Fragment底部切换

一.效果

在这里插入图片描述

二.思路

四个radiobutton+4个fragent+动态hide和show指定的Fragment

三.代码

（1）创建4个Fragment，此处省略：

（2）activity_main.xml:

(3)MainActivity.java:

public class MainActivity extends AppCompatActivity {
       //视图    private MyViewPager vp;    private RadioGroup rg;    private RadioButton rb1,rb2,rb3,rb4;    //数据    private ArrayList
   
     fragmentArrayList=new ArrayList<>();    //记录当前正在显示的Fragment    private Fragment currentFragment;    @Override    protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);        //TODO 去除Bar        supportRequestWindowFeature(Window.FEATURE_NO_TITLE);//这句话一定要放到中间        setContentView(R.layout.activity_main);        initview();//找组件        initdata();//初始化数据        initlistener();//事件监听    }    private void initlistener() {
           rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
               @Override           public void onCheckedChanged(RadioGroup group, int checkedId) {
                   if(rb1.getId()==checkedId){
                       replaceFragemnt(fragmentArrayList.get(0));                }else  if(rb2.getId()==checkedId){
                       replaceFragemnt(fragmentArrayList.get(1));                }else if(rb3.getId()==checkedId){
                       replaceFragemnt(fragmentArrayList.get(2));                }else if(rb4.getId()==checkedId){
                       replaceFragemnt(fragmentArrayList.get(3));                }           }        });    }    private void initdata() {
           fragmentArrayList.add(new Fragment1());        fragmentArrayList.add(new Fragment2());        fragmentArrayList.add(new Fragment3());        fragmentArrayList.add(new Fragment4());    }    private void initview() {
           vp=findViewById(R.id.vp);        rg=findViewById(R.id.rg);        rb1=findViewById(R.id.rb1);        rb2=findViewById(R.id.rb2);        rb3=findViewById(R.id.rb3);        rb4=findViewById(R.id.rb4);    }    //TODO 替换Fragment的优化    public void replaceFragemnt(Fragment fragment){
           //TODO 1:获得管理者        FragmentManager supportFragmentManager = getSupportFragmentManager();        //TODO 2:开启事务        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();        //TODO 3:替换功能         //隐藏当前正在显示的fragment            if(currentFragment!=null){
                   fragmentTransaction.hide(currentFragment);            }        //判断要添加的fragment时候被添加过        if(fragment.isAdded()){
   //被添加过            //显示传过来            fragmentTransaction.show(fragment);        }else{
   //没有添加过            //添加传过来的            fragmentTransaction.add(R.id.frame_layout,fragment);        }        //TODO 4:提交        fragmentTransaction.commit();        //更新当前正在显示的Fragment        currentFragment=fragment;    }}