Android kotlin实现底部导航栏

1、实现效果，可点击或者滑动切换fragment

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 实现方法：

1、创建三个fragment.kt

2、创建fragmentAdapter

class MyFragmentAdapter(fragmentManager: FragmentManager, private val fragmentList: List<Fragment>, private val titleList: List<String>, private val context: Context) : FragmentPagerAdapter(fragmentManager) {

    override fun getItem(position: Int): Fragment {

        return fragmentList[position]
    }

    override fun getCount(): Int {
        return titleList.size
    }

    //注意！！！这里就是我们自定义的布局tab_item
    fun getCustomView(position: Int): View {
        val view = LayoutInflater.from(context).inflate(R.layout.tab_item, null)
        val iv = view.findViewById(R.id.tab_iv) as ImageView
        val tv = view.findViewById(R.id.tab_tv) as TextView
        when (position) {
            0 -> {
                //drawable代码在文章最后贴出
                iv.setImageDrawable(context.resources.getDrawable(R.drawable.home_icon_selector))
                tv.text = "首页"
            }
            1 -> {
                iv.setImageDrawable(context.resources.getDrawable(R.drawable.txl_icon_selector))
                tv.text = "通讯录"
            }
            2 -> {
                iv.setImageDrawable(context.resources.getDrawable(R.drawable.wd_icon_selector))
                tv.text = "我的"
            }
        }
        return view
    }
}

3、ViewPager加载fragment

 

private lateinit var fragment3:BlankFragment3
private lateinit var fragment2:BlankFragment2
private lateinit var fragment:BlankFragment

private fun getdata() {
    fragment  = BlankFragment()
    fragment2 = BlankFragment2()
    fragment3 = BlankFragment3()
    fragmentList!!.add(fragment)
    fragmentList!!.add(fragment2)
    fragmentList!!.add(fragment3)

    titleList!!.add("首页")
    titleList!!.add("通讯录")
    titleList!!.add("我的")

    activity_tablayout.setTabMode(TabLayout.MODE_FIXED)//不可以轮动

    activity_tablayout.addTab(activity_tablayout.newTab().setText(titleList!!.get(0)))
    activity_tablayout.addTab(activity_tablayout.newTab().setText(titleList!!.get(1)))
    activity_tablayout.addTab(activity_tablayout.newTab().setText(titleList!!.get(2)))

    activity_viewPager.adapter=MyFragmentAdapter(getSupportFragmentManager(), fragmentList!!, titleList!!,this)
    activity_tablayout.setupWithViewPager(activity_viewPager)

    for (i in 0..2) {
        val tab = activity_tablayout.getTabAt(i)
        //注意！！！这里就是添加我们自定义的布局
        tab!!.setCustomView(adapter!!.getCustomView(i))
        //这里是初始化时，默认item0被选中，setSelected（true）是为了给图片和文字设置选中效果，代码在文章最后贴出
        if (i == 0) {
            (tab!!.getCustomView()!!.findViewById(R.id.tab_iv) as ImageView).isSelected = true
            (tab!!.getCustomView()!!.findViewById(R.id.tab_tv) as TextView).isSelected = true
        }
    }

}

demo云盘链接：https://pan.baidu.com/s/1HJKbRY0WBXGMfwmU-AP7HA

密码在线回复:QQ1085220040

kotlin工程demo链接：https://download.csdn.net/download/meixi_android/11212091