监听者模式

四人组笔记：监听者模式

1.一对多的关系

2.subject触发多个observe的更新

3.注意pull和push数据的方式。 本例使用pull，监听者按需获取数据，

4.添加subject是否需要通知observe的条件判断，IsChange() 63行。

代码规范：

改变老代码的地方，需要封装

针对接口编程

 

游戏中服务器和客户端的通信，可理解为监听者模式...

本测试：三个observe，使用数据pull，使用条件判断，使用输出模拟subject的更新

namespace DesignModeTest
{
class Program
{
static void Main(string[] args)
{
WeatherInfoClass weatherInfo = new WeatherInfoClass();
TemperatureClass temperatureTips = new TemperatureClass();
HumClass humTips = new HumClass();
WeatherClass weatherTips = new WeatherClass();

weatherInfo.AddObserver(temperatureTips);
weatherInfo.AddObserver(humTips);
weatherInfo.AddObserver(weatherTips);

weatherInfo.Updata(10, 1, WeatherType.Cloudy);
weatherInfo.Updata(30, 2, WeatherType.Sun);
weatherInfo.Updata(1, 1, WeatherType.Rain);

}

enum WeatherType
{
Sun = 1,//晴
Cloudy = 2,//阴
Rain = 3//雨
}
interface MySubject //被监听者需要有的
{
void AddObserver(MyObserver obj);
void ChangeData();
void RemoveObserver(MyObserver obj);
}
/// <summary>
/// 可监听者
/// </summary>
class WeatherInfoClass : MySubject
{
private const int LimitTemperature = 20;
private int mTemperature;//温度
private int mHum;//湿度
private WeatherType mWeather;

private List<MyObserver> mObserverList = new List<MyObserver>();

#region 监听者拉pull数据需要
public int GetTemperature()
{
return mTemperature;
}

public int GetHum()
{
return mHum;
}

public WeatherType GetWeather()
{
return mWeather;
}
#endregion

private bool IsChange()
{
if (mTemperature < LimitTemperature)
{
return true;
}
return false;
}

public void Updata(int temperature, int hum, WeatherType weathertype)
{
mTemperature = temperature;
mHum = hum;
mWeather = weathertype;

if (IsChange())
{
ChangeData();
}
}


public void AddObserver(MyObserver obj)
{
if (!mObserverList.Contains(obj))
{
mObserverList.Add(obj);
}
}

public void ChangeData()
{
for (int i = 0; i < mObserverList.Count; ++i)
{
mObserverList[i].Update(this);
}
}
public void RemoveObserver(MyObserver obj)
{
mObserverList.Remove(obj);
}

}


interface MyObserver
{
void Update(MySubject subject);
void Display();
}

class TemperatureClass : MyObserver
{
private int mTemperature;
private int mHum;

public void Update(MySubject subject)
{
WeatherInfoClass info = subject as WeatherInfoClass;
if (info != null)
{
mTemperature = info.GetTemperature();
mHum = info.GetHum();
Display();
}
}

public void Display()
{
Console.WriteLine("TemperatureClass 温度：" + mTemperature + " 湿度：" + mHum);
}
}

class HumClass : MyObserver
{
private int mHum;
public void Update(MySubject subject)
{
WeatherInfoClass info = subject as WeatherInfoClass;
if (info != null)
{
mHum = info.GetHum();
Display();
}
}

public void Display()
{
Console.WriteLine("HumClass 湿度：" + mHum);
}
}

class WeatherClass : MyObserver
{
private WeatherType mWeatherType;
public void Update(MySubject subject)
{
WeatherInfoClass info = subject as WeatherInfoClass;
if (info != null)
{
mWeatherType = info.GetWeather();

Display();
}
}

public void Display()
{
Console.WriteLine("WeatherClass 天气：" + mWeatherType);
}
}

}
}