#define 小毛驴 xml
布局管理器
LinearLayoutManager
类似于线性布局
| 构造 |
|---|
| (Context context) |
| (Context context,int orientation,boolean reverseLayout) |
| (Context context, AttributeSet attrs, int defStyleAttr,int defStyleRes) |
| 参数 | 解释 |
|---|---|
| Context context | 上下文，初始化时，构造方法内部加载资源用 |
| int orientation | 方向，垂直和水平，默认为垂直 |
| boolean reverseLayout | 是否倒序，设置为True，从最后一个item开始，倒序加载。此时，RecyclerView第一个item是添加进Adapter中的最后一个，最后一个item是第一个加进Adapter的数据,RecyclerView会自动滑到末尾 |
参考英勇青铜5
GridLayoutManager
类似GridView
| 构造 | 解释 |
|---|---|
| (Context context, int spanCount) | spanCount为列数 |
| (Context context, int spanCount, int orientation,boolean reverseLayout) | orientation在GridLayoutManager中有静态常量 |
StaggeredGridLayoutManager
瀑布流
| 构造 | 解释 |
|---|---|
| (int spanCount, int orientation) | 显然法 |
使用方法
- 写一个基础适配器
//abstract抽象类作为基类
abstract class RecyclerBaseAdapter<VH: RecyclerView.ViewHolder>(val context:Context)
: RecyclerView.Adapter<RecyclerView.ViewHolder>(), AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener {
//与小毛驴文件绑定
val inflater:LayoutInflater = LayoutInflater.from(context)
override abstract fun getItemCount(): Int
override abstract fun onCreateViewHolder(p0: ViewGroup, p1: Int): RecyclerView.ViewHolder
override fun getItemViewType(position: Int): Int = 0
override fun getItemId(position: Int): Long = position.toLong()
var itemClickListener:AdapterView.OnItemClickListener? = null
fun setOnItemClickListener(listener:AdapterView.OnItemClickListener) {
this.itemClickListener = listener
}
var itemLongClickListener: AdapterView.OnItemLongClickListener? = null
fun setOnItemLongClickLostenner(listener: AdapterView.OnItemLongClickListener) {
this.itemLongClickListener = listener
}
override fun onItemClick(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
}
override fun onItemLongClick(parent: AdapterView<*>?, view: View?, position: Int, id: Long): Boolean {
return true
}
}
- 设计好item的小毛驴文件，写好传送数据的类
- 完成业务逻辑的适配器
class RecyclerGridAdapter(context:Context, private val infos:MutableList<RecyclerInfo>) :
RecyclerBaseAdapter<RecyclerView.ViewHolder>(context) {
//继承刚才的基础类
override fun getItemCount(): Int = infos.size
override fun onCreateViewHolder(p0: ViewGroup, p1: Int): RecyclerView.ViewHolder {
val view: View = inflater.inflate(R.layout.layout ,p0, false)
return ItemHoder(view)
}
override fun onBindViewHolder(p0: RecyclerView.ViewHolder, p1: Int) {
val vh = p0 as ItemHoder
vh.pic.setImageResource(infos[p1].pic)
vh.text.text = infos[p1].text
}
inner class ItemHoder(view:View): RecyclerView.ViewHolder(view) {
val ll = view.findViewById<ConstraintLayout>(R.id.ll)
var pic = view.findViewById<ImageView>(R.id.pic)
var text = view.findViewById<TextView>(R.id.text)
}
}
- 为RecyclerView添加布局管理器和适配器
class MainActivity : AppCompatActivity() {
var l:RecyclerView? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var data:MutableList<RecyclerInfo> = mutableListOf()
//省略为data赋值的代码
l = findViewById(R.id.l)
l?.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
val adapter = RecyclerGridAdapter(this, data)
adapter.setOnItemClickListener(adapter)
adapter.setOnItemLongClickLostenner(adapter)
l?.adapter = adapter
l?.itemAnimator = DefaultItemAnimator()
l?.addItemDecoration(SpacesItemDecoration(30))
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menu?.add("LinearLayoutManager(线性)")
menu?.add("GridLayoutManager(网格)")
menu?.add("StaggeredGridLayoutManager(瀑布流)")
return super.onCreateOptionsMenu(menu)
}
override fun onOptionsItemSelected(item: MenuItem?): Boolean {
if (item != null) {//菜单中选择各种布局
when(item.title) {
"LinearLayoutManager(线性)" -> l?.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
"GridLayoutManager(网格)" -> l?.layoutManager = GridLayoutManager(this, 2)
"StaggeredGridLayoutManager(瀑布流)" -> l?.layoutManager = StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL)
else -> toast("error")
}
}
return super.onOptionsItemSelected(item)
}
}
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