Null check operator used on a null value, this error generally occurs in Flutter for developers. So in this tutorial we will strongly learn about this and also for the solution for it. Keep continue to looking.
In Dart, the null check operator ! is used to assert that a value isn’t null. It is useful when ussing with nullable type values allowing you to access properties or call methods without explicitly handling null checks.
String? nullableString; // Nullable String
void main() {
// Assume nullableString is null
print(nullableString!.toUpperCase()); // Using null check operator
// Output: Unhandled exception: Null check operator used on a null value
}
In this example, nullableString is declared as nullable (String?). When we try to call the toUpperCase() method on nullableString using !, we’re asserting that nullableString isn’t null. If nullableString is indeed null at runtime, Dart will throw a runtime exception.
To safely handle nullable values, you can use conditional checks or the null-aware operators (?., ??, ??=). For instance:
Handling Null Values
String? nullableString; // Nullable String
void main() {
if (nullableString != null) {
print(nullableString!.toUpperCase());
} else {
print('nullableString is null');
}
}
In this modified example, we explicitly check if nullableString is not null before calling toUpperCase(). This ensures that the code won’t throw a runtime exception if nullableString is null.
In Dart language ” ? ” operator is is used to check null values. Flutter also provide null safety feature to check null value or not.
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