目前架構變成這樣

1. product_control.dart的按鈕點擊事件變成這樣，傳入一個Map物件

onPressed: () {
    addProduct({'title': 'Chocolate', 'image': 'assets/food.jpg'});
},

2. product_manager.dart的初始化傳入物件就要是個包著map物件的list(key跟value都是string)

  final Map<String, String> startingProduct;

3.State組件中的變數的資料格式也要改

List<Map<String, String>> _products = [];

4. addProduct方法的傳入值格式也要改

  void _addProduct(Map<String, String> product) {
    setState(() {
      _products.add(product);
    });
  }

5. products.dart的傳入參數是根據product_manager.dart的，所以也跟著改

final List<Map<String, String>> products;

6.flatbutton的點擊事件就可以把map物件傳進去了(索引方式真的蠻像js)

FlatButton(
    child: Text('Details'),
    onPressed: () => Navigator.push(
            context,
            MaterialPageRoute(
                builder: (BuildContext context) => ProductPage(
                    products[index]['title'], products[index]['image']
                ),
            ),
        ),
)

7. page/product.dart

import 'package:flutter/material.dart';

class ProductPage extends StatelessWidget {
  final String title;
  final String imageUrl;

  ProductPage(this.title, this.imageUrl);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.center,
        //水平置中用
        children: <Widget>[
          Image.asset(imageUrl),
          Container(
            padding: EdgeInsets.all(10.0),
            child: Text(title),
          ),
          Container(
            padding: EdgeInsets.all(10.0),
            child: RaisedButton(
              color: Theme.of(context).accentColor,
              child: Text('BACK'),
              onPressed: () => Navigator.pop(context),
            ),
          )
        ],
      ),
    );
  }
}

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