Kotlin 技术培训 - PDF Free Download

效率的抉择 : 用 Kotlin 做 Android 开发 Bennyhuo

个人简介霍丙乾,Bennyhuo, 就职于腾讯地图 Github: https://github.com/enbandari Kotlin 微信公众号 Kotlin 社区 :https://kotliner.cn Kotlin 博客 :https://blog.kotliner.cn

Kotlin 简介

Kotlin 的基本情况

Kotlin 的基本情况 Andrey Breslav Hadi Hariri

Kotlin 的基本情况

Kotlin 的基本情况 100% 兼容 Java

Kotlin 的基本情况

Kotlin 的基本情况 Android 官方开发语言

Kotlin 的基本情况

Kotlin 的基本情况正式支持 JavaScript Target

Kotlin 的基本情况

Kotlin 的基本情况 Native Target 预览版 0.4

Kotlin 的基本情况

你是如何认识 Kotlin 的? 其他 15% 同学朋友 8% 缘分 13% Google IO 大会 42% JetBrains 22%

你从事何种职业? 其他 13% 服务端研发 14% 学生 17% Android 研发 56%

你或者你所在的项目如何使用 Kotlin 的? 其他 2% 不敢用 16% 全部使用 Kotlin 17% Demo 开发 44% 小范围线上 21%

你觉得 Kotlin 最吸引你的特性是什么? 没有分号 5% 属性代理 3% DSL 4% 协程 4% 数据类型 10% Lambda/ 高阶函数 25% 空安全类型 18% 跨平台一统江湖 17% 扩展方法 14%

你所在的公司人数? 10000 以上 9% 1000-10000 12% 50 人以下 41% 200-1000 19% 50-200 19%

你的年龄范围? 85 后 17% 其他 1% 80 后 8% 00 后 2% 95 后 25% 90 后 47%

Kotlin 高端大气上档次

相关资料

Android developer 地址 : https://developer.android.com/kotlin/index.html

Kotlin 官网地址 : http://kotlinlang.org/

Kotlin 官网 ( 中文版 ) 地址 :https://www.kotlincn.net/

Kotlin 论坛地址 :https://discuss.kotlinlang.org/

Kotlin 论坛 ( 中文版 ) 地址 :https://kotliner.cn/

Kotlin 博客地址 :https://blog.jetbrains.com/kotlin

Kotlin 博客 ( 中文版 ) 地址 :https://blog.kotliner.cn/

Kotlin 公众号微信公众号 :Kotlin

Kotlin 教学视频 O'Reilly Introduction to Kotlin Programming:http://hadihariri.com/2016/11/01/oreillykotlin-course/ O'Reilly Advanced Kotlin Programming:http://hadihariri.com/2016/11/01/oreilly-kotlincourse/ Github Kotlin 入门到放弃 :https://github.com/enbandari/kotlin-tutorials 慕课网 Kotlin 入门到进阶 :http://coding.imooc.com/class/108.html

培训目标认识 Kotlin 了解 Kotlin 的基本语法熟悉 Kotlin 特性的一些应用场景最后把培训的内容都忘了

下面开始讲代码

Kotlin 版本 Jvm/Js 1.0 2016.2 1.1 2017 1.2 即将面世

简洁, 就要少写废话

高效, 就要少犯错误

创建工程

配置工程 buildscript { ext.kotlin_version = '1.1.51' repositories { google() jcenter() dependencies { classpath 'com.android.tools.build:gradle:3.0.0' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" // NOTE: Do not place your application dependencies here; they belong // in the individual module build.gradle files

配置工程 apply plugin: 'com.android.application' apply plugin: 'kotlin-android' android {... dependencies { implementation filetree(dir: 'libs', include: ['*.jar']) implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version...

如何定义变量 int anint = 2;

如何定义变量 val anint: Int = 2

如何定义变量 val anint = 2

如何定义变量 val anint = 2 anint = 3

如何定义变量 var anint = 2 anint = 3

如何定义变量 val anint = 2 final int anint = 2; var anint = 2 int anint = 2; Kotlin Java

如何定义函数 void hello(int anint){ System.out.println(anInt);

如何定义函数 fun hello(anint: Int): Unit{ println(anint)

如何定义函数 fun hello(anint: Int) { println(anint)

如何定义函数 fun hello(anint: Int): Unit{ println(anint)

如何定义数组 int[] intarray = new int[5]; int[] anotherintarray = {1,2, 3,4,5;

如何定义数组 val intarray = IntArray(5) val anotherintarray = intarrayof(1, 2, 3, 4, 5)

如何定义数组 int[] intarray = new int[5];

如何定义数组 int[] intarray = new int[5]; for (int i = 0; i < intarray.length; i++) { intarray[i] = i;

如何定义数组 val intarray = IntArray(5){ it

如何定义数组 val intarray = IntArray(5){ it * 2

如何操作数组 intarray[1] = 2; int element3 = intarray[3] ;

如何操作数组 intarray[1] = 2 val element3 = intarray[3]

运算符 intarray[1] = 2 intarray.set(1, 2) val element3 = intarray[3] val element3 = intarray.get(3) 如果是 List Set 呢?

运算符 class 逗你玩 { operator fun set(int: Int, value: Any){ operator fun get(int: Int) = Unit

运算符 class 逗你玩 { operator fun set(int: Int, value: Any){ operator fun get(int: Int) = Unit val 逗你玩的实例 = 逗你玩 () 逗你玩的实例 [2] = 3 val x = 逗你玩的实例 [1]

WARNING 请不要用中文编程, 不然你可能找不到工作

数组的类型基本类型的数组 ShortArray/IntArray/LongArray/FloatArray/DoubleArray/CharArray/Bool eanarray 其他类型数组 val stringarray = Array(5){ it.tostring() // Array<String> val anotherstringarray = arrayof("hello", "world") val strings = arrayofnulls<string>(5)

如何定义类 interface AnInterface{ class SuperClass{ public SuperClass() { class SubClass extends SuperClass implements AnInterface{ public SubClass() { super();

如何定义类 interface AnInterface class SuperClass(){ class SubClass : SuperClass(), AnInterface{

如何定义类 interface AnInterface class SuperClass{ class SubClass : SuperClass(), AnInterface{

如何定义类 interface AnInterface class SuperClass class SubClass : SuperClass(), AnInterface

如何定义类 interface AnInterface open class SuperClass class SubClass : SuperClass(), AnInterface

如何实例化类 SubClass subclass = new SubClass();

如何实例化类 val subclass = new SubClass()

如何实例化类 val subclass = SubClass()

如何实例化类 var subclass = SubClass()

构造方法 interface AnInterface open class SuperClass class SubClass : SuperClass(), AnInterface

构造方法 interface AnInterface open class SuperClass( aparam: Int ) class SubClass : SuperClass( 10 ), AnInterface

构造方法 interface AnInterface open class SuperClass(aParam: Int) { init { println(aparam) val aproperty = aparam class SubClass : SuperClass(10), AnInterface

构造方法 interface AnInterface open class SuperClass(aParam: Int) { init { println(aparam) val aproperty = aparam class SubClass ( aparamforsuper: Int ) : SuperClass( aparamforsuper ), AnInterface

构造方法 class SubClass( val apropertyinsub: String, aparamforsuper: Int ) : SuperClass( aparamforsuper ), AnInterface

构造方法 class SubClass( val apropertyinsub: String, aparamforsuper: Int ) : SuperClass( aparamforsuper ), AnInterface val subclass = SubClass("Hello", 10) subclass.

构造方法 public class Call { private String callid;

构造方法 public class Call { private String callid; public Call(String callid) { this.callid = callid;

构造方法 public class Call { private String callid; public Call(){ // 稍后再初始化 callid public Call(String callid) { this.callid = callid;

构造方法 public class Call { private final String callid; public Call(String callid) { this.callid = callid;

构造方法 class Call(val callid: String)

构造方法 class Call(val callid: String){ constructor()

构造方法 class Call(val callid: String){ constructor(): this()

构造方法 public ViewGroup(Context context) { this(context, null); public ViewGroup(Context context, AttributeSet attrs) { this(context, attrs, 0); public ViewGroup(Context context, AttributeSet attrs, int defstyleattr) { this(context, attrs, defstyleattr, 0); public ViewGroup(Context context, AttributeSet attrs, int defstyleattr, int defstyleres) { super(context, attrs, defstyleattr, defstyleres);...

构造方法 public SomeViewGroup(Context context) { super(context); init(); public SomeViewGroup(Context context, AttributeSet attrs) { super(context, attrs); init();

构造方法 public SomeViewGroup(Context context) { super(context); init(); initdata(); public SomeViewGroup(Context context, AttributeSet attrs) { super(context, attrs); init();

构造方法 public SomeViewGroup(Context context) { super(context); init(); initdata(); public SomeViewGroup(Context context, AttributeSet attrs) { super(context, attrs); init(); initdata();

方法重载 public interface List<E> extends Collection<E> {... public E remove(int location); public boolean remove(object object);...

方法重载 public interface List<E> extends Collection<E> {... public E remove(int location); public boolean remove(object object);... List<Integer> integers = new ArrayList<>();... integers.remove(2);

方法重载 public interface List<E> extends Collection<E> {... public E remove(int location); public boolean remove(object object);... val integers = ArrayList<Int>()... integers.removeat(2)

默认参数 class SomeViewGroup(context: Context, attrs: AttributeSet?, defstyleattr: Int, defstyleres: Int) : ViewGroup(context, attrs, defstyleattr, defstyleres) { init {...

默认参数 class SomeViewGroup(context: Context, attrs: AttributeSet? = null, defstyleattr: Int = 0, defstyleres: Int = 0) : ViewGroup(context, attrs, defstyleattr, defstyleres) { init {...

覆写父类成员 @Override protected void onresume() { super.onresume(); tencentmapview.onresume(); @Override protected void onpause() { super.onpause(); tencentmapview.onpause();

覆写父类成员 public class MyMapView extends MapView {... public void onresume() { dosomethingonresume(); @Override public void onpause() { super.onpause(); dosomethingonpause();...

覆写父类成员 class MyMapView(context: Context) : MapView(context) { fun onresume() { dosomethingonresume() override fun onpause() { super.onpause() dosomethingonpause()

覆写父类成员 class MyMapView(context: Context) : MapView(context) { override fun onresume() { dosomethingonresume() override fun onpause() { super.onpause() dosomethingonpause()

属性代理 public class Link { private double length = -1; private List<LatLng> points;...

属性代理 public void update(latlng latlng){... if(length == -1){ length = resolvelength();... private double resolvelength(){ return...;

属性代理 public void update(latlng latlng){... double length = getlength();... public double getlength(){ if(length == -1){ length = resolvelength(); return length; private double resolvelength(){ return...;

属性代理 private val length by lazy { resolvelength() private fun resolvelength(): Double { return...

属性代理 private val length by lazy {...

属性代理 private val length by lazy( SYNCHRONIZED ) {...

属性代理 enum class LazyThreadSafetyMode { SYNCHRONIZED, PUBLICATION, NONE,

属性代理 inline operator fun <T> Lazy<T>.getValue( thisref: Any?, property: KProperty<*> ): T = value

属性代理 private var _value: Any? = UNINITIALIZED_VALUE override val value: T get() { if (_value === UNINITIALIZED_VALUE) { _value = initializer!!() initializer = null return _value as T

属性代理 private var _value: Any? = UNINITIALIZED_VALUE override val value: T get() { if (_value === UNINITIALIZED_VALUE) { _value = initializer!!() initializer = null return _value as T private val length by lazy {...

属性代理 public interface ReadWriteProperty<in R, T> { public operator fun getvalue(thisref: R, property: KProperty<*>): T public operator fun setvalue(thisref: R, property: KProperty<*>, value: T)

属性代理 class PropertiesDelegate <T> (val path: String): ReadWriteProperty <Any, T> { val properties: Properties by lazy {... // 读属性 override operator fun getvalue(thisref: Any, property: KProperty<*>): T { val value = properties[property.name] val classoft = property.returntype.classifier as KClass<*> return if (Number::class.isSuperclassOf(classOfT)) {... // 如果是数值需要做一些转换 else { value as T override operator fun setvalue(thisref: Any, property: KProperty<*>, value: T) { properties[property.name] = value... // 存属性

属性代理 class PropertiesDelegate (val path: String) { val properties: Properties by lazy {... // 读属性 operator fun <T> getvalue(thisref: Any, property: KProperty<*>): T { val value = properties[property.name] val classoft = property.returntype.classifier as KClass<*> return if (Number::class.isSuperclassOf(classOfT)) {... // 如果是数值需要做一些转换 else { value as T operator fun <T> setvalue(thisref: Any, property: KProperty<*>, value: T) { properties[property.name] = value... // 存属性

属性代理 abstract class AbsProperties(path: String) { protected val prop = PropertiesDelegate(path)

属性代理 abstract class AbsProperties(path: String) { protected val prop = PropertiesDelegate(path) object MetaInfo: AbsProperties("/meta.properties"){ val version: String by prop val author: String by prop val name: String by prop val desc: String by prop

属性代理 object MetaInfo: AbsProperties("/meta.properties"){ val version: String by prop val author: String by prop val name: String by prop val desc: String by prop version=1.0-snapshot author=bennyhuo@kotliner.cn name=qcloudimageuploader desc= 方便地批量上传指定目录的图片到腾讯云的免费 50G 图床

属性代理 link: <https://api.github.com/user/repos?page=2>; rel="next", <https://api.github.com/user/repos?page=5>; rel="last"

属性代理 map["next"] = "https://api.github.com/user/repos?page=2" map["last"] = "https://api.github.com/user/repos?page=5"

属性代理 map["next"] = "https://api.github.com/user/repos?page=2" map["last"] = "https://api.github.com/user/repos?page=5" map["first"] = "https://api.github.com/user/repos?page=1" map["prev"] = "https://api.github.com/user/repos?page=1"

属性代理 class GitHubPaging{ val islast: Boolean =? val isfirst: Boolean =? val hasprev: Boolean =? val hasnext: Boolean =? operator fun get(key: String): String?{ return?

属性代理 class GitHubPaging{ val first: String? =? val last: String? =? val next: String? =? val prev: String? =? val islast: Boolean =? val isfirst: Boolean =? val hasprev: Boolean =? val hasnext: Boolean =?

属性代理 class GitHubPaging{ val first by map... val isfirst get() = first == null... 参考 Kotlin 公众号文章 : 用 Map 为你的属性做代理

属性代理 object Settings { var lastpage by pref(0) var daynightmode by pref(false) var enablepush by pref(false) 参考 Kotlin 公众号文章 : 用 Map 为你的属性做代理

接口代理 interface PageManager { fun showpage(clazz: KClass<out Page>) fun goback()

接口代理 class PageManagerImpl: PageManager{ override fun showpage(clazz: KClass<out Page>) {... override fun goback() {... override fun dismiss() {..

接口代理 abstract class AbstractPage(val pagemanager: PageManager) : Page, PageManager { override fun showpage(clazz: KClass<out Page>) { pagemanager.showpage(clazz) override fun goback() { pagemanager.goback() override fun dismiss() { pagemanager.dismiss()

接口代理 abstract class AbstractPage(val pagemanager: PageManager) : Page, PageManager by pagemanager{

接口代理 abstract class AbstractPage(val pagemanager: PageManager) : Page, PageManager by pagemanager

扩展成员 inline operator fun <T> Lazy<T>.getValue( thisref: Any?, property: KProperty<*> ): T = value

扩展成员 public class DensityUtil { /** * 根据手机的分辨率从 dp 的单位转成为 px( 像素 ) */ public static int dip2px(float dpvalue) { final float scale = ContextHolder.getInstance().getContext().getResources().getDisplayMetrics().density; return (int) (dpvalue * scale + 0.5f); /** * 根据手机的分辨率从 px( 像素 ) 的单位转成为 dp */ public static int px2dip(float pxvalue) { final float scale = ContextHolder.getInstance().getContext().getResources().getDisplayMetrics().density; return (int) (pxvalue / scale + 0.5f);

扩展成员 //returns dip(dp) dimension value in pixels fun Context.dip(value: Int): Int = (value * resources.displaymetrics.density).toint() fun Context.dip(value: Float): Int = (value * resources.displaymetrics.density).toint() //return sp dimension value in pixels fun Context.sp(value: Int): Int = (value * resources.displaymetrics.scaleddensity).toint() fun Context.sp(value: Float): Int = (value * resources.displaymetrics.scaleddensity).toint() //converts px value into dip or sp fun Context.px2dip(px: Int): Float = px.tofloat() / resources.displaymetrics.density fun Context.px2sp(px: Int): Float = px.tofloat() / resources.displaymetrics.scaleddensity

扩展成员 listview.scrollx = dip(2) paint.strokewidth = dip(2).tofloat() paint.textsize = sp(12).tofloat()

扩展成员 logger.error("*************************") logger.error("++++++++++++++++")

扩展成员 fun String.times(other: Int): String{ return (1..other).fold(StringBuilder()){ acc, i -> acc.append(this) acc.tostring()

扩展成员 logger.error("*************************") logger.error("++++++++++++++++")

扩展成员 logger.error("*".times(8) ) logger.error("+".times(8) )

扩展成员 fun String.times(other: Int): String{ return (1..other).fold(StringBuilder()){ acc, i -> acc.append(this) acc.tostring()

扩展成员 operator fun String.times(other: Int): String{ return (1..other).fold(StringBuilder()){ acc, i -> acc.append(this) acc.tostring()

扩展成员 logger.error("*".times(8) ) logger.error("+".times(8) )

扩展成员 logger.error("*" * 8 ) logger.error("+" * 8 )

运算符 a + b a - b a.plus(b) a.minus(b) a * b a / b a.times(b) a.div(b)

扩展成员 String formatteddate = new SimpleDateFormat("yyyy-MM-dd").format(new Date()); Java

扩展成员 new Date().format("yyyy-MM-dd") Groovy

扩展成员 val formatteddate = SimpleDateFormat("yyyy-MM-dd").format(Date()) Kotlin

扩展成员 fun Date.format(format: String) : String{ return SimpleDateFormat(format).format(this)

扩展成员 fun Date.format(format: String) : String = SimpleDateFormat(format).format(this)

扩展成员 fun Date.format(format: String) = SimpleDateFormat(format).format(this)

扩展成员 val formatteddate = SimpleDateFormat("yyyy-MM-dd").format(Date()) Kotlin

扩展成员 val formatteddate = Date().format("yyyy-MM-dd")

如何比较对象 String astring = "Hello Kotliner"; String anotherstring = new String("Hello Kotliner"); System.out.println(aString == anotherstring); System.out.println(aString.equals(anotherString)); System.out.println(aString == anotherstring.intern()); System.out.println(aString.equals(anotherString.intern()));

如何比较对象 val astring = "Hello Kotliner" val anotherstring = String("Hello Kotliner")

如何比较对象 val astring = "Hello Kotliner" val anotherstring = String("Hello Kotliner".toByteArray()) println(astring === anotherstring) println(astring == anotherstring) println(astring === anotherstring.intern()) println(astring == anotherstring.intern())

如何比较对象 val astring = "Hello Kotliner" val anotherstring = String("Hello Kotliner".toByteArray()) println(astring === anotherstring) println(astring.equals(anotherstring)) println(astring === anotherstring.intern()) println(astring.equals(anotherstring.intern()))

如何比较对象 a == b a.equals(b) a === b a == b Kotlin Java

如何比较对象 var anint =... var anotherint =... if(anint < anotherint){ println("anint < anotherint") else { println("anint > anotherint")

如何比较对象 var anint =... var anotherint =... if(anint.compareto( anotherint ) < 0){ println("anint < anotherint") else { println("anint > anotherint")

运算符 a == b a.equals(b) a < b a.compareto(b) < 0 a > b a.compareto(b) > 0 a >= b 和 a <= b 呢?

数据类 public class Link { private String id; private double length; private String name; private String attributes; public String getid() { return id; public void setid(string id) { this.id = id;... // Getters/Setters