通过选择 flutter 中的值未更新下拉按钮

Question

Whenever I try to update the value into the desired one it doesn't change

Here's a snippet of the relevant code:

new DropdownButton<String>(
            items: <String>['A', 'B', 'C', 'D'].map((String value) {
              return new DropdownMenuItem<String>(
                value: value,
                child: new Text(value),
              );
            }).toList(),
              onChanged: (value) {
                setState(() {
                  value1 = value!;
                });
              }
          )

Answer 1

Looks like the issue is that the name of the variable you're updating in setState is named value1, while the variable you assign to the value parameter in your DropdownMenuItem is named value.

Try using the following code for onChanged:

onChanged: (newValue) {
            setState(() {
              value = newValue;
            });
          }