百度人脸产品套件————壁虎 3.继电器控制

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本章开篇前，我对上一章的部分代码进行了重构

我将单例模式放到了BaseController中

现在BaseController如下：

[AddINotifyPropertyChangedInterface]
    public class BaseController<T> : INotifyPropertyChanged where T:new()
    {
        private static T instance;

        public static T Instance
        {
            get
            {
                if (instance == null)
                    instance = new T();
                return instance;
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged([CallerMemberName]string PropertyName="")
        {
            PropertyChanged(this, new PropertyChangedEventArgs(PropertyName));
        }
    }

LightController如下：

public class LightController : BaseController<LightController>
    {
        public LightController()
        {
            Brightness = 0;
        }

        private readonly string IOPath = "/sys/class/leds/wled/brightness";

        private int _brightness = 0;

        public int Brightness
        {
            get => _brightness;
            set
            {
                try
                {
                    value = value & 0xff;

                    byte[] b = Encoding.UTF8.GetBytes(value.ToString());

                    using (FileStream fs = new FileStream(IOPath, FileMode.Create))
                    {
                        fs.Write(b, 0, b.Length);
                    }

                    _brightness = value;
                }
                catch (Exception ex)
                {
                    Debugger.Break();
                }
            }
        }
    }

正篇开始

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本篇打算继上一篇的进度，继续进行外设的测试，接下去测试两组继电器。位于壁虎的最下侧接线端上。

点我查看外设物理定义

那本篇主要还是测试软件，因为继电器切换是有哒哒声，所以控制成功与否一听就知道啦
（继电器开机会重置（瞬开一次），注意默认开机后是关闭态，也就是外设接口不通的状态）

首先，仿照LightController书写RelayController

public class RelayController : BaseController<RelayController>
    {
        private readonly string Relay1Path = "/sys/exgpio/relay1";
        private readonly string Relay2Path = "/sys/exgpio/relay2";

        private bool relay1IsOpen = false;
        public bool Relay1IsOpen
        {
            get => relay1IsOpen;
            set
            {
                try
                {
                    if (relay1IsOpen == value)
                        return;

                    string target = "0";
                    if (value)
                        target = "1";

                    byte[] b = Encoding.UTF8.GetBytes(target.ToString());

                    using (FileStream fs = new FileStream(Relay1Path, FileMode.Create))
                    {
                        fs.Write(b, 0, b.Length);
                    }
                    relay1IsOpen = value;
                }
                catch
                {
                    Debugger.Break();
                }
            }
        }

        private bool relay2IsOpen = false;
        public bool Relay2IsOpen
        {
            get => relay2IsOpen;
            set
            {
                try
                {
                    if (relay2IsOpen == value)
                        return;

                    string target = "0";
                    if (value)
                        target = "1";

                    byte[] b = Encoding.UTF8.GetBytes(target.ToString());

                    using (FileStream fs = new FileStream(Relay2Path, FileMode.Create))
                    {
                        fs.Write(b, 0, b.Length);
                    }
                    relay2IsOpen = value;
                }
                catch
                {
                    Debugger.Break();
                }
            }
        }

        ~RelayController()
        {
            Relay1IsOpen = Relay2IsOpen = false;
        }
    }

然后开始重构UI部分

后台代码添加一个新的控制器

public partial class MainPage : ContentPage
    {
        public LightController LightController => LightController.Instance;

        public RelayController RelayController => RelayController.Instance;
        public MainPage()
        {
            InitializeComponent();
        }
    }

前端则重新对UI进行重构，添加新的UI。这里用switch来表达继电器的开关状态

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:GoJhou.Gekko"
             BackgroundColor="#FF303030"
             x:Name="GekkoTestPage"
             x:Class="GoJhou.Gekko.MainPage">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="15" />
        Grid.RowDefinitions>
        <StackLayout>
            
            <StackLayout>
                <StackLayout Margin="15"
                         HorizontalOptions="Center" 
                         Orientation="Horizontal">
                    <Label TextColor="White" Text="补光灯亮度:"/>
                    <Label TextColor="White" 
                       Text="{Binding Path=LightController.Brightness,Mode=OneWay}" 
                       BindingContext="{x:Reference GekkoTestPage}"/>
                StackLayout>
                <Slider x:Name="LightSlider"
                    Margin="5" 
                    Minimum="0" 
                    Maximum="100"
                    BindingContext="{x:Reference GekkoTestPage}"
                    Value="{Binding Path=LightController.Brightness}"
                    />
            StackLayout>
            
            
            <Grid Margin="0,100,0,0">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition/>
                Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                Grid.ColumnDefinitions>
                <Label TextColor="White"
                       HorizontalOptions="Center"
                       WidthRequest="120"
                       HorizontalTextAlignment="Center"
                       Text="Relay1"/>
                <Label TextColor="White"
                       Grid.Column="1"  
                       HorizontalOptions="Center"
                       WidthRequest="120"
                       HorizontalTextAlignment="Center"
                       Text="Relay2"/>
                <Switch Grid.Row="1" BindingContext="{x:Reference GekkoTestPage}" 
                       HorizontalOptions="Center"
                        ThumbColor="Gray"
                    IsToggled="{Binding RelayController.Relay1IsOpen}"/>
                <Switch Grid.Row="1"  Grid.Column="1"
                       HorizontalOptions="Center"
                        ThumbColor="Gray"
                    BindingContext="{x:Reference GekkoTestPage}" 
                    IsToggled="{Binding RelayController.Relay2IsOpen}"/>
            Grid>
        StackLayout>

        
        <StackLayout Grid.Row="2" VerticalOptions="End">
            
            <Label TextColor="LightGray" 
                   FontFamily="微软雅黑" 
                   Margin="15"
                   Text="© 2019 goJhou, Personal. All rights reserved. " 
                   HorizontalOptions="Center"
                   VerticalOptions="CenterAndExpand" />
        StackLayout>
    Grid>
ContentPage>

因为与灯光控制雷同，本篇的篇幅就稍微简单粗暴一些~