70、电视菜单绘制方案

这个电视菜单绘制方案这里讲一下demo的实现方案

①首先模拟菜单数据。在真实编程中，这里应该是存放在本地数据库或者其他位置的真实菜单数据，由于是demo，所以这里是模拟数据

②然后通过fastJson将json数据（就是上一步模拟的json字符串）转换成对象的列表，这里的对象指的是需要展示在电视上的『展示项目』，比如说图片、线、『鱼香肉丝』等

③遍历对象列表，通过调用MenuManager中的paint方法，根据传入绘制工厂的item的类型，调用不同的绘制方法实现绘图。

以上就是demo的实现方案。

如果要想商业化使用，需要实现以下几个点：

①菜单的切换，这一块主要是展示时菜单的清空和重绘

②菜单的读取，需要能够快速并且无误的完成读写操作

③菜单信息的自动刷新，后台运行service定时从服务器获取售罄菜品列表，和本地菜品列表进行对比，找到应该标为售罄和取消售罄的列表并实现绘制

1、MenuActivity 处理菜单的类

        String demoData = "{
" +
                "    "menu_type": 0,
" +
                "    "date": "",
" +
                "    "day": "",
" +
                "    "time_bucket_name": "午餐",
" +
                "    "time_bucket_id": "31",
" +
                "    "list": [
" +
                "        {
" +
                "            "item_type": 0,
" +
                "            "item_id": 1,
" +
                "            "content": "干货",
" +
                "            "x": 10,
" +
                "            "y": 80.5,
" +
                "            "font_size": 30,
" +
                "            "font_type": 0,
" +
                "            "color": "#ffffff"
" +
                "        },
" +
                "        {
" +
                "            "item_type": 1,
" +
                "            "item_id": 2,
" +
                "            "content": "肉夹馍",
" +
                "            "x": 100,
" +
                "            "y": 80.5,
" +
                "            "font_size": 30,
" +
                "            "font_type": 1,
" +
                "            "color": "#000000",
" +
                "            "chargeitem_id": 341,
" +
                "            "price": 12.5,
" +
                "            "show_price": 0,
" +
                "            "indent": 350,
" +
                "            "dynamic_price": 0,
" +
                "            "dynamic_content": 1
" +
                "        },
" +
                "        {
" +
                "            "item_type": 1,
" +
                "            "item_id": 3,
" +
                "            "content": "好吃的肉夹馍",
" +
                "            "x": 400,
" +
                "            "y": 180,
" +
                "            "font_size": 30,
" +
                "            "font_type": 0,
" +
                "            "color": "#000000",
" +
                "            "chargeitem_id": 341,
" +
                "            "price": 12,
" +
                "            "show_price": 1,
" +
                "            "indent": 400,
" +
                "            "dynamic_price": 1,
" +
                "            "dynamic_content": 1
" +
                "        },
" +
                "        {
" +
                "            "item_type": 2,
" +
                "            "item_id": 4,
" +
                "            "x": 0,
" +
                "            "y": 400,
" +
                "            "width": 2048
" +
                "        },
" +
                "        {
" +
                "            "item_type": 3,
" +
                "            "item_id": 5,
" +
                "            "x": 500,
" +
                "            "y": 20,
" +
                "            "height": 1000
" +
                "        },
" +
                "        {
" +
                "            "item_type": 4,
" +
                "            "item_id": 6,
" +
                "            "x": 100,
" +
                "            "y": 200,
" +
                "            "width": 300,
" +
                "            "height": 300,
" +
                "            "src": "http://7rflgy.com1.z0.glb.clouddn.com/image-14.jpg"
" +
                "        },
" +
                "        {
" +
                "            "item_type": 5,
" +
                "            "item_id": 7,
" +
                "            "src": "http://7rflgy.com1.z0.glb.clouddn.com/blackboard.jpeg",
" +
                "            "laying_mode": 0
" +
                "        }
" +
                "    ]
" +
                "}";//假设这里是从服务器获取到的某天某个营业时间段的菜单数据

        int length = demoData.getBytes().length*4;

        JSONObject objDemo = JSON.parseObject(demoData);
        com.alibaba.fastjson.JSONArray arrayDemo = objDemo.getJSONArray("list");
        List<DisplayMenuItem> list = com.alibaba.fastjson.JSONArray.parseArray(arrayDemo.toJSONString(), DisplayMenuItem.class);//通过fastJson解析数组中的每个元素，得到的是某个菜单的所有『展示项目』的一个集合

        MenuManager.getInstance().showMenu(list);
　　

2、 MenuManager

 /**
     * 显示菜单，并更新本地的绑定id列表
     *
     * @param displayMenuItemList
     */
    public void showMenu(List<DisplayMenuItem> displayMenuItemList) {
        mapServerWidgetMatchId.clear();
        for (DisplayMenuItem item : displayMenuItemList) {

            PaintFactory.getPaint(item).paint(rlMain, ivMain);//绘制工厂类根据item的类型在rlMain上进行绘制
            if (item.item_type == MenuActivity.ItemTypeMenu) {
                if (item.chargeitem_id != -1 && item.chargeitem_id != 0) {
                    mapServerWidgetMatchId.put(item.chargeitem_id, item.item_id);//如果是被关联到服务器上的，记录在Map中，用来动态售罄信息
                }
            }
        }
        CommonUtils.LogWuwei("","size is "+mapServerWidgetMatchId.keySet().size());
    }

　　

3、绘制工厂类PaintFactory

/**
 * author: Created by zzl on 16/1/8.
 */
public class PaintFactory {

    public static Context ctxt;
    public static int fenbianlv[]= new int[2];
    public static double x_fraction;
    public static double y_fraction;
    public static Typeface fontFaceChalkBoard;

    public static void init()
    {
        ctxt = MainApplication.getContext();
        fenbianlv = CommonUtils.getScreenWidthAndHeight(MainApplication.getmActivity());
        x_fraction = fenbianlv[0] / 1920.0;
        y_fraction = fenbianlv[1] / 1080.0;
        fontFaceChalkBoard = Typeface.createFromAsset(MainApplication.getmActivity().getAssets(), "fonts/pianpina.ttf");
    }

    public static BasePaint getPaint(DisplayMenuItem item)
    {
        switch (item.item_type)//根据item的类型调用不同的方法完成绘制
        {
            case MenuActivity.ItemTypeText:
                return new PaintText(item);
            case MenuActivity.ItemTypeMenu:
                return new PaintMenuItem(item);
            case MenuActivity.ItemTypeHorizontalLine:
                return new PaintHorizontalLine(item);
            case MenuActivity.ItemTypeVerticalLine:
                return new PaintVerticalLine(item);
            case MenuActivity.ItemTypePicture:
                return new PaintPic(item);
            case MenuActivity.ItemTypeBackgroundPic:
                return new PaintBackgroundPic(item);
        }
        return  null;
    }
}