之前個google定義kotlin為Android一級語言，小弟之前對kotlin也並不是很瞭解所以去了解之後寫了一份有關kotlin版的RecyclerView希望對新學習kotlin的人有一些幫助。

在使用kotlin之前我們要對在As中下載kotlin的外掛在重啟As之後新建一個Android專案在As的code欄最下面有一個convert Java file to kotlin file 轉換之後再Activity會有一個config的設定，它會幫你設定完kotlin在module的build.gradle和全域性build.gradle中設定kotlin的一系列配置

我們來看看我們的MainActivity頁面的操作

package com.example.liuqiang.kotlinforandroid

import android.app.Activity
import android.content.Context
import android.os.Bundle
import android.os.Handler
import android.os.Message
import android.support.v7.widget.LinearLayoutManager
import android.support.v7.widget.RecyclerView
import android.util.Log
import android.view.View
import android.widget.Button
import android.widget.Toast
import com.google.gson.*
import com.google.gson.reflect.TypeToken
import okhttp3.*
import java.io.IOException


class MainActivity : Activity() {
    //建立變數此處使用的網路訪問是基於okhttp的
    var mOkHttpClient: OkHttpClient? = null
    var request: Request? = null;
    var body: FormBody? = null;
    var btn_back: Button? = null;
    val context: Context = this
    var recyclerView: RecyclerView? = null;
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //載入資料
        loadData()
        //初始化控制元件和繫結事件
        btn_back = findViewById(R.id.btn_back) as Button;
        recyclerView = findViewById(R.id.recyclerView) as RecyclerView;
        btn_back!!.setOnClickListener {
            finish()
        }
    }

    fun loadData() {
        val path = "您的介面地址"
        //kotlin不需要new 可直接寫
        mOkHttpClient = OkHttpClient()
        //對應引數
        body = FormBody.Builder()
                .addEncoded("key", "val")
                .build()
        request = Request.Builder().url(path).post(body).build()
        //此處是重寫callback類也可以自己定義一個class類實現Callback
        mOkHttpClient!!.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call?, e: IOException?) {
            }

            override fun onResponse(call: Call?, response: Response?) {
                if (response != null) {
                    if (response.isSuccessful) {
                        //拿到伺服器返回引數
                        var response = response.body().string();
                        Log.d("###",response);
                        try {
                            //使用Gson解析返回資料
                            var gson: Gson = Gson()
                            var json: JsonParser= JsonParser();
                            var jent: JsonElement=json.parse(response) as JsonElement;
                            var job:JsonObject = jent.asJsonObject;
                            var jar: JsonArray;
                            jar = job.getAsJsonArray("rows");
                            //拿到gson類解析tyep
                            val turnsType = object : TypeToken<ArrayList<TestInfo>>() {}.type
                            val list: ArrayList<TestInfo>;
                            //完成解析
                            list = gson.fromJson<ArrayList<TestInfo>>(jar, turnsType);
                            //通知recyclerView
                            var message = Message();
                            message.obj = list;
                            hand.sendMessage(message);
                        } catch(e: Exception) {
                            println(e.message);
                        }

                    }
                }
            }

        });

    }
    //完成recyclerView適配
    var hand = object : Handler() {
        override fun handleMessage(msg: Message?) {
            super.handleMessage(msg)
            val list: ArrayList<TestInfo>;
            list = msg!!.obj as ArrayList<TestInfo>
            recyclerView!!.layoutManager = LinearLayoutManager(context);
            recyclerView!!.adapter = TestAdapter(list, context,itemClick());
        }
    }
    //inner關鍵字可以方位外部類的引數
    //次類是處理recyclerView的點選事件的
    inner class itemClick: ItemClick{
        override fun OnItemClick(v: View, position: Int) {
            Toast.makeText(context,"你點選了第"+(position+1)+"個",Toast.LENGTH_LONG).show();
        }
    }

}
 

package com.example.liuqiang.kotlinforandroid

import android.content.Context
import android.support.v7.widget.RecyclerView
import android.support.v7.widget.RecyclerView.Adapter
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import android.widget.Toast
import com.bumptech.glide.Glide
import com.example.liuqiang.kotlinforandroid.TestAdapter.MyHolder
import java.io.File

class TestAdapter : Adapter<MyHolder> {
    //定義引數
    var list: List<TestInfo>? = null;
    var contxt: Context? = null;
    //獲得事件回撥介面
    var item:ItemClick?=null;

    //初始化資料
    constructor(list: ArrayList<TestInfo>, contxt: Context,item:ItemClick) {
        this.list = list;
        this.contxt = contxt;
        this.item=item;
    }

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): MyHolder {
        //得到itemView
        var v: View = LayoutInflater.from(contxt).inflate(R.layout.item, null, false);
        var holder = MyHolder(v);
        //為itemView繫結點選事件
        v.setOnClickListener(onClick());
        return holder;
    }

    override fun getItemCount(): Int {
        var size = list!!.size
        return size;
    }

    override fun onBindViewHolder(holder: MyHolder?, position: Int) {
        var name = list!!.get(position).username;
        holder!!.txtName.setText(name);
        var dept = list!!.get(position).deptname;
        var path = "您的圖片地址;
        if(path.contains(".jpg")||path.contains(".png")){
            Glide.with(contxt)
                    .load(path)
                    .thumbnail(0.1f)//使用原圖的10/1作為略縮圖
                    .into(holder.image_head);
        }else{
            holder.image_head.setImageResource(R.drawable.mv);
        }
        //得到position防止滑動點選錯位
        holder.itemView.setTag(position);
        holder.bonus.setText(dept);

    }
    
    //viewHolder

    public class MyHolder(itemView: View?) : RecyclerView.ViewHolder(itemView) {
        var image_head: ImageView = itemView!!.findViewById(R.id.image_head) as ImageView;
        var txtName: TextView = itemView!!.findViewById(R.id.txtName) as TextView;
        var bonus: TextView = itemView!!.findViewById(R.id.bonus) as TextView;
    }

    //呼叫介面回撥
    inner class onClick:View.OnClickListener{
        override fun onClick(v: View?) {
            var positon:Int= v!!.getTag() as Int;
            if(item==null){
                Toast.makeText(contxt,"哈哈哈",Toast.LENGTH_LONG).show();
            }
            item!!.OnItemClick(v,positon);
        }

    }

}
 

package com.example.liuqiang.kotlinforandroid

import android.view.View

/**
 * Created by liuqiang on 2017/5/23.
 */
interface ItemClick {
    fun OnItemClick(v: View,position:Int);
}

package com.example.liuqiang.kotlinforandroid

import java.io.Serializable

/**
 * Created by liuqiang on 2017/5/21.
 */

//data 是資料類的關鍵字 預設給欄位配置get和set方法
data class TestInfo(var username:String, var fileContent:String,var deptname:String): Serializable{

}

package com.example.liuqiang.kotlinforandroid

import android.app.ProgressDialog
import android.content.Context

/**
 * Created by liuqiang on 2017/5/21.
 */
class Utils {
    var dialog:ProgressDialog?=null;
    fun showProgressDialog(context:Context,message:String,isFouse:Boolean){
        if(dialog==null){
            dialog=ProgressDialog(context);
        }
        dialog!!.setMessage(message);
        dialog!!.setCancelable(isFouse);
        dialog!!.setCanceledOnTouchOutside(isFouse);
        dialog!!.show();
    }

    fun cancelProgressDialog(){
        if(dialog!=null){
            dialog!!.dismiss();
            dialog=null;
        }
    }
}