Android 中基于TabLayout+ViewPager实现标签卡效果

<?xml version="1.0" encoding="utf-8"?><LinearLayout 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:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical"  tools:context="com.plbear.yyj.myapplication.MainActivity">  <android.support.design.widget.TabLayout    android:id="@+id/tab"    android:layout_width="match_parent"    android:layout_height="40dp"    app:tabGravity="fill"    app:tabIndicatorColor="#4978ef"    app:tabIndicatorHeight="2dp"    app:tabMode="scrollable"    app:tabSelectedTextColor="#4978ef"    app:tabTextColor="#222222"></android.support.design.widget.TabLayout>  <android.support.v4.view.ViewPager    android:id="@+id/view_pager"    android:layout_width="match_parent"    android:layout_height="wrap_content"></android.support.v4.view.ViewPager></LinearLayout>

package com.plbear.yyj.myapplicationimport android.os.Bundleimport android.support.design.widget.Snackbarimport android.support.design.widget.TabLayoutimport android.support.v4.app.Fragmentimport android.support.v4.app.FragmentPagerAdapterimport android.support.v7.app.AppCompatActivityimport android.view.Menuimport android.view.MenuItemimport kotlinx.android.synthetic.main.activity_main.*class MainActivity : AppCompatActivity() {  var mFragList = ArrayList<Fragment>()  var adapter = object:FragmentPagerAdapter(supportFragmentManager){    override fun getItem(position: Int): Fragment {      return mFragList[position]    }    override fun getCount(): Int {      return 2    }  }  override fun onCreate(savedInstanceState: Bundle?) {    super.onCreate(savedInstanceState)    setContentView(R.layout.activity_main)    initViewPager() //先将各个fragment加入到viewpager中    initTabLayout(); //初始化tablayout  }  fun initTabLayout(){    tab.setupWithViewPager(view_pager)    tab.setTabsFromPagerAdapter(adapter)    tab.tabMode = TabLayout.MODE_FIXED    tab.getTabAt(0)?.setText("第一页")    tab.getTabAt(1)?.setText("第二页")  }  fun initViewPager(){    mFragList.add(Fragment1())    mFragList.add(Fragment2())    view_pager.adapter = adapter  }}