自定义控件中如何实现按钮之间的共轭？

 1 package com.example.weibo;
 2 
 3 import android.content.Context;
 4 import android.util.AttributeSet;
 5 import android.view.LayoutInflater;
 6 import android.view.View;
 7 import android.widget.ImageButton;
 8 import android.widget.LinearLayout;
 9 
10 
11 public class BottomLayout extends LinearLayout {
12     private ImageButton main;
13     private ImageButton add;
14     private ImageButton account;
15     
16     final int home_b = R.drawable.ic_home_black_48dp;
17     final int home_g = R.drawable.ic_home_grey600_48dp;
18     final int add_b = R.drawable.ic_add_circle_black_48dp;
19     final int add_g = R.drawable.ic_add_circle_grey600_48dp;
20     final int account_b = R.drawable.ic_account_box_black_48dp;
21     final int account_g = R.drawable.ic_account_box_grey600_48dp;
22     
23     public BottomLayout(Context context,AttributeSet attrs){
24         super(context,attrs);
25         LayoutInflater.from(context).inflate(R.layout.bottom,this);
26         main = (ImageButton)findViewById(R.id.bottom_main);
27         add = (ImageButton)findViewById(R.id.bottom_add);
28         account = (ImageButton)findViewById(R.id.bottom_account);
29         main.setTag("g");
30         add.setTag("g");
31         account.setTag("g");
32     
33         
34         
35         
36         main.setOnClickListener(new OnClickListener(){
37             @Override
38             public void onClick(View v){
39                 if (v.getTag()=="g")
40                 {
41                     ((ImageButton)v).setImageResource(home_b);
42                     v.setTag("b");
43                     add.setImageResource(add_g);
44                     add.setTag("g");
45                     account.setImageResource(account_g);
46                     account.setTag("g");
47                 }
48             }
49         });
50         add.setOnClickListener(new OnClickListener(){
51             @Override
52             public void onClick(View v){
53                 if (v.getTag()=="g")
54                 {
55                     ((ImageButton)v).setImageResource(add_b);
56                     v.setTag("b");
57                     main.setImageResource(home_g);
58                     main.setTag("g");
59                     account.setImageResource(account_g);
60                     account.setTag("g");
61                 }
62             }
63         });
64         account.setOnClickListener(new OnClickListener(){
65             @Override
66             public void onClick(View v){
67                 if (v.getTag()=="g")
68                 {
69                     ((ImageButton)v).setImageResource(account_b);
70                     v.setTag("b");
71                     add.setImageResource(add_g);
72                     add.setTag("g");
73                     main.setImageResource(home_g);
74                     main.setTag("g");
75                 }
76             }
77         });
78     
79     }
80 }