Kotlin学习笔记——TabLayout
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使用场景
如果想让ViewPager的tab标签和Toolbar合二为一的话，可以在Toolbar中嵌套TabLayout
使用方法
- 编写好小毛驴文件，把TabLayout嵌套到Toolbar中，编写好每一页的小毛驴布局文件，写好传递数据的类
- 编写Fragment
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38class BlankFragment : Fragment() {
var ctx:Context? = null
var mPosition:Int = 0
var mInageId:Int = 0
var mDesc:String = ""
var title:String = ""
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
ctx = activity
if (arguments != null) {
mPosition = arguments!!.getInt("position", 0)
mInageId = arguments!!.getInt("image_id", 0)
mDesc = arguments!!.getString("desc")
title = arguments!!.getString("title")
}
val view = inflater.inflate(R.layout.item, container, false)
val pic:ImageView = view.findViewById(R.id.imageView)
val desc:TextView = view.findViewById(R.id.textView)
pic.setImageResource(mInageId)
desc.text = mDesc
return view
}
companion object {
fun newInstance(position:Int, image_id:Int, desc:String, title:String) : BlankFragment {
val fragment = BlankFragment()
val bundle = Bundle()
bundle.putInt("position", position)
bundle.putInt("image_id", image_id)
bundle.putString("desc", desc)
bundle.putString("title", title)
fragment.arguments = bundle
return fragment
}
}
} - 编写ViewPager的适配器
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11class infoPagerAdapter(val fragManger: FragmentManager, val itemList:MutableList<itemInfo>) : FragmentStatePagerAdapter(fragManger) {
override fun getCount(): Int = itemList.size
override fun getItem(p0: Int): Fragment {
val item = itemList[p0]
return BlankFragment.newInstance(p0, item.pic, item.desc, item.name)
}
override fun getPageTitle(position: Int): CharSequence? {
return itemList[position].name
}
} - 给ViewPager添加适配器
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40class the_pics : AppCompatActivity() , TabLayout.OnTabSelectedListener {
override fun onTabReselected(p0: TabLayout.Tab?) {}
override fun onTabUnselected(p0: TabLayout.Tab?) {
}
override fun onTabSelected(p0: TabLayout.Tab?) {
if (p0 != null)
vp.currentItem = p0.position
//如果用户点击了某个标签，把下面ViewPager也滚动到相应位置
//以上三个重载函数都是Toolbar上的标签产生事件后相应的操作
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_the_pics)
val bar:android.support.v7.widget.Toolbar = findViewById(R.id.bar)
setSupportActionBar(bar)
supportActionBar?.title = ""
bar.setNavigationOnClickListener {
setResult(Activity.RESULT_OK)
finish()
}//设置Toolbar的返回导航键的click监听器
var data:MutableList<itemInfo> = mutableListOf()
/*省略data的赋值过程*/
tab_title.addOnTabSelectedListener(this)
vp.adapter = infoPagerAdapter(supportFragmentManager, data)
vp.addOnPageChangeListener(object : ViewPager.SimpleOnPageChangeListener() {
override fun onPageSelected(position: Int) {
tab_title.getTabAt(position)!!.select()//让标签栏的第position个变成被选择状态
//这个重载函数是ViewPager上有Page的改变后调用的函数
}
})
}
}