Question

我是新手，我需要知道一件事，我正在函数中计算一些值，需要在文本小部件中显示此值，这怎么可能？

这是我的功能

  final List _questions = [
    {'would': 'Coffe1', 'rather': 'Tea', 'wouldclick': '1', 'ratherclick':'2'},
    {'would': 'Blue', 'rather': 'Red', 'wouldclick': '2', 'ratherclick':'2'},
    {'would': 'Green', 'rather': 'Yellow', 'wouldclick': '3', 'ratherclick':'2'},
  ];

  int index = 0;
  void percentage1Calculate(){
     final percentage1 = _questions[index]['wouldclick'] / _questions[index]['wouldclick'] + _questions[index]['ratherclick'] * 100;
  }
  void percentage2Calculate(){
     final percentage2 = _questions[index]['ratherclick'] / _questions[index]['wouldclick'] + _questions[index]['ratherclick'] * 100;
  }

并且需要在列中显示

Column(
     children: <Widget>[
       Text(percentage1),
       Text(percentage2),
    ]
)

Answer 1

您的数字看起来实际上是String类型，请在进行数学运算之前先进行转换：

double percentage1Calculate(){
     int wouldClick = int.parse(_questions[index]['wouldclick']);
     int ratherClick = int.parse(_questions[index]['ratherclick']);
     double percentage1 = wouldClick / wouldClick + ratherClick * 100;
     return percentage1;
}

然后，您应该可以像这样设置变量：

Text('${percentage1Calculate()}');

如果将其设为get方法，则可以这样使用它：

double get percentage1Calculate {
     int wouldClick = int.parse(_questions[index]['wouldclick']);
     int ratherClick = int.parse(_questions[index]['ratherclick']);
     double percentage1 = wouldClick / wouldClick + ratherClick * 100;
     return percentage1;
}

Text('$percentage1Calculate');

Answer 2

您可以返回在函数中计算出的值，并将其作为值传递到小部件内。

假设您的函数返回int，

int percentage1Calculate(){
  final percentage1 = _questions[index]['wouldclick'] / _questions[index] ['wouldclick'] + _questions[index]['ratherclick'] * 100;
  return percentage1;
}

调用上述函数并将其保存在变量中，

int store = percentage1Calculate();

在小部件中使用它，如下所示，

Text(data: $store);

在颤振中如何从函数中获取值？

2 个答案: