Kotlin学习笔记——Fragment

#define 小毛驴 xml

使用方法

Fragment与ViewPager搭配，实现翻页，实现每页多个控件

1. 写好每个item的小毛驴文件和数据传送类
2. 继承Fragment类，自定义一个fragment

   class BlankFragment : Fragment() {
       var ctx:Context? = null
       var mPosition:Int = 0
       var mInageId:Int = 0
       var mDesc:String = ""
       var title:String = ""
   
       val colorNames = listOf<String>("红色","黄色","绿色","青色","蓝色")
       val colors = intArrayOf(Color.RED, Color.YELLOW, Color.GREEN, Color.CYAN, Color.BLUE)
       var mSeq:Int = 0
       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")
           }//获取数据
           val view = inflater.inflate(R.layout.show_info, container, false)
   
           view.findViewById<ImageView>(R.id.imageView).setImageResource(mInageId)
           view.findViewById<TextView>(R.id.textView).text = mDesc
           //显示数据
           return view
       }
   
       companion object {
           fun newInstance(position:Int, image_id:Int, desc:String, title:String) : BlankFragment {//调用这个函数，创建新的fragment
   
               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
           }
       }
   }

3. ViewPager的适配器

   class 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
       }
   }

   4.给ViewPager添加适配器

   class MainActivity : FragmentActivity(){
   //这个时候，继承的是FragmentActivity
       override fun onCreate(savedInstanceState: Bundle?) {
           super.onCreate(savedInstanceState)
           setContentView(R.layout.activity_main)
           var vp:ViewPager = findViewById(R.id.vp)
           var title: PagerTabStrip = findViewById(R.id.title)
           val list:MutableList<itemInfo> = mutableListOf()
           //省略中间给list赋值的过程
           vp.adapter = infoPagerAdapter(supportFragmentManager, list)
           vp.currentItem = 0
       }
   }