Android使用BottomNavigationBar实现底部导航栏

compile ‘com.ashokvarma.android:bottom-navigation-bar:0.9.5'

 <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(); 
}