改变 Flutter 的 FlatButton onPressed 的颜色

Question

我想在单击按钮时更改按钮的颜色和文本。但它没有改变。我在 setState 中更改我的变量，并使用三元运算符设置文本和颜色。希望对大家有所帮助。

Container(
     padding: EdgeInsets.symmetric(horizontal: 15,vertical: 15),
     alignment: Alignment.bottomCenter,
     child: SizedBox(
            width: double.infinity, //Full width
            height: 40,
            child: FlatButton(
                child: Text( stopSelling ? "Dejar de vender" : "Empezar a vender",style: TextStyle(fontSize: 20,fontWeight: FontWeight.w300),),
                onPressed: () {
                    setState(() {
                      stopSelling = !stopSelling;
                    });
                  },
                textColor: Colors.white,
                color: stopSelling?Colors.red:Colors.green,
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
            )
     ),
   ),

Answer 1

你的代码是完美的，但我不知道你在哪里声明你的 stopSelling 变量，但我很确定你已经在 build() 方法内声明了 stopSelling 所以你必须在 build() 之外声明 stopSelling 变量class（有状态或无状态）的方法和内部。

Flutter 的生命周期规则是，当 setState() 被调用时，build() 方法会自动调用，它会像以前一样影响你的变量。

Answer 2

试试这个....

Container(
      padding: EdgeInsets.symmetric(horizontal: 15,vertical: 15),
      alignment: Alignment.bottomCenter,
      child: SizedBox(
          width: double.infinity, //Full width
          height: 40,
          child: stopSelling? FlatButton(
            child: Text( stopSelling ? "Dejar de vender" : "Empezar a vender",style: TextStyle(fontSize: 20,fontWeight: FontWeight.w300),),
            onPressed: () {
              setState(() {
                stopSelling = !stopSelling;
              });
            },
            textColor: Colors.white,
            color:  Colors.red,
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
          ):FlatButton(
            child: Text( stopSelling ? "Dejar de vender" : "Empezar a vender",style: TextStyle(fontSize: 20,fontWeight: FontWeight.w300),),
            onPressed: () {
              setState(() {
                stopSelling = !stopSelling;
              });
            },
            textColor: Colors.white,
            color: Colors.green,
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
          ),
      ),
    )

改变 Flutter 的 FlatButton onPressed 的颜色

change color of the Flutter's FlatButton onPressed

flutter

colors

widget

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