使用BottomNavigationView组件完成底部导航栏
在AndroidStudio上新建activity时，有一个默认带有BottomNavigationView组件的activity，同时完成了一些初始化的一些操作。所以这里直接使用这些默认的代码，在此基础上我们使用FragmentTransaction完成对于Fragment的切换，
activity_index.java代码
package sportwin.heiyang.com.sportwinner.HomeAcitvity; import android.app.Activity; import android.graphics.Color; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.design.widget.BottomNavigationView; 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.Menu; import android.view.MenuItem; import android.view.View; import android.view.WindowManager; import android.widget.TextView; import android.widget.Toast; import sportwin.heiyang.com.sportwinner.R; public class IndexActivity extends AppCompatActivity implements Sports_communityFragment.OnFragmentInteractionListener,FindFragment.OnFragmentInteractionListener,SportFragment.OnFragmentInteractionListener,MyFragment.OnFragmentInteractionListener { private BottomNavigationView navigation; private FragmentManager fManager; private Fragment fragment_find; private Fragment fragment_sport; private Fragment fragment_sport_community; private Fragment fragment_my; private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_index); //设置一些系统参数 //透明状态栏 getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS); // setStatusBar(); //设置任务栏图标黑色 changStatusIconCollor(true); //设置fragment intiFragment(); navigation = findViewById(R.id.navigation); SetItemSelectedListener(); } //设置底部导航按钮的监听器 private void SetItemSelectedListener() { navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); navigation.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() { @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { fManager = getSupportFragmentManager(); FragmentTransaction fTransaction = fManager.beginTransaction(); hideAllFragment(fTransaction); //开始切换fragment System.out.println("开始切换Fragment"); switch (item.getItemId()) { case R.id.navigation_sports_community: if(fragment_sport_community == null){ fragment_sport_community = new Sports_communityFragment(); fTransaction.add(R.id.index_content,fragment_sport_community).commit(); System.out.println("添加展示运动圈页面"); }else{ fTransaction.show(fragment_sport_community).commit(); System.out.println("展示运动圈页面"); } return true; case R.id.navigation_find: if(fragment_find == null){ fragment_find = new FindFragment(); fTransaction.add(R.id.index_content,fragment_find).commit(); System.out.println("添加展示发现页面"); }else{ fTransaction.show(fragment_find).commit(); System.out.println("展示发现页面"); } return true; case R.id.navigation_sport: if(fragment_sport == null){ fragment_sport = new SportFragment(); fTransaction.add(R.id.index_content,fragment_sport).commit(); System.out.println("添加展示运动页面"); }else{ fTransaction.show(fragment_sport).commit(); System.out.println("展示运动页面"); } return true; case R.id.navigation_my: if(fragment_my == null){ fragment_my = new MyFragment(); fTransaction.add(R.id.index_content,fragment_my).commit(); System.out.println("添加展示我的页面"); }else{ fTransaction.show(fragment_my).commit(); System.out.println("展示我的页面"); } return true; } return false; } }); } //初始化Fragment private void intiFragment() { fragment_sport_community=new Sports_communityFragment(); //开始初始化第一个fragment System.out.println("开始初始化第一个fragment"); fManager = getSupportFragmentManager(); FragmentTransaction fTransaction = fManager.beginTransaction(); fTransaction.replace(R.id.index_content,fragment_sport_community); fTransaction.commit(); } //隐藏所有fragment private void hideAllFragment(FragmentTransaction fragmentTransaction){ if(fragment_sport_community != null)fragmentTransaction.hide(fragment_sport_community); if(fragment_find != null)fragmentTransaction.hide(fragment_find); if(fragment_sport != null)fragmentTransaction.hide(fragment_sport); if(fragment_my != null)fragmentTransaction.hide(fragment_my); } // 设置任务栏图标颜色为黑色 public void changStatusIconCollor(boolean setDark) { if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){ View decorView = getWindow().getDecorView(); if(decorView != null){ int vis = decorView.getSystemUiVisibility(); if(setDark){ vis |= View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR; } else{ vis &= ~View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR; } decorView.setSystemUiVisibility(vis); } } } @Override public void onFragmentInteraction(Uri uri) { } }
这里面四个Fragment的代码与布局不再展示，原因是自己写的十分粗糙，仅仅是实现了效果，你可以自己实现来进行替代，不会出现技术上问题。
需要注意的是，FragmentTransaction 每次使用的时候需要重新初始化，不能一次初始化后多次反复使用。
FragmentTransaction fTransaction = fManager.beginTransaction();
activity_index.xml代码：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="match_parent" android:layout_height="match_parent" android:clipToPadding="true" android:fitsSystemWindows="true" tools:context=".HomeAcitvity.IndexActivity"> <FrameLayout android:id="@+id/index_content" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_above="@+id/navigation" android:orientation="horizontal"> </FrameLayout> <android.support.design.widget.BottomNavigationView android:id="@+id/navigation" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentEnd="true" android:background="?android:attr/windowBackground" app:itemIconTint="@color/color_state_menu_navi" app:itemTextColor="@color/color_state_menu_navi" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:menu="@menu/navigation" /> </RelativeLayout >
xml代码中app:menu="@menu/navigation"对应文件在你新建那个默认的带有BottomNavigationView组件的activity时会自动创立，然后app:item的两个属性可以删掉，或者查看我往期的博客园可以了解相关信息。