able to build the apk now

[Ujas-Majithiya]

@Technorocker I think you are using lower version of flutter. With flutter 3.0, there was change in nullability of WidgetsBinding.instance. So, we no longer require adding ? or ! after WidgetsBinding.instance. I recommend updating your flutter sdk.

[Technorocker]

Ah ok, Ya im not upgrading past the version im using for my current app. Last time i tried that I spent an entire day trying to figure out how to downgrade my flutter/gradle/android/blah after most the plugins I'm using werent compatible unfortunately.

But good to know, thank you for response.

[Ujas-Majithiya]

@Technorocker #103 will fix the errors you were getting for postFrameCallback.