Kotlin 技术培训

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1 效率的抉择 : 用 Kotlin 做 Android 开发 Bennyhuo

2 个人简介霍丙乾,Bennyhuo, 就职于腾讯地图 Github: Kotlin 微信公众号 Kotlin 社区 : Kotlin 博客 :

3 Kotlin 简介

4 Kotlin 的基本情况

5 Kotlin 的基本情况

6 Kotlin 的基本情况 Andrey Breslav Hadi Hariri

7 Kotlin 的基本情况

8 Kotlin 的基本情况

9 Kotlin 的基本情况 100% 兼容 Java

10 Kotlin 的基本情况

11 Kotlin 的基本情况

12 Kotlin 的基本情况 Android 官方开发语言

13 Kotlin 的基本情况

14 Kotlin 的基本情况

15 Kotlin 的基本情况正式支持 JavaScript Target

16 Kotlin 的基本情况

17 Kotlin 的基本情况

18 Kotlin 的基本情况 Native Target 预览版 0.4

19 Kotlin 的基本情况

20 Kotlin 的基本情况

21 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%

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

23 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%

24 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%

25 你所在的公司人数? 以上 9% % 50 人以下 41% % %

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

27 Kotlin 高端大气上档次

28 相关资料

29 Android developer 地址 :

30 Kotlin 官网地址 :

31 Kotlin 官网 ( 中文版 ) 地址 :

32 Kotlin 论坛地址 :

33 Kotlin 论坛 ( 中文版 ) 地址 :

34 Kotlin 博客地址 :

35 Kotlin 博客 ( 中文版 ) 地址 :

36 Kotlin 公众号微信公众号 :Kotlin

37 Kotlin 教学视频 O'Reilly Introduction to Kotlin Programming: O'Reilly Advanced Kotlin Programming: Github Kotlin 入门到放弃 : 慕课网 Kotlin 入门到进阶 :

38 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

40 下面开始讲代码

41 Kotlin 版本 Jvm/Js 即将面世

42 简洁, 就要少写废话

43 高效, 就要少犯错误

44 创建工程

45 创建工程

46 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

$配置工程 buildscript { ext.kotlin_version = '1.1.51' repositories { google() jcenter() dependencies { classpath 'com.android.tools.build:gradle:3.0.0' classpath "org.$

47 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

48 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...

49 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...

50 如何定义变量 int anint = 2;

51 如何定义变量 val anint: Int = 2

52 如何定义变量 val anint: Int = 2

53 如何定义变量 val anint = 2

54 如何定义变量 val anint = 2 anint = 3

55 如何定义变量 val anint = 2 anint = 3

56 如何定义变量 var anint = 2 anint = 3

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

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

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

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

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

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

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

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

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

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

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

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

69 如何定义数组 int[] intarray = new int[5];

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

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

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

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

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

75 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?

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

77 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]

78 WARNING 请不要用中文编程, 不然你可能找不到工作

79 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)

80 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)

81 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)

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

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

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

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

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

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

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

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

90 如何实例化类 val subclass = new SubClass()

91 如何实例化类 val subclass = new SubClass()

92 如何实例化类 val subclass = SubClass()

93 如何实例化类 var subclass = SubClass()

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

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

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

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

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

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

100 构造方法 public class Call { private String callid;

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

102 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;

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

104 构造方法 class Call(val callid: String)

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

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

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

108 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);...

109

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

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

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

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

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

115 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);

116 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)

117 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)

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

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

120 protected void onresume() { super.onresume(); protected void onpause() { super.onpause(); tencentmapview.onpause();

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

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

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

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

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

126 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...;

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

128 属性代理 private val length by lazy {...

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

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

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

132 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

133 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 {...

134 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)

135 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

136 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

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

138 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

139 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 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

140 属性代理 link: < rel="next", < rel="last"

141 属性代理 link: < rel="next", < rel="last"

142 属性代理 map["next"] = " map["last"] = "

143 属性代理 map["next"] = " map["last"] = " map["first"] = " map["prev"] = "

144 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?

145 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 =?

146 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

147 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

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

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

150 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()

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

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

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

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

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

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

157 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);

158 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

177 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 String astring = "Hello Kotliner"; String anotherstring = new String("Hello Kotliner"); System.out.println(aString == anotherstring); System.out.println(aString.equals(anotherString)); System.

178 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()));

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

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

181 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())

182 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())

183 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())

184 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())

185 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()))

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

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

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

189 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?

190 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

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