Android LiveData/StateFlow 列表项属性更新问题

Question

所以我正在更新我的RecylerView内容StateFlow<List>如下：

我的数据类：

data class Student(val name: String, var isSelected: Boolean)

我的视图模型逻辑：

fun updateStudentsOnSelectionChanged(targetStudent: Student) {
    val targetIndex = _students.value.indexOf(targetStudent)
    val isSelected = !targetStudent.isSelected

    _students.value[targetIndex].isSelected = isSelected        //<- doesn't work
} 

问题： UI没变，但isSelected内部_student变了，这是怎么回事？（和...一样LiveData）

Answer 1

我假设_students是一个StateFlow<List>. 更改模型isSelected的属性Student不会触发StateFlow. 解决方法是使数据类isSelected的属性Student不可变，以便在设置新状态时对其进行比较，MutableList从当前列表中创建一个，并使用属性Student的新值复制现有对象：isSelected

data class Student(val name: String, val isSelected: Boolean)

val students = _students.value.toMutableList()
students[targetIndex] = students[targetIndex].copy(isSelected = isSelected)
_students.value = students