Android使用BottomNavigationBar实现底部导航栏

 <com.ashokvarma.bottomnavigation.bottomnavigationbar
    android:layout_gravity="bottom"
    android:id="@+id/bottom_navigation_bar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"/>

bottomnavigationbar bottomnavigationbar = (bottomnavigationbar) findviewbyid(r.id.bottom_navigation_bar);
 
bottomnavigationbar
        .additem(new bottomnavigationitem(r.drawable.ic_home_white_24dp, "home"))
        .additem(new bottomnavigationitem(r.drawable.ic_book_white_24dp, "books"))
        .additem(new bottomnavigationitem(r.drawable.ic_music_note_white_24dp, "music"))
        .additem(new bottomnavigationitem(r.drawable.ic_tv_white_24dp, "movies & tv"))
        .additem(new bottomnavigationitem(r.drawable.ic_videogame_asset_white_24dp, "games"))
        .initialise();

 bottomnavigationbar.settabselectedlistener(new bottomnavigationbar.ontabselectedlistener(){
      @override
      public void ontabselected(int position) {
      }
      @override
      public void ontabunselected(int position) {]
      }
      @override
      public void ontabreselected(int position) {
      }
    });

package com.android.xiaobai; 
 
import android.os.bundle; 
import android.support.annotation.nullable; 
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.util.log; 
 
import com.ashokvarma.bottomnavigation.bottomnavigationbar; 
import com.ashokvarma.bottomnavigation.bottomnavigationitem; 
 
import java.util.arraylist; 
 
import fragment.contactsfragment; 
import fragment.dongtaifragment; 
import fragment.msgfragment; 
 
/** 
 * created by xiaobai on 2018/1/31/031. 
 */ 
 
public class messageactivity extends appcompatactivity implements bottomnavigationbar.ontabselectedlistener { 
  private arraylist<fragment> fragments; 
  private bottomnavigationbar bottomnavigationbar; 
  private msgfragment msgfragment; 
  private contactsfragment contactsfragment; 
  private dongtaifragment dongtaifragment; 
  private fragmentmanager fragmentmanager; 
  private fragmenttransaction transaction; 
  int lastselectedposition = 0; 
 
  @override 
  protected void oncreate(@nullable bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.activty_message); 
 
    bottomnavigationbar = findviewbyid(r.id.bottom_navigation_bar); 
    init(); 
  } 
 
  private void init() { 
    //要先设计模式后再添加图标！ 
    //设置按钮模式 mode_fixed表示固定  mode_shifting表示转移 
    bottomnavigationbar.setmode(bottomnavigationbar.mode_fixed); 
    //设置背景风格 
    // background_style_static表示静态的 
    //background_style_ripple表示涟漪的，也就是可以变化的 ，跟随setactivecolor里面的颜色变化 
    bottomnavigationbar.setbackgroundstyle(bottomnavigationbar.background_style_ripple); 
    //添加并设置图标、图标的颜色和文字 
    bottomnavigationbar 
        .additem(new bottomnavigationitem(r.drawable.im_botton_message, "消息")).setactivecolor(r.color.blue) 
        .additem(new bottomnavigationitem(r.drawable.im_botton_contacts, "联系人")).setactivecolor(r.color.red) 
        .additem(new bottomnavigationitem(r.drawable.im_botton_dongtai, "动态")).setactivecolor(r.color.orign) 
        .setfirstselectedposition(lastselectedposition ) 
        .initialise(); 
 
    bottomnavigationbar.settabselectedlistener(this); 
    setdefaultfragment(); 
  } 
 
  //设置初始界面 
  private void setdefaultfragment() { 
    fragmentmanager = getsupportfragmentmanager(); 
    transaction = fragmentmanager.begintransaction(); 
    transaction.replace(r.id.layframe, msgfragment.newinstance("消息")); 
    transaction.commit(); 
  } 
 
  @override 
  public void ontabselected(int position) { 
    fragmentmanager = getsupportfragmentmanager(); 
    transaction = fragmentmanager.begintransaction(); 
    switch (position) { 
      case 0: 
        if (msgfragment == null) { 
          msgfragment = msgfragment.newinstance("消息"); 
        } 
        transaction.replace(r.id.layframe, msgfragment); 
        break; 
      case 1: 
        if (contactsfragment == null) { 
          contactsfragment = contactsfragment.newinstance("联系人"); 
        } 
        transaction.replace(r.id.layframe, contactsfragment); 
        break; 
      case 2: 
        if (dongtaifragment == null) { 
          dongtaifragment = dongtaifragment.newinstance("动态"); 
        } 
        transaction.replace(r.id.layframe, dongtaifragment); 
        break; 
      default: 
        break; 
    } 
    // 事务提交 
    transaction.commit(); 
  } 
 
  @override 
  public void ontabunselected(int position) { 
    log.d("dongtaifragment", "ontabunselected() called with: " + "position = [" + position + "]"); 
  } 
 
  @override 
  public void ontabreselected(int position) { 
 
  } 
} 

package fragment; 
 
import android.os.bundle; 
import android.support.annotation.nullable; 
import android.view.layoutinflater; 
import android.view.view; 
import android.view.viewgroup; 
import android.widget.textview; 
 
import com.android.xiaobai.r; 
 
/** 
 * created by xiaobai on 2018/1/31/031. 
 */ 
 
public class msgfragment extends basefragment { 
  /** 
   * 标志位，标志已经初始化完成 
   */ 
  private boolean isprepared; 
  /** 
   * 是否已被加载过一次，第二次就不再去请求数据了 
   */ 
  private boolean mhasloadedonce; 
  textview textview; 
  @nullable 
  @override 
  public view oncreateview(layoutinflater inflater, @nullable viewgroup container, @nullable bundle savedinstancestate) { 
    if (mview == null) { 
      // 需要inflate一个布局文件 填充fragment 
      mview = inflater.inflate(r.layout.fragment_msg, container, false); 
      initview(); 
      isprepared = true; 
//    实现懒加载 
      lazyload(); 
    } 
    //缓存的mview需要判断是否已经被加过parent， 如果有parent需要从parent删除，要不然会发生这个mview已经有parent的错误。 
    viewgroup parent = (viewgroup) mview.getparent(); 
    if (parent != null) { 
      parent.removeview(mview); 
    } 
 
    return mview; 
  } 
  /** 
   * 初始化控件 
   */ 
  private void initview() { 
 
  } 
 
  @override 
  public void lazyload() { 
    if (!isprepared || !isvisible || mhasloadedonce) { 
      return; 
    } 
    //填充各控件的数据 
    mhasloadedonce = true; 
  } 
  public static msgfragment newinstance(string param1) { 
    msgfragment fragment = new msgfragment(); 
    bundle args = new bundle(); 
    args.putstring("agrs1", param1); 
    fragment.setarguments(args); 
    return fragment; 
  } 
} 

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:orientation="vertical" 
  tools:context=".messageactivity"> 
 
  <framelayout 
    android:id="@+id/layframe" 
    android:layout_width="match_parent" 
    android:layout_height="0dp" 
    android:layout_weight="1" /> 
 
  <com.ashokvarma.bottomnavigation.bottomnavigationbar 
    android:id="@+id/bottom_navigation_bar" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_gravity="bottom" /> 
</linearlayout> 

package fragment; 
 
import android.support.v4.app.fragment; 
import android.view.view; 
 
 
/** 
 * created by xiaobai on 2018/1/31/031. 
 */ 
 
public abstract class basefragment extends fragment { 
  /** 
   * fragment当前状态是否可见 
   */ 
  public boolean isvisible; 
 
  /** 
   * inflate布局文件 返回的view 
   */ 
  public view mview; 
 
  /** 
   * 简化 findviewbyid 
   * 
   * @param viewid 
   * @param <t> 
   * @return 
   */ 
  protected <t extends view> t find(int viewid) { 
    return (t) mview.findviewbyid(viewid); 
  } 
 
  /** 
   * setuservisiblehint是在oncreateview之前调用的 
   * 设置fragment可见状态 
   */ 
  @override 
  public void setuservisiblehint(boolean isvisibletouser) { 
    super.setuservisiblehint(isvisibletouser); 
    /** 
     * 判断是否可见 
     */ 
    if (getuservisiblehint()) { 
      isvisible = true; 
      onvisible(); 
    } else { 
      isvisible = false; 
      oninvisible(); 
    } 
  } 
 
  /** 
   * 可见 
   */ 
  private void onvisible() { 
    lazyload(); 
  } 
 
  /** 
   * 不可见 
   */ 
  private void oninvisible() { 
  } 
 
  /** 
   * 延迟加载 
   * 子类必须重写此方法 
   */ 
  public abstract void lazyload(); 
}