Android Studio 中用kotlin语言写出完整代码(包含布局文件和具体代码），实现以下功能： 1.创建数据库person.db和表info(id,name,phone) 2.点击”添加“按钮可以往数据库perso.db中表info中添加一条记录，其中用户名为张三+随机数字，电话为8855+随机数字。 3.点击”查询所有“按钮把表中的信息显示到RecyclerView列表中。

以下是使用Kotlin语言在Android Studio中实现该功能的完整代码，包括布局文件和具体代码：

布局文件 activity_main.xml：

<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=".MainActivity">

    <Button
        android:id="@+id/btn_add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="添加"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp"/>

    <Button
        android:id="@+id/btn_query_all"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="查询所有"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp"
        android:layout_toRightOf="@id/btn_add"/>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/btn_add"
        android:layout_marginTop="20dp"/>

</RelativeLayout>

数据模型类 Info.kt：

data class Info(val id: Int, val name: String, val phone: String)

数据库帮助类 DBHelper.kt：

class DBHelper(context: Context) : SQLiteOpenHelper(context, "person.db", null, 1) {

    override fun onCreate(db: SQLiteDatabase?) {
        db?.execSQL("create table info(_id integer primary key autoincrement, name text, phone text)")
    }

    override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {

    }
}

主界面代码 MainActivity.kt：

class MainActivity : AppCompatActivity() {

    private lateinit var dbHelper: DBHelper
    private lateinit var infoList: MutableList<Info>
    private lateinit var adapter: InfoAdapter
    private lateinit var recyclerView: RecyclerView

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

        dbHelper = DBHelper(this)

        findViewById<Button>(R.id.btn_add).setOnClickListener {
            val name = "张三${Random.nextInt(100)}"
            val phone = "8855${Random.nextInt(10000)}"
            val db = dbHelper.writableDatabase
            db.execSQL("insert into info(name, phone) values(?, ?)", arrayOf(name, phone))
            db.close()
            queryAll()
        }

        findViewById<Button>(R.id.btn_query_all).setOnClickListener {
            queryAll()
        }

        recyclerView = findViewById(R.id.recycler_view)
        val layoutManager = LinearLayoutManager(this)
        recyclerView.layoutManager = layoutManager
        infoList = mutableListOf()
        adapter = InfoAdapter(infoList)
        recyclerView.adapter = adapter
    }

    private fun queryAll() {
        val db = dbHelper.writableDatabase
        val cursor = db.query("info", null, null, null, null, null, null)
        infoList.clear()
        if (cursor.moveToFirst()) {
            do {
                val id = cursor.getInt(cursor.getColumnIndex("_id"))
                val name = cursor.getString(cursor.getColumnIndex("name"))
                val phone = cursor.getString(cursor.getColumnIndex("phone"))
                infoList.add(Info(id, name, phone))
            } while (cursor.moveToNext())
        }
        cursor.close()
        db.close()
        adapter.notifyDataSetChanged()
    }

    override fun onDestroy() {
        super.onDestroy()
        dbHelper.close()
    }
}

class InfoAdapter(val infoList: List<Info>) :
    RecyclerView.Adapter<InfoAdapter.ViewHolder>() {

    inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        val nameView: TextView = view.findViewById(R.id.name)
        val phoneView: TextView = view.findViewById(R.id.phone)
    }

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

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val info = infoList[position]
        holder.nameView.text = info.name
        holder.phoneView.text = info.phone
    }

    override fun getItemCount() = infoList.size
}

列表项布局文件 info_item.xml：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:padding="10dp">

    <TextView
        android:id="@+id/name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"/>

    <TextView
        android:id="@+id/phone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:layout_marginLeft="10dp"/>

</LinearLayout>