Recycleview的简单使用

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xml

activity_main.xml

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<RelativeLayout 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"
    tools:context="com.example.yangqiuyan.clickdemo.MainActivity">

    <Button
        android:id="@+id/add_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="add" />

    <Button
        android:id="@+id/remove_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/add_button"
        android:text="remove" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/my_recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/remove_button"
        android:scrollbars="vertical" />

</RelativeLayout>

MainActivity.java

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class MainActivity : AppCompatActivity() {

    var mMyAdapter: MyAdapter? = null
    var mLayoutManager: LinearLayoutManager? = null
    var mRecyclerView: RecyclerView? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        initData()
        initView()
        initListener()
    }

    fun initData() {
        mMyAdapter = MyAdapter(this, getData())
        mLayoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
    }

    fun initView() {
        mRecyclerView = findViewById(R.id.my_recyclerview)
        // 设置布局管理器
        mRecyclerView!!.layoutManager = mLayoutManager
        // 设置适配器
        mRecyclerView!!.adapter = mMyAdapter
        // 设置recycleview添加和移除动画
        mRecyclerView!!.itemAnimator = DefaultItemAnimator()
    }

    fun getData(): ArrayList<String> {
        var data = ArrayList<String>()
        (0 until 25).mapTo(data) { "item" + it }
        return data
    }

    fun initListener() {
        add_button.setOnClickListener {
            mMyAdapter!!.addNewItem()
        }
        remove_button.setOnClickListener {
            mMyAdapter!!.deleteitem()
        }
    }
}

MyAdapter.java

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class MyAdapter(context: Context, data: ArrayList<String>) : RecyclerView.Adapter<MyAdapter.ViewHolder>() {

    var context: Context? = null
    var data: ArrayList<String>? = null

    init {
        this.context = context
        this.data = data
    }

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
        var view = LayoutInflater.from(context).inflate(R.layout.recycleview_item, parent, false)
        var viewHolder = ViewHolder(view)
        return viewHolder
    }

    override fun getItemCount(): Int {
        return data!!.size
    }

    override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
        holder!!.textview!!.text = data!![position]
    }


    class ViewHolder(itemView: View?) : RecyclerView.ViewHolder(itemView) {
        var textview: TextView? = null

        init {
            textview = itemView?.findViewById(R.id.textview)
        }
    }

    fun addNewItem() {
        data!!.add(1, "new item")
        notifyItemInserted(1)
    }

    fun deleteitem() {
        data!!.removeAt(1)
        notifyItemRemoved(1)
    }
}

每个item的布局文件这里就不贴出来。

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