flutter - 如何在 labelText 悬停到 textField 的左上角后为其添加颜色？

Question

我想在 labelText 悬停在 TextField 的左上角后为其赋予不同的颜色。

 TextField(
              focusNode: mailFocusNode,
              onTap: () {
                FocusScope.of(context).requestFocus(mailFocusNode);
              },
              decoration: InputDecoration(
                labelText: "E-mail",
                labelStyle: TextStyle(color: Colors.purple),
                enabledBorder: OutlineInputBorder(
                   borderSide: BorderSide(color: Colors.white),
                    borderRadius: BorderRadius.circular(25.0),
                 ),
                focusedBorder: OutlineInputBorder(
                    borderSide: BorderSide(color: Colors.white),
                    borderRadius: BorderRadius.circular(25.0),
                  ),
                ),
              keyboardType: TextInputType.emailAddress,
              controller: _controllerEmail,
              onChanged: (String value) {
                  setState(() {
                    _email = value;
                  });
                },
              ),

我希望 LabelText 在 TextField 上和悬停时有不同的颜色

Answer 1

如果我没看错，你想在 TextField 获得焦点时更改标签的颜色，这意味着当 labelText 移动到左上角时。

TextField(
  focusNode: mailFocusNode,
  onTap: () {
    _color = Colors.blue; // set your new Color
    FocusScope.of(context).requestFocus(mailFocusNode);
    setState(() {});
  },
  decoration: InputDecoration(
    labelText: "E-mail",
    labelStyle: TextStyle(color: _color),
    enabledBorder: OutlineInputBorder(
      borderSide: BorderSide(color: Colors.white),
      borderRadius: BorderRadius.circular(25.0),
    ),
    focusedBorder: OutlineInputBorder(
      borderSide: BorderSide(color: Colors.white),
      borderRadius: BorderRadius.circular(25.0),
    ),
  ),
  keyboardType: TextInputType.emailAddress,
  controller: _controllerEmail,
  onChanged: (String value) {
    setState(() {
      _email = value;
    });
  },
)