基于TabLayout中的Tab间隔设置方法(实例讲解)

<android.support.design.widget.TabLayout
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:id="@+id/tl_download_tabs"
  android:layout_width="wrap_content"
  android:layout_height="30dp"
  android:layout_marginTop="10dp"
  android:layout_gravity="center_horizontal"
  android:overScrollMode="never"
  app:tabMode="fixed"
  app:tabPaddingStart="30dp"
  app:tabPaddingEnd="30dp"
  app:tabIndicatorHeight="0dp"
  app:tabBackground="@drawable/download_tab_bg_selector"
  app:tabSelectedTextColor="#000000"
  app:tabTextColor="#ffffff"/>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:state_selected="true">
  <!--<shape>
   <solid android:color="#ffffff"/>
   <corners android:topLeftRadius="10dp" android:topRightRadius="10dp" />
  </shape>-->
  <!--为了让TabLayout内部的Tab有间隔，暂时找不到其他设置方法，只能在背景图形里面设置间隔-->
  <layer-list>
   <item>
    <shape>
     <solid android:color="@android:color/transparent"/>
    </shape>
   </item>
   <item android:left="5dp" android:right="5dp">
    <shape>
     <corners android:topLeftRadius="10dp" android:topRightRadius="10dp" />
     <solid android:color="#ffffff"/>
    </shape>
   </item>
  </layer-list>
 </item>
 <item android:state_selected="false">
  <!--<shape>
   <solid android:color="#bcbcbc"/>
   <corners android:topLeftRadius="10dp" android:topRightRadius="10dp" />
  </shape>-->
  <layer-list>
   <item>
    <shape>
     <solid android:color="@android:color/transparent"/>
    </shape>
   </item>
   <item android:left="5dp" android:right="5dp">
    <shape>
     <corners android:topLeftRadius="10dp" android:topRightRadius="10dp" />
     <solid android:color="#bcbcbc"/>
    </shape>
   </item>
  </layer-list>
 </item>
</selector>

TabLayout mTabLayout = (TabLayout) findViewById(R.id.tl_download_tabs);
  mTabLayout.addTab(mTabLayout.newTab().setText("已下载"));
  mTabLayout.addTab(mTabLayout.newTab().setText("下载中"));
  mTabLayout.setupWithViewPager(mViewPager);

@Override
  public CharSequence getPageTitle(int position) {
   if(position == 0){
    return "已下载";
   }else if(position == 1){
    return "下载中";
   }
   return "";
  }