Flutter：如何制作随机颜色生成器背景 [英] Flutter: How can I make a Random color generator Background

问题描述

生成随机颜色

Generate random colors

return new RaisedButton(


    padding:  EdgeInsets.symmetric(vertical: 30.0),
    color: Colors.primaries random  List <blue,green>,

推荐答案

您可以使用 Random 类进行操作：

You can use Random class to do that:

但是，如果要在按下按钮时更改颜色，则必须使用 StatefulWidget 。简单的例子如下：

But if you want to change the color when button is pressed, you have to use a StatefulWidget. A simple example is like below:

import 'package:flutter/material.dart';
import 'dart:math';

void main() {
  runApp(
    MaterialApp(
      home: MyApp(),
    ),
  );
}

class MyApp extends StatefulWidget {
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {

  List colors = [Colors.red, Colors.green, Colors.yellow];
  Random random = new Random();

  int index = 0;

  void changeIndex() {
    setState(() => index = random.nextInt(3));
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: RaisedButton(
        onPressed: () => changeIndex(),
        child: Text('Click'),
        color: colors[index],
      ),
    );
  }
}

此外，还有一个名为 random_pk 由 pawankumar ，每次调用您应用的构建方法时，都会为我们提供随机颜色。

Also, there is a package called random_pk by pawankumar, that will give us random color each and every time your app's build method get called.

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