我们一直用JAVA写代码，现在学了Kotlin，怎么用Kotlin怎么进行MVP抽取呢?

直接上代码!

各种base类

//BaseCallBack
abstract class BaseCallBack<T> : ClassCallBack<T>() {
    abstract fun onSuccess(t: T)
    abstract fun OnFail(error: String)
}

//BaseView
interface BaseView{}

//BasePresenter
interface BasePresenter{
    fun onAttch(baseview: BaseView)
}

Contrct策略类

interface MyContract {
    //P层接口
    interface IMyPresenter : BasePresenter {
        fun getData()
    }
    //M层接口
    interface IMyModel {
        fun <T> getData(url: String, baseCallBack: BaseCallBack<T>) {}
    }
    //V层接口
    interface IMyView : BaseView {
        fun <T> onSuccess(t: T) {}
        fun OnFail(error: String) {}
    }
}

api类

interface MyService {
    @GET
    fun get(@Url url:String): Flowable<ResponseBody>
}

重要类-----帮助获取实际泛型参数

abstract class ClassCallBack<T> {
    val classReal: Class<T>
        get() = getSuperClassGenericType(javaClass) as Class<T>

    private fun getSuperClassGenericType(clz: Class<*>): Class<*> {
        val type = clz.genericSuperclass as? ParameterizedType ?: return Any::class.java
        val params = type.actualTypeArguments
        return if (params[0] is ParameterizedType) {
            (params[0] as ParameterizedType).rawType as Class<*>
        } else
            try {
                params[0] as Class<*>
            } catch (O_O: Exception) {
                Any::class.java
            }
    }
}

Retrofit工具类以及INetwork

class RetrofitUtlis : INetWork {
    var myService: MyService

    //单例模式
    //1私有静态变量
    // 3静态方法获得本类对象
    //1和3合体
    companion object {
        private var mRetrofitUtlis: RetrofitUtlis? = null;

        //getInstance方法
        fun getInstance(): RetrofitUtlis? {
            if (mRetrofitUtlis == null) {
                synchronized(RetrofitUtlis::class) {
                    //反射
                    if (mRetrofitUtlis == null) {
                        mRetrofitUtlis = RetrofitUtlis()
                    }
                }
            }
            return mRetrofitUtlis
        }
    }

    //2私有无参构造
    private constructor() {
        //创建okhttp
        val okHttpClient = OkHttpClient()
            .newBuilder()
            .callTimeout(1000 * 10, TimeUnit.MILLISECONDS)
            .build()


        //创建retrofit
        //创建对象
        val retrofit = Retrofit.Builder()
            .client(okHttpClient)
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .baseUrl("https://www.wanandroid.com/")
            .build()

        //创建接口对象
        myService = retrofit.create(MyService::class.java)
        //调用接口方法

    }

    override fun <T> get(url: String, baseCallBack: BaseCallBack<T>) {
        val flowable = myService.get(url)

        flowable.subscribeOn(Schedulers.io())
            .onBackpressureBuffer()//设置被观察者的缓存策略--如果大于128个事件，则继续缓存
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(object : Subscriber<ResponseBody> {
                override fun onComplete() {
                }

                override fun onSubscribe(s: Subscription?) {
                    s!!.request(100)
                }

                override fun onNext(t: ResponseBody?) {
                    //成功
                    val json = t?.string()

                    val gson = Gson()
                    val o = gson.fromJson(json, baseCallBack.classReal)

                    baseCallBack.onSuccess(o)

                }

                override fun onError(t: Throwable?) {

                    baseCallBack.OnFail(t.toString())
                }

            });
    }

    override fun <T> get(url: String, map: Map<String, String>, callBack: BaseCallBack<T>) {}

    override fun <T> post(url: String, callBack: BaseCallBack<T>) {}

    override fun <T> post(url: String, map: Map<String, String>, callBack: BaseCallBack<T>) {}
}

interface INetWork{
    fun <T> get(url: String, baseCallBack: BaseCallBack<T>)

    fun <T> get(url: String, map: Map<String, String>, callBack: BaseCallBack<T>)
    fun <T> post(url: String, callBack: BaseCallBack<T>)
    fun <T> post(url: String, map: Map<String, String>, callBack: BaseCallBack<T>)
}

M层实现类

class MyModel : MyContract.IMyModel {
    override fun <T> getData(url: String, baseCallBack: BaseCallBack<T>) {
        RetrofitUtlis.getInstance()?.get(url, baseCallBack)
    }
}

P层实现类

class MyPresenter : MyContract.IMyPresenter {
    var myModel: MyContract.IMyModel
    lateinit var myView: MyContract.IMyView

    constructor() {
        myModel = MyModel()
    }

    override fun getData() {
        myModel.getData("https://www.wanandroid.com/project/list/1/json?cid=294", object : BaseCallBack<MyBean>() {
            override fun onSuccess(t: MyBean) {
                myView.onSuccess(t)
            }

            override fun OnFail(error: String) {
                myView.OnFail(error)
            }
        })
    }

    override fun onAttch(baseview: BaseView) {
        myView = baseview as MyContract.IMyView;
    }

}

---

那么kotlin写RecyclerView呢?

学习网址
主要是适配器方面

首先介绍一下单布局(以及对条目的监听)

class SAdapter(private val context: Context, private val list: ArrayList<DataX>?) :
    RecyclerView.Adapter<SAdapter.SimpleViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SAdapter.SimpleViewHolder {
        var view = LayoutInflater.from(context).inflate(R.layout.item_view, null)
        return SimpleViewHolder(view)
    }

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

    override fun onBindViewHolder(holder: SAdapter.SimpleViewHolder, position: Int) {
        holder.tv_re.setText(list!!.get(position).desc)

//对条目进行监听
   holder.tv_re.setOnClickListener {
            Toast.makeText(context, holder.tv_re.text, Toast.LENGTH_SHORT).show();
        }
    }


    inner class SimpleViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        var tv_re: TextView = view.findViewById(R.id.tv_re_item)
    }

}

接下来介绍一下多布局吧(包括条目点击和接口回调)

class SAdapter(private val context: Context, private val list: ArrayList<DataX>?) :
    RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    var myInterface: MyInterface? = null
    fun setListener(myInterface: MyInterface?) {
        this.myInterface = myInterface
    }


    private val VIEW_0 = 0
    private val VIEW_1 = 1
    private val VIEW_2 = 2

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        var view: View
        if (viewType == 0) {
            view = LayoutInflater.from(context).inflate(com.whx.kotlino.R.layout.item_view, null)
            return ViewHolder0(view)
        } else if (viewType == 1) {
            view = LayoutInflater.from(context).inflate(com.whx.kotlino.R.layout.item_view1, null)
            return ViewHolder1(view)
        } else {
            view = LayoutInflater.from(context).inflate(com.whx.kotlino.R.layout.item_view2, null)
            return ViewHolder2(view)
        }
    }

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

    override fun getItemViewType(position: Int): Int {
        if (position == VIEW_0) {
            return 0
        } else if (position == VIEW_1) {
            return 1
        } else {
            return 2
        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        val type = getItemViewType(position)
        if (type == 0) {
            if (holder is ViewHolder0) {
                holder.tv_re.setText(list!!.get(position).desc)
                holder.tv_re.setOnClickListener {
                    if (myInterface != null) {
                        myInterface!!.test(position)
                    }
                }
            }
        } else if (type == 1) {
            if (holder is ViewHolder1) {
                Glide.with(context).load("https://wanandroid.com/blogimgs/2baa4b4b-acfe-473c-b534-9d672423e564.png")
                    .into(holder.iv_view1)
            }
        } else {
            if (holder is ViewHolder2) {
                //设置图片加载器
                holder.banner_item2.setImageLoader(GlideImage())
                //加载网络图片
                val mImages = ArrayList<String>()
                mImages.add("https://wanandroid.com/blogimgs/2baa4b4b-acfe-473c-b534-9d672423e564.png")
                mImages.add("https://wanandroid.com/blogimgs/2baa4b4b-acfe-473c-b534-9d672423e564.png")
                mImages.add("https://wanandroid.com/blogimgs/2baa4b4b-acfe-473c-b534-9d672423e564.png")
                //设置图片集合
                holder.banner_item2.setImages(mImages)

                //banner设置方法全部调用完毕时最后调用
                holder.banner_item2.start()
            }

        }
    }

    inner class GlideImage : ImageLoader() {
        override fun displayImage(context: Context, path: Any, imageView: ImageView) {
            Glide.with(context).load(path).into(imageView)
        }
    }

    class ViewHolder0(view: View?) : RecyclerView.ViewHolder(view!!) {
        var tv_re: TextView = view!!.findViewById(com.whx.kotlino.R.id.tv_re_item)
    }

    class ViewHolder1(view: View?) : RecyclerView.ViewHolder(view!!) {
        var iv_view1: ImageView = view!!.findViewById(com.whx.kotlino.R.id.iv_view1)
    }

    class ViewHolder2(view: View?) : RecyclerView.ViewHolder(view!!) {
        var banner_item2: Banner = view!!.findViewById(com.whx.kotlino.R.id.banner_item2)
    }

    interface MyInterface {
        fun test(position: Int)
    }

}

接下来我们来谈一谈数据库吧！

参考网址
首先先配置

//GreenDao
//项目app依赖
implementation 'org.greenrobot:greendao:3.2.2' // add library
-------------------------
//工程依赖
 mavenCentral() // 添加的代码
 classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2' // add plugin
-------------------------
//项目依赖
apply plugin: 'org.greenrobot.greendao' // apply plugin
-------------------------
greendao{
        schemaVersion 1 //数据库版本号
        daoPackage 'com.example.exercise2.dao'  //数据库全路径
        targetGenDir 'src/main/java'  //存放位置
    }

然后创建一个bean类（用java类创建）

@Entity
public class MyDaoBean {
    //自增的ID
    @Id(autoincrement = true)
    long e_id;
    String name;
}

锤后自动生成三个类 路径是根据你上边 greendao 给的

接下来我们写工具类

class My private constructor(context: Context) {
    var myDaoDao: MyDaoBeanDao

    init {
        //第一种方法
        val devOpenHelper = DaoMaster.DevOpenHelper(context, "my", null)
        val writableDb = devOpenHelper.writableDb
        val daoMaster = DaoMaster(writableDb)
        val newSession = daoMaster.newSession()
        this.myDaoDao = newSession.myDaoBeanDao
        //第二种方法
//        val newDevSession = DaoMaster.newDevSession(context, "my")
//        val myDaoDao1 = newDevSession.myDaoDao
    }

    //伴生  ——   单例
    companion object {
        private var my: My? = null
        fun getmy(context: Context): My? {
            if (my == null) {
                @Synchronized
                if (my == null) {
                    my = My(context)
                }
            }
            return my
        }
    }


    //添加数据
    fun getinsert(myDao: MyDaoBean) {
        myDaoDao.insert(myDao)
    }

    //删除数据
    fun getdelet(myDao: MyDaoBean) {
        myDaoDao.delete(myDao)
    }

    //修改数据
    fun getupdata(myDao: MyDaoBean) {
        myDaoDao.update(myDao)
    }

    //查询数据(指定数据)
    fun getquest_count(name: String): List<MyDaoBean> {
        val where = myDaoDao.queryBuilder().where(MyDaoBeanDao.Properties.Name.eq(name)).list()
        return where
    }

    //查询数据(所有数据)
    fun getquest_true(name: String): List<MyDaoBean> {
        val list = myDaoDao.queryBuilder().list()
        return list
    }

    //查询数据(模糊数据)
    fun getquest_like(name: String): List<MyDaoBean> {
        val where = myDaoDao.queryBuilder().where(MyDaoBeanDao.Properties.Name.like("%$name%")).list()
        return where
    }
}

调用--添加数据

My.getmy(this)?.getinsert(myDaoBean)