这里简单记录一下Android底部导航栏通过RadioGroup+Fragment的实现。

布局：

1. <?xml version="1.0" encoding="utf-8"?> 
2. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
3.                 android:layout_width="match_parent" 
4.                 android:layout_height="match_parent" 
5.                 android:orientation="vertical"> 
6.  
7.     <include layout="@layout/fragment_content"/> 
8.  
9.     <View 
10.         android:layout_width="match_parent" 
11.         android:layout_height="1px" 
12.         android:background="@color/grey_300" 
13.         android:elevation="20dp"/> 
14.  
15.     <RadioGroup 
16.         android:id="@+id/radio_group" 
17.         android:layout_width="match_parent" 
18.         android:layout_height="56dp" 
19.         android:layout_alignParentBottom="true" 
20.         android:background="@color/white" 
21.         android:orientation="horizontal"> 
22.  
23.         <RadioButton 
24.             android:id="@+id/rb_home" 
25.             style="@style/radiobutton_style" 
26.             android:checked="true" 
27.             android:drawableTop="@drawable/radiobutton_bg_home" 
28.             android:text="@string/item_home" 
29.             /> 
30.  
31.         <RadioButton 
32.             android:id="@+id/rb_location" 
33.             style="@style/radiobutton_style" 
34.             android:drawableTop="@drawable/radiobutton_bg_location" 
35.             android:text="@string/item_location"/> 
36.  
37.         <RadioButton 
38.             android:id="@+id/rb_like" 
39.             style="@style/radiobutton_style" 
40.             android:drawableTop="@drawable/radiobutton_bg_like" 
41.             android:text="@string/item_like"/> 
42.  
43.         <RadioButton 
44.             android:id="@+id/rb_me" 
45.             style="@style/radiobutton_style" 
46.             android:drawableTop="@drawable/radiobutton_bg_me" 
47.             android:text="@string/item_person"/> 
48.  
49.     </RadioGroup> 
50. </RelativeLayout>  

这里的drawableTop使用了状态选择器

1. <selector xmlns:android="http://schemas.android.com/apk/res/android"> 
2.     <item android:drawable="@drawable/home_fill" android:state_checked="true"/> 
3.     <item android:drawable="@drawable/home"/> 
4. </selector>  

style

1. <style name="radiobutton_style"> 
2.         <item name="android:layout_width">0dp</item> 
3.         <item name="android:padding">3dp</item> 
4.         <item name="android:layout_height">match_parent</item> 
5.         <item name="android:layout_weight">1</item> 
6.         <item name="android:button">@null</item><!--去除RadioButton默认带的圆点--> 
7.         <item name="android:gravity">center</item> 
8.         <item name="android:textSize">12sp</item> 
9.     </style>  

代码

初始化的代码就不记录了，都是一些findViewById,实现过程无非就是对RadioButton进行监听一下：

1. mRadioGroup.setOnCheckedChangeListener(this); 
2.  
3.  
4.     @Override 
5.     public void onCheckedChanged(RadioGroup group, int checkId) { 
6.         FragmentTransaction transaction = getFragmentManager().beginTransaction(); 
7.         switch (checkId) { 
8.             case R.id.rb_home: 
9.                 if (mHomeFragment == null) { 
10.                     mHomeFragment = HomeFragment.newInstance(getString(R.string.item_home)); 
11.                 } 
12.                 transaction.replace(R.id.sub_content, mHomeFragment); 
13.                 break; 
14.             case R.id.rb_location: 
15.                 if (mLocationFragment == null) { 
16.                     mLocationFragment = LocationFragment.newInstance(getString(R.string.item_location)); 
17.                 } 
18.                 transaction.replace(R.id.sub_content, mLocationFragment); 
19.                 break; 
20.             case R.id.rb_like: 
21.                 if (mLikeFragment == null) { 
22.                     mLikeFragment = LikeFragment.newInstance(getString(R.string.item_like)); 
23.                 } 
24.                 transaction.replace(R.id.sub_content, mLikeFragment); 
25.                 break; 
26.             case R.id.rb_me: 
27.                 if (mPersonFragment == null) { 
28.                     mPersonFragment = PersonFragment.newInstance(getString(R.string.item_person)); 
29.                 } 
30.                 transaction.replace(R.id.sub_content, mPersonFragment); 
31.                 break; 
32.         } 
33.         setTabState();//设置状态 
34.         transaction.commit(); 
35.     }  

状态的设置

1. private void setTabState() { 
2.         setHomeState(); 
3.         setLocationState(); 
4.         setLikeState(); 
5.         setMeState(); 
6.  
7.     } 
8.  
9.     /** 
10.      * set tab home state 
11.      */ 
12.     private void setHomeState() { 
13.         if (mRadioHome.isChecked()) { 
14.             mRadioHome.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary)); 
15.         } else { 
16.             mRadioHome.setTextColor(ContextCompat.getColor(getActivity(), R.color.black)); 
17.         } 
18.     } 
19.  
20.     private void setLocationState() { 
21.         if (mRadioLocation.isChecked()) { 
22.             mRadioLocation.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary)); 
23.         } else { 
24.             mRadioLocation.setTextColor(ContextCompat.getColor(getActivity(), R.color.black)); 
25.         } 
26.     } 
27.  
28.     private void setLikeState() { 
29.         if (mRadioLike.isChecked()) { 
30.             mRadioLike.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary)); 
31.         } else { 
32.             mRadioLike.setTextColor(ContextCompat.getColor(getActivity(), R.color.black)); 
33.         } 
34.     } 
35.  
36.     private void setMeState() { 
37.         if (mRadioMe.isChecked()) { 
38.             mRadioMe.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary)); 
39.         } else { 
40.             mRadioMe.setTextColor(ContextCompat.getColor(getActivity(), R.color.black)); 
41.         } 
42.     }  

这里需要注意的是， setDefaultFragment();我写在onCreateVew里面并没有生效。这里我写在了onStart()方法里了。

1. @Override 
2.    public void onStart() { 
3.        setDefaultFragment();//写在onCreateView里面，当页面跑到其他Fragment再回来就不会生效 
4.        super.onStart(); 
5.    }  

说明：这几篇文章没有过多的文字叙述，因为这些东西也不是很难，而且都是常用的，相信很多人都了如指掌了，多说亦是废话，直接上代码看的反而更清楚。