android应用开发设计模式之代理模式

设计模式在软件设计中非常重要,目前发展中有23种模式,在Android(java)中我们也有必要对其有一定的了解.在后面的学习中,我也学习总结一下,希望大家批评指正.首先我们看看代理模式.我们以游戏中的例子进行分析.
      代理模式:对一些对象提供代理，以限制哪些对象去访问其它对象。
[java]
package com.jindegege.service;  
  
public interface buy_car {  
   public String buy_car();  
}
package com.jindegege.service;

public interface buy_car {
   public String buy_car();
}
新建一个People类，具有买车的行为，所以实现接口buy_car：
[java]
package com.jindegege.buy_car;

import com.jindegege.service.buy_car;

public class People implements buy_car {

    private int cash;
    private String username;

    public int getCash() {
        return cash;
    }

    public void setCash(int cash) {
        this.cash = cash;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

@Override
public String buy_car() {
  // TODO Auto-generated method stub  
  
  
   return   username + "买了一台新车";
}
    
}
package com.jindegege.buy_car;
import com.jindegege.service.buy_car;
public class People implements buy_car {
    private int cash;
    private String username;
    public int getCash() {
        return cash;
    }
    public void setCash(int cash) {
        this.cash = cash;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
@Override
public String buy_car() {
  // TODO Auto-generated method stub


   return   username + "买了一台新车";
}
  
}
people类不能拥有车，必须经过proxy代理类的认证，符合条件之后才可以拥有车辆，新建一个代理，这个代理类来考察当前的people是否有资格进行买车：
[java]
package com.jindegege.buy_car;

import com.jindegege.service.buy_car;

public class buy_car_impl implements buy_car {
    private People people;

    public People getPeople() {
        return people;
    }

    public void setPeople(People people) {
        this.people = people;
    }

    public String buy_car() {
        if (people.getCash() > 2000) {
           return people.getUsername() + "花" + people.getCash()+ "块买了新车,交易结束!";
        } else {
            return people.getUsername() + "金钱不够，请继续比赛!";
        }
        
    }
package com.jindegege.buy_car;
import com.jindegege.service.buy_car;
public class buy_car_impl implements buy_car {
private People people;
    public People getPeople() {
        return people;
    }
    public void setPeople(People people) {
        this.people = people;
    }
    public String buy_car() {
        if (people.getCash() > 2000) {
           return people.getUsername() + "花" + people.getCash()+ "块买了新车,交易结束!";
        } else {
            return people.getUsername() + "金钱不够，请继续比赛!";
        }
      
    }

下面我们创建一个andriod客户端(控制层),用来控制前面的业务层,先给出一个简单的xml
[java]
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
    Android:layout_width="fill_parent"
    Android:layout_height="fill_parent"
    Android:orientation="vertical" >

    <TextView
        Android:id="@+id/textview01"
        Android:layout_width="fill_parent"
        Android:layout_height="wrap_content"
        Android:text="@string/hello" />
    <TextView
        Android:id="@+id/textview02"
        Android:layout_width="fill_parent"
        Android:layout_height="wrap_content"
        Android:text="@string/hello" />

</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
    Android:layout_width="fill_parent"
    Android:layout_height="fill_parent"
    Android:orientation="vertical" >
    <TextView
        Android:id="@+id/textview01"
        Android:layout_width="fill_parent"
        Android:layout_height="wrap_content"
        Android:text="@string/hello" />
    <TextView
        Android:id="@+id/textview02"
        Android:layout_width="fill_parent"
        Android:layout_height="wrap_content"
        Android:text="@string/hello" />
</LinearLayout>

然后给出这个activity
[java]
package com.jindegege.activity;

import com.jindegege.buy_car.People;
import com.jindegege.buy_car.buy_car_impl;

import Android.app.Activity;
import Android.os.Bundle;
import Android.util.Log;
import Android.widget.TextView;


public class ProxyActivity extends Activity {
    /** Called when the activity is first created. */
    private People people1;
    private People people2;
    private People people3;
    private buy_car_impl impl;
    private static final String TAG1="people1";
    private static final String TAG2="people2";
    private TextView textview01;
    private TextView textview02;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        textview01 =(TextView)findViewById(R.id.textview01);
        textview02 =(TextView)findViewById(R.id.textview02);
        people1 = new People();
        people1.setCash(5000);
        people1.setUsername("jindegege");

        people2 = new People();
        people2.setCash(200);
        people2.setUsername("biyumeimei");

        impl = new buy_car_impl();
        impl.setPeople(people1);
        impl.buy_car();
        String data1=impl.buy_car();
        //Log.i(TAG1,data1);  
        textview01.setText(data1);

        impl.setPeople(people2);
        String data2= impl.buy_car();
        //Log.i(TAG2,data2);  
        textview02.setText(data2);


    }
}
package com.jindegege.activity;
import com.jindegege.buy_car.People;
import com.jindegege.buy_car.buy_car_impl;
import Android.app.Activity;
import Android.os.Bundle;
import Android.util.Log;
import Android.widget.TextView;

public class ProxyActivity extends Activity {
    /** Called when the activity is first created. */
private People people1;
private People people2;
private People people3;
private buy_car_impl impl;
private static final String TAG1="people1";
private static final String TAG2="people2";
private TextView textview01;
private TextView textview02;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        textview01 =(TextView)findViewById(R.id.textview01);
        textview02 =(TextView)findViewById(R.id.textview02);
        people1 = new People();
        people1.setCash(5000);
        people1.setUsername("jindegege");
        people2 = new People();
        people2.setCash(200);
        people2.setUsername("biyumeimei");
        impl = new buy_car_impl();
        impl.setPeople(people1);
        impl.buy_car();
        String data1=impl.buy_car();
        //Log.i(TAG1,data1);
        textview01.setText(data1);
        impl.setPeople(people2);
        String data2= impl.buy_car();
        //Log.i(TAG2,data2);
        textview02.setText(data2);

    }
}
下面看看效果图: