The error from the title is returned for the following code, which makes no sense
private val _error = MutableLiveData<String?>()
val error: LiveData<String?> get() = _error
_error.postValue(null) //Error Cannot set non-nullable LiveData value to null [NullSafeMutableLiveData]
parameter String of _error is obviously nullable, am I doing something wrong?
This has been fixed in version 2.3.1.
https://developer.android.com/jetpack/androidx/releases/lifecycle#version_231_2
This appears to be related to a bug already reported against androidx.lifecycle pre-release of 2.3.0 https://issuetracker.google.com/issues/169249668.
Workarounds I have found:
NullSafeMutableLiveData inbuild.gradle
android {
...
lintOptions {
disable 'NullSafeMutableLiveData'
}
}
or lint.xml in root dir
<?xml version="1.0" encoding="UTF-8"?>
<lint>
<issue id="NullSafeMutableLiveData" severity="warning" />
</lint>
MutableLiveData encapsulation via backing properties dance (which really hurts my eyes).class ExampleViewModel : ViewModel() {
private val _data1 = MutableLiveData<Int>()
val data1: LiveData<Int> = _data1
private val _data2 = MutableLiveData<Int?>()
val data2: LiveData<Int?> = _data2
fun funct() {
_data1.value = 1
_data2.value = null
}
}
It seems fixed in lifecycle 2.4.0-SNAPSHOT. Please wait for the official release.
This issue was coming in 2.3.0 also but after upgrading to 2.4.0 it is not coming.