Android 底部菜单栏（RadioGroup+Fragment）美化

package com.wajin.wajinlivingarea.ui; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.support.v7.app.AppCompatActivity; import android.view.KeyEvent; import android.widget.FrameLayout; import android.widget.RadioGroup; import com.wajin.wajinlivingarea.R; public class MainActivity extends AppCompatActivity { private FrameLayout frameLayout; private RadioGroup radioGroup; private Fragment[] mFragments; private int mIndex; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initFragment(); setRadioGroupListener(); } private void initFragment() { radioGroup = (RadioGroup) findViewById(R.id.radioGroup); frameLayout = (FrameLayout) findViewById(R.id.fl_content); HomeFragment homeFragment = new HomeFragment(); ShopFragment shopFragment = new ShopFragment(); LiveFragment liveFragment = new LiveFragment(); ShoppingCarFragment shoppingCarFragment = new ShoppingCarFragment(); MineFragment mineFragment = new MineFragment(); //添加到数组 mFragments = new Fragment[]{homeFragment, shopFragment, liveFragment, shoppingCarFragment, mineFragment}; //开启事务 FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); //添加首页 ft.add(R.id.fl_content, homeFragment).commit(); //默认设置为第0个 setIndexSelected(0); } private void setIndexSelected(int index) { if (mIndex == index) { return; } FragmentManager fragmentManager = getSupportFragmentManager(); FragmentTransaction ft = fragmentManager.beginTransaction(); //隐藏 ft.hide(mFragments[mIndex]); //判断是否添加 if (!mFragments[index].isAdded()) { ft.add(R.id.fl_content, mFragments[index]).show(mFragments[index]); } else { ft.show(mFragments[index]); } ft.commit(); //再次赋值 mIndex = index; } private void setRadioGroupListener() { radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup radioGroup, int i) { switch (i) { case R.id.rb_home: setIndexSelected(0); break; case R.id.rb_shop: setIndexSelected(1); break; case R.id.rb_live: setIndexSelected(2); break; case R.id.rb_shopping_car: setIndexSelected(3); break; case R.id.rb_mine: setIndexSelected(4); break; default: setIndexSelected(0); break; } } }); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK) { //仅当activity为task根（即首个启动activity）时才生效,这个方法不会改变task中的activity状态， // 按下返回键的作用跟按下HOME效果一样；重新点击应用还是回到应用退出前的状态； moveTaskToBack(false); return true; } return super.onKeyDown(keyCode, event); } }