kotlin笔记(4)

1. 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>(result, object : TypeToken>() {}.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>(result, object : TypeToken>() {}.type)
   
                    ThreadUtil.runOnUiThread(Runnable {
                        homeView.onLoadMoreSuccess(list)
                    })
   
   
                }
            })
        }
   
   
    }
   
   
    //回调view层
    override fun onLoadSuccess(list: List?) {
        //
        refreshLayout.isRefreshing = false
        homeAdapter.updateList(list)
    }
   
    override fun onLoadMoreSuccess(list: List?) {
        homeAdapter.loadMore(list)
    }
   

2. let表达式

    /**
     * 刷新数据
     */
    fun updateList(list: List?) {
   
       list?.let {
           this.list.clear()
           this.list.addAll(list)
           notifyDataSetChanged()
       }
   
        //this.list.clear()
        //this.list.addAll(list!!)
        //notifyDataSetChanged()
   
   
    }
   

3. 网络框架的封装

    1. 所有请求的基类
    class MRequest(val url:String,val responseHandler: ResponseHandler) {}
   
    2. 请求的回调
    interface ResponseHandler {
        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 sendRequest(req:MRequest){
   
            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(val url:String,val responseHandler: ResponseHandler) {
   
        /**
         * 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(result, type)
            return result
        }
   
        /**
         * 执行网络请求
         */
        fun excute(){
            //发送request
            NetManager.manager.sendRequest(this)
        }
    }
   

4. 在P层调用

    override fun loadMore(offset: Int) {
    //定义request
    val request = HomeRequest(offset,object : ResponseHandler>{
        override fun onError(msg: String?) {
            homeView.onError(msg)
        }
   
        override fun onSuccess(result: List) {
            homeView.onLoadMoreSuccess(result)
        }
    }).excute()
    
    //发送request
    //NetManager.manager.sendRequest(request)
   

   }