Kotlin + Google mvp 实现新的架构模式

Posted 2022-11-22 yian_

转载请注明出处 ：http://blog.csdn.net/yianemail/article/details/53114630

一：介绍

Kotlin是由JetBrains设计的开放源码的编程语言，它正在Java开发者中变得越来越流行。Kotlin通常被吹捧为Java的继承者，相比较Java而言，Kotlin提供更为丰富的开发经验，因为它更现代，更具表现力和更简介。

如果你在寻求android开发的可替代编程语言，那么应该试一下Kotlin。使用Kotlin，你可以很容易的在Android工程中替代Java或者与Java混合使用。

本文接下来将介绍在Android Studio工程中如何使用Kotlin .

Kotlin ： https://kotlinlang.org/

二：Kotlin Studio 集成

app/build.gradle

apply plugin: 'com.android.application'
//add kotlin plugin
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'


android 
    compileSdkVersion 25
    buildToolsVersion "25.0.0"
    defaultConfig 
        applicationId "com.example.huanjulu.kotlinsource"
        minSdkVersion 21
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    
    buildTypes 
        //...
    
    sourceSets 
        main.java.srcDirs += 'src/main/kotlin'
    


dependencies 
    compile fileTree(dir: 'libs', include: ['*.jar'])

    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"



repositories 
    mavenCentral()

project/build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript 
    ext.kotlin_version = '1.0.5'
    repositories 
        jcenter()
    
    dependencies 
        classpath 'com.android.tools.build:gradle:2.2.2'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "org.jetbrains.kotlin:kotlin-android-extensions:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    


allprojects 
    repositories 
        jcenter()
    


task clean(type: Delete) 
    delete rootProject.buildDir

三：代码实例

MainActivity.kt

/**
 * Created by huanjulu on 16/11/9.
 */
class MainActivity : AppCompatActivity(), UserSessionContract.UserSessionView 

    var mPresenter: UserSessionContract.UserSessionPresenter? = null

    //Adapter
    var adapter: Adapter = Adapter(this)

    //实例化LinearLayoutManager
    var linearlayout = LinearLayoutManager(this)

    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        //start 订阅
        UserSessionPresenter(this).subscribe()

        mPresenter!!.dataP(null)

        //设置adapter 以及 layoutManager
        recycleview.adapter = adapter

        recycleview.layoutManager = linearlayout


    

    override fun onDestroy() 
        super.onDestroy()
        //cancle 订阅
        mPresenter!!.unSubscribe()
    


    override fun <T> dataV(t: T?) 

        t as List<String>

        //非空调用
        adapter!!.load(t)

    

    override fun setPresenter(p: UserSessionContract.UserSessionPresenter) 
        this.mPresenter = p
    

其中的remote data 模拟了一些网络数据

UserSessionRemoteImpl.kt

/**
 * Created by huanjulu on 16/11/9.
 */

class UserSessionRemoteImpl : UserSessionRemote 

    var data: List<UserSessionWrap> = listOf(UserSessionWrap(), UserSessionWrap(), UserSessionWrap(), UserSessionWrap(), UserSessionWrap(), UserSessionWrap())


    var datas: List<String> = listOf(
            "稀土攫金"
            , "泡在网上的日子",
            "cokk", "V2ex",
            "开发头条",
            "23code"

    )


    override fun <T> dataRemote(t: T?): List<String> 
        data.forEach 

        

        return datas

    

Adapter.kt

/**
 * Created by huanjulu on 16/11/9.
 */


class Adapter constructor(context: Context) : RecyclerView.Adapter<RecyclerView.ViewHolder>() 

    val mContext: Context?


    companion object 

    

    init 
        this.mContext = context
    


    val items = LinkedList<String>()


    override fun onBindViewHolder(holder: RecyclerView.ViewHolder?, position: Int) 
        (holder as ViewHolder).bind(items[position])

    

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

    fun load(articles: List<String>) 
        if (articles.isNotEmpty()) 
            items.run 
                clear()
                addAll(articles)
                notifyDataSetChanged()
            
        
    


    override fun getItemCount(): Int = items.size


    inner class ViewHolder(val view: View) : RecyclerView.ViewHolder(view) 


        fun bind(item: String) 

            view.run 
                tag = this
                Log.d("TAG", item)
                content.text = item
            

        
    

效果

四：结语

在使用完Kotlin之后，

• 干净整洁，代码量少了一半左右
• 类型推断，扩展方法
• when while if 表达式更加方便
• 和JAVA调用很方便，能直接使用原有的JAVA方法
• 是它可以配合ANKO（虽然ANKO现在还不支持JAVA8））,从此告别XML布局

代码下载 ：https://github.com/outparadox/KoltinDemo.git