Android bottom navigation bar implementation (Part 2) RadioGroup

Here is a brief record of the implementation of the Android bottom navigation bar through RadioGroup+Fragment.

layout:

 <?xml version= "1.0" encoding= "utf-8" ?>
 <RelativeLayout xmlns:android= "http://schemas.android.com/apk/res/android"  
                android:layout_width= "match_parent"  
                android:layout_height= "match_parent"  
                android:orientation= "vertical" > 
 
    <include layout= "@layout/fragment_content" /> 
 
 < View  
        android:layout_width= "match_parent"  
        android:layout_height= "1px"  
        android:background= "@color/grey_300"  
        android:elevation= "20dp" /> 
 
 <RadioGroup
        android:id= "@+id/radio_group"  
        android:layout_width= "match_parent"  
        android:layout_height= "56dp"  
        android:layout_alignParentBottom= "true"  
        android:background= "@color/white"  
        android:orientation= "horizontal" > 
 
 <RadioButton
            android:id= "@+id/rb_home"  
            style= "@style/radiobutton_style"  
            android:checked= "true"  
            android:drawableTop= "@drawable/radiobutton_bg_home"  
            android:text= "@string/item_home"  
 /> 
 
 <RadioButton
            android:id= "@+id/rb_location"  
            style= "@style/radiobutton_style"  
            android:drawableTop= "@drawable/radiobutton_bg_location"  
            android:text= "@string/item_location" /> 
 
 <RadioButton
            android:id= "@+id/rb_like"  
            style= "@style/radiobutton_style"  
            android:drawableTop= "@drawable/radiobutton_bg_like"  
            android:text= "@string/item_like" /> 
 
 <RadioButton
            android:id= "@+id/rb_me"  
            style= "@style/radiobutton_style"  
            android:drawableTop= "@drawable/radiobutton_bg_me"  
            android:text= "@string/item_person" /> 
 
 </RadioGroup>
 </RelativeLayout>

Here the drawableTop uses a state selector

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

style

 <style name = "radiobutton_style" >
        <item name = "android:layout_width" >0dp</item>
        <item name = "android:padding" >3dp</item>
        <item name = "android:layout_height" >match_parent</item>
        <item name = "android:layout_weight" >1</item>
 <item name = "android:button" >@ null </item><! --Remove the default dot of RadioButton-->  
        <item name = "android:gravity" >center</item>
        <item name = "android:textSize" >12sp</item>
 </style>

Code

The initialization code is not recorded, it is all findViewById, and the implementation process is nothing more than monitoring the RadioButton:

 mRadioGroup.setOnCheckedChangeListener(this); 
 
 
 @Override
 public void onCheckedChanged(RadioGroup group , int checkId) {
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
 switch (checkId) {
 case R.id.rb_home:
                if (mHomeFragment == null ) {
                    mHomeFragment = HomeFragment.newInstance(getString(R.string.item_home));
 }
 transaction .replace ( R.id.sub_content , mHomeFragment);
 break;
 case R.id.rb_location:
                if (mLocationFragment == null ) {
                    mLocationFragment = LocationFragment.newInstance(getString(R.string.item_location));
 }
 transaction .replace ( R.id.sub_content , mLocationFragment);
 break;
 case R.id.rb_like:
                if (mLikeFragment == null ) {
                    mLikeFragment = LikeFragment.newInstance(getString(R.string.item_like));
 }
 transaction .replace ( R.id.sub_content , mLikeFragment);
 break;
 case R.id.rb_me:
                if (mPersonFragment == null ) {
                    mPersonFragment = PersonFragment.newInstance(getString(R.string.item_person));
 }
 transaction .replace ( R.id.sub_content , mPersonFragment);
 break;
 }
 setTabState(); //Set state
 transaction . commit ();
 }

Status settings

 private void setTabState() {
 setHomeState();
 setLocationState();
 setLikeState();
 setMeState(); 
 
 } 
 
 /**
 * set tab home state
 */
    private void setHomeState() {
        if (mRadioHome.isChecked()) {
            mRadioHome.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary));
 } else {
            mRadioHome.setTextColor(ContextCompat.getColor(getActivity(), R.color.black));
 }
 } 
 
    private void setLocationState() {
        if (mRadioLocation.isChecked()) {
            mRadioLocation.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary));
 } else {
            mRadioLocation.setTextColor(ContextCompat.getColor(getActivity(), R.color.black));
 }
 } 
 
    private void setLikeState() {
        if (mRadioLike.isChecked()) {
            mRadioLike.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary));
 } else {
            mRadioLike.setTextColor(ContextCompat.getColor(getActivity(), R.color.black));
 }
 } 
 
    private void setMeState() {
        if (mRadioMe.isChecked()) {
            mRadioMe.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary));
 } else {
            mRadioMe.setTextColor(ContextCompat.getColor(getActivity(), R.color.black));
 }
 }

It should be noted here that setDefaultFragment(); I wrote in onCreateVew and it did not take effect. Here I wrote it in the onStart() method.

 @Override
 public void onStart() {
 setDefaultFragment(); //Write in onCreateView, it will not take effect when the page runs to other Fragments and then comes back
 super.onStart();
 }

Note: These articles do not have too much text description, because these things are not very difficult, and they are commonly used. I believe that many people are familiar with them. It is nonsense to say more. It is clearer to read the code directly.