使用RadioButton+Fragment实现底部导航栏效果

package com.example.jackhu.radiobuttondemo.fragment;


import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.jackhu.radiobuttondemo.R;

/**
 * A simple {@link Fragment} subclass.
 */
public class HomeFragment extends Fragment {


 public HomeFragment() {
  // Required empty public constructor
 }

 //单例模式
 public static HomeFragment newInstance(){
  HomeFragment homeFragment=new HomeFragment();
  return homeFragment;
 }

 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
  // Inflate the layout for this fragment
  return inflater.inflate(R.layout.fragment_home, container, false);
 }

}

package com.example.jackhu.radiobuttondemo;

import android.support.annotation.IdRes;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

import com.example.jackhu.radiobuttondemo.fragment.FindFragment;
import com.example.jackhu.radiobuttondemo.fragment.HomeFragment;
import com.example.jackhu.radiobuttondemo.fragment.MessageFragment;
import com.example.jackhu.radiobuttondemo.fragment.MyFragment;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {

 private RadioGroup mRadioGroup;
 private List fragments = new ArrayList<>();
 private Fragment fragment;
 private FragmentManager fm;
 private FragmentTransaction transaction;
 private RadioButton rb_Home,rb_Message,rb_Find,rb_My;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initView(); //初始化组件
  mRadioGroup.setOnCheckedChangeListener(this); //点击事件
  fragments = getFragments(); //添加布局
  //添加默认布局
  normalFragment();
 }

 //默认布局
 private void normalFragment() {
  fm=getSupportFragmentManager();
  transaction=fm.beginTransaction();
  fragment=fragments.get(0);
  transaction.replace(R.id.mFragment,fragment);
  transaction.commit();
 }

 private void initView() {
  mRadioGroup = (RadioGroup) findViewById(R.id.mRadioGroup);
  rb_Home= (RadioButton) findViewById(R.id.mRb_home);
  rb_Message= (RadioButton) findViewById(R.id.mRb_message);
  rb_Find= (RadioButton) findViewById(R.id.mRb_find);
  rb_My= (RadioButton) findViewById(R.id.mRb_my);
 }

 @Override
 public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
  fm=getSupportFragmentManager();
  transaction=fm.beginTransaction();
  switch (checkedId){
   case R.id.mRb_home:
    fragment=fragments.get(0);
    transaction.replace(R.id.mFragment,fragment);
    Toast.makeText(this, "Home", Toast.LENGTH_SHORT).show();
    break;
   case R.id.mRb_message:
    fragment=fragments.get(1);
    transaction.replace(R.id.mFragment,fragment);
    Toast.makeText(this, "Message", Toast.LENGTH_SHORT).show();
    break;
   case R.id.mRb_find:
    fragment=fragments.get(2);
    transaction.replace(R.id.mFragment,fragment);
    Toast.makeText(this, "Find", Toast.LENGTH_SHORT).show();
    break;
   case R.id.mRb_my:
    fragment=fragments.get(3);
    transaction.replace(R.id.mFragment,fragment);
    Toast.makeText(this, "My", Toast.LENGTH_SHORT).show();
    break;
  }
  setTabState();
  transaction.commit();
 }

 //设置选中和未选择的状态
 private void setTabState() {
  setHomeState();
  setMessageState();
  setFindState();
  setMyState();
 }

 private void setMyState() {
  if (rb_My.isChecked()){
   rb_My.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
  }else{
   rb_My.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
  }
 }

 private void setFindState() {
  if (rb_Find.isChecked()){
   rb_Find.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
  }else{
   rb_Find.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
  }
 }

 private void setMessageState() {
  if (rb_Message.isChecked()){
   rb_Message.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
  }else{
   rb_Message.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
  }
 }

 private void setHomeState() {
  if (rb_Home.isChecked()){
   rb_Home.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
  }else{
   rb_Home.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
  }
 }

 public List getFragments() {
  fragments.add(new HomeFragment());
  fragments.add(new MessageFragment());
  fragments.add(new FindFragment());
  fragments.add(new MyFragment());
  return fragments;
 }
}