TabLayout+ViewPager实现标签卡效果

转载请注明原文地址：http://www.cnblogs.com/yanyojun/p/8082391.html

代码已经上传至Github：https://github.com/YanYoJun/ViewPagerDemo

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先看效果

1、布局文件

 <?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>

2、代码实现

 package com.plbear.yyj.myapplication

 import android.os.Bundle
 import android.support.design.widget.Snackbar
 import android.support.design.widget.TabLayout
 import android.support.v4.app.Fragment
 import android.support.v4.app.FragmentPagerAdapter
 import android.support.v7.app.AppCompatActivity
 import android.view.Menu
 import android.view.MenuItem

 import 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
     }

 }

这里需要注意点，需要先将setupWithViewPager和tablayout绑定起来，然后再初始化tab的标签页，这个非常重要，否则会造成tablayout中的文字显示不出来。

这里注意，要保证support包和design包的版本号一致，不然app会出现闪退

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
    compile 'com.android.support:design:26.0.0-beta1'
    compile 'com.android.support:support-v4:26.0.0-beta1'
    implementation 'com.android.support:appcompat-v7:26.0.0-beta1'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:0.5'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:2.2.2'
}