kotlin笔记(4)

MVP重构

 1. 创建presenter
 interface HomePresenter {
    
 }

 2. 创建presenter实现类
 /**
  * P层需要持有view层的引用
  * 注意: val homeView: HomeView 前面为什么要加val或者var  ,不加,只能在init中使用,在其他自己写的方法,无法调用
  */
 class HomePresenterImpl(val homeView: HomeView) : HomePresenter {
 }

 3. 在activity或者fragment使用
     //惰性加载
     val homePresenter by lazy { HomePresenterImpl(this) }

     //使用
     homePresenter.loadDatas()  //先生成抽象方法,然后在Impl类中实现该方法,网络请求成功后,再回调到view层
 完整代码:
 /**
  * P层需要持有view层的引用
  * 注意: val homeView: HomeView 前面为什么要加val或者var  ,不加,只能在init中使用,在其他自己写的方法,无法调用
  */
 class HomePresenterImpl(val homeView: HomeView) : HomePresenter {
     /**
      * 加载home界面数据或者刷新数据
      */
     override fun loadDatas() {
         val path = URLProviderUtils.getHomeUrl(0, 20)
         val request = Request.Builder()
                 .get()
                 .url(path)
                 .build()
         OkHttpClient().newCall(request).enqueue(object : Callback {
             override fun onFailure(call: Call?, e: IOException?) {
                 ThreadUtil.runOnUiThread(Runnable {
                     homeView.onError(e?.message)
                 })



             }

             override fun onResponse(call: Call?, response: Response?) {
 //                myToast("请求成功:" + Thread.currentThread().name)
                 val result = response?.body()?.string()
                 LogUtil.json(result, "请求成功:")

                 val gson = Gson()
                 val list = gson.fromJson<List<HomeItemBean>>(result, object : TypeToken<List<HomeItemBean>>() {}.type)

                 ThreadUtil.runOnUiThread(Runnable {
                     homeView.onLoadSuccess(list)
                 })


             }
         })
     }


     override fun loadMore(offset: Int) {
         val path = URLProviderUtils.getHomeUrl(offset, 20)
         val request = Request.Builder()
                 .get()
                 .url(path)
                 .build()
         OkHttpClient().newCall(request).enqueue(object : Callback {
             override fun onFailure(call: Call?, e: IOException?) {


                 ThreadUtil.runOnUiThread(Runnable {
                     homeView.onError(e?.message)
                 })



             }

             override fun onResponse(call: Call?, response: Response?) {

                 val result = response?.body()?.string()
                 LogUtil.json(result, "请求成功:")

                 val gson = Gson()
                 val list = gson.fromJson<List<HomeItemBean>>(result, object : TypeToken<List<HomeItemBean>>() {}.type)

                 ThreadUtil.runOnUiThread(Runnable {
                     homeView.onLoadMoreSuccess(list)
                 })


             }
         })
     }


 }


 //回调view层
 override fun onLoadSuccess(list: List<HomeItemBean>?) {
     //
     refreshLayout.isRefreshing = false
     homeAdapter.updateList(list)
 }

 override fun onLoadMoreSuccess(list: List<HomeItemBean>?) {
     homeAdapter.loadMore(list)
 }

let表达式

 /**
  * 刷新数据
  */
 fun updateList(list: List<HomeItemBean>?) {

    list?.let {
        this.list.clear()
        this.list.addAll(list)
        notifyDataSetChanged()
    }

     //this.list.clear()
     //this.list.addAll(list!!)
     //notifyDataSetChanged()


 }

网络框架的封装

 1. 所有请求的基类
 class MRequest<T>(val url:String,val responseHandler: ResponseHandler<T>) {}

 2. 请求的回调
 interface ResponseHandler<T> {
     fun onError(msg:String)
     fun onSuccess(result:T)
 }

 3. 发送网络请求的类
 /**
  *  发送网络请求的类
  */
 class NetManager private constructor(){

     val client by lazy { OkHttpClient() }

     companion object {
         val manager by lazy { NetManager() }
     }

     fun <T>sendRequest(req:MRequest<T>){

         val request = Request.Builder()
                 .get()
                 .url(req.url)
                 .build()
         client.newCall(request).enqueue(object : Callback {
             override fun onFailure(call: Call?, e: IOException?) {
                 ThreadUtil.runOnUiThread(Runnable {
                     req.responseHandler.onError(e?.message)
                 })



             }

             override fun onResponse(call: Call?, response: Response?) {
                 //myToast("请求成功:" + Thread.currentThread().name)
                 val result = response?.body()?.string()
                 LogUtil.json(result, "请求成功:")

                 //网络请求的解析
                 val parseResult = req.parseResult(result)

                 ThreadUtil.runOnUiThread(Runnable {
                     req.responseHandler.onSuccess(parseResult)
                 })


             }
         })
     }
 }

 //补充 网络请求的解析
 /**
  * 所有请求的基类
  */
 class MRequest<T>(val url:String,val responseHandler: ResponseHandler<T>) {

     /**
      * 解析网络请求的结果
      */
     fun parseResult(result: String?): T {
         val gson = Gson()

         //获取泛型类型
         val type = (this.javaClass.genericSuperclass as ParameterizedType).actualTypeArguments[0]
         val result = gson.fromJson<T>(result, type)
         return result
     }

     /**
      * 执行网络请求
      */
     fun excute(){
         //发送request
         NetManager.manager.sendRequest(this)
     }
 }

在P层调用

 override fun loadMore(offset: Int) {
 //定义request
 val request = HomeRequest(offset,object : ResponseHandler<List<HomeItemBean>>{
     override fun onError(msg: String?) {
         homeView.onError(msg)
     }

     override fun onSuccess(result: List<HomeItemBean>) {
         homeView.onLoadMoreSuccess(result)
     }
 }).excute()
 
 //发送request
 //NetManager.manager.sendRequest(request)

}