Kotlin安卓开发指南

什么是Android在AndroidStudio中创建一个项目创建一个TheRecycler使Forecastlist可点击ForecastListAdapter的clicklistenerKotlinAndroid怎么去使用KotlinAndroid实现Flowcontrol和ranges提供一个新的访问SharedPreferences测试你的UnittestingInstrumentationtests如果你觉得Java7是一个过期的语言，并决定找一个更现代的语言代替。恭喜你！就如你知道的，虽然Java8已经发布了，它包含了很多设备过期、几乎没有人使用它们之前我们也不能使用Java8，所以恐什么是什么是\hAndroidStudio，官方的AndroidIDE，就是基于Intellij，作对Java开发者来说，Kotlin是非常直觉化的，并且非常容易学它与我们日常生活使用的IDE无需配置就能完全整合。Android它更加安全：Kotlin是空安全的，也就是说在我们编译时期就处它是函数式的：Kotlin是基于面向对象的语言。但是就如其他很它是高度互操作性的：你可以继续使用所有的你用Java写的代码我们通过我们通过Kotlin我们通过Kotlin得到什么易表现publicclassArtist{privatelongid;privateStringname;privateStringurl;privateStringpubliclonggetId(){returnid;publicvoidsetId(longid){this.id=id;publicStringgetName()return publicvoidsetName(Stringname)= publicStringgetUrl()return publicvoidsetUrl(Stringurl)this.url= publicStringgetMbid()return publicvoidsetMbid(Stringmbid)this.mbid= @OverridepublicStringtoString()return"Artist{""id="+id",name='"+name+'\''",url='"+url+'\''",mbid='"+mbid+'\'' 48.1.1.dataclassvarid:Long,varname:String,varurl:String,varmbid:

这里不能通过编译Artist不能是varnotNullArtist:Artist=//Artist可以是varartist:Artist?=无法编译artist可能是null，我们需要进行处理只要在artistnull时才会打印智能转换if(artist!=null){只有在确保artist不是null使用Elvis操作符来给定一个在是nullvalname=artist?.name?:funfunFragment.toast(message:CharSequence,duration:Int=Toast.LENGTH_SHORT){Toast.makeText(getActivity(),message,3.1.1.fragment.toast("Hello函数式支持1.1.view.setOnClickListener{toast("Helloworld!")AndroidAndroidAndroidAndroidStudioAndroid第一件事就是安装AndroidStudio。就如你知道的，AndroidAndroidStudio是\hIntellijIDEA的插件实现，IntellijIDEA\h转移到AndroidStudio是Android开发者一个重要的改变。首先，\hAndroidStudio了。Kotlin团队也创建了一个针对Eclipse的插\h安装安装Kotlin现。前往AndroidStudio的

Kotlin：这是一个基础的插件。它能让AndroidStudio懂得KotlinAndroidExtensions：Kotlin团队还为Android开发发布了另外一个有趣的插件。这个AndroidExtensions可以因为从Intellij15开始，插件是被默认安装了的，但是你的AndroidStudio可能并没有。所以你需要进入AndroidStudio\hBeginnersCourseinUdacity。我们可能会关注不同的事情，但在在AndroidStudio在AndroidStudio在AndroidStudioCreatenewCreatenew

WeatherWeather下一步，它会让你选择最小的API版本。我们选择API15，因为我们AddnoAddnoBlankBlank

配置配置配置配置 buildscriptbuildscriptext.support_version=ext.kotlin_version=ext.anko_version=repositoriesdependenciesclasspath classpath"org.jetbrains.kotlin:kotlin-gradle- 12.allprojectsrepositories 17.

supportsupport

AndroidExtensionsAndroidExtensionsapplyplugin:'com.android.application'applyplugin:'kotlin-android'applyplugin:'kotlin-android-extensions'android{dependenciescompile"com.android.support:appcompat-v7:$support_version"compile"org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"compile"org.jetbrains.anko:anko-common:$anko_version"buildscriptrepositories{dependenciesclasspath"org.jetbrains.kotlin:kotlin-android- 把把MainActivity转换成KotlinKotlinplugin包含了一个有趣的特性，它能把Java代码转成ConvertJavaConvertJavaFiletoKotlin

我们想再将编写一些代码来测试KotlinAndroidExtensions是否 1.1.import overrideoverridefunonCreate(savedInstanceState:Bundle?)message.text="Hello5. \h的新的内容。如果你有疑问或者想查看代码，请在KotlinforAndroidDevelopersrepository查看。每个章节只要修改了代\h classclass3.1.1.classPerson(name:String,surname: classclassPerson(name:String,surname:String) 5.

openopenclassAnimal(name:classPerson(name:String,surname:String): funfunonCreate(savedInstanceState:Bundle?)

funfunadd(x:Int,y:Int):Intreturnx+3.1.1.funadd(x:Int,y:Int):Int=x+funfunadd(x:Int,y:Int):Intreturnx+3.funfuntoast(message:String,length:Int=Toast.LENGTH_SHORT)Toast.makeText(this,message,3.toast("Hello",voidvoidtoast(Stringvoidvoidtoast(Stringmessage,intToast.makeText(this,message,6.funfunniceToast(message: tag:String=javaClass<MainActivity>length:Int=Toast.LENGTH_SHORT)Toast.makeText(this,"[$className]$message",5.toast("Hello",toast("Hello","MyTag",1.1.toast(message="Hello",length=上编写复杂的String。在上面的例子中，我使用了”[$className]$message”。如你所见，任何时候你使用一 符号就可以插入一个表达式。如果这个表达式有点复杂，你就需要使用一对大括号括起来：”Yournameis${}” 创建一个创建一个创建一个创建一个 dependenciesdependenciescompilefileTree(dir:'libs',include:5. \h valvalforecastList=findViewById(R.id.forecast_list)asforecastList.layoutManager=

符 创建了一个对象的实例TheRecyclerTheRecyclerTheRecyclerTheRecyclerAdapterTheRecycler\h \h\h\h \h\h

classclassForecastListAdapter(valitems:List<String>)overridefunonCreateViewHolder(parent:ViewGroup,viewType:Int):ViewHolder{returnoverridefunonBindViewHolder(holder:ViewHolder,position:Int){holder.textView.text=overridefungetItemCount():Int=classViewHolder(valtextView:TextView): privateprivatevalitems="Mon6/23-Sunny-"Tue6/24-Foggy-"Wed6/25-Cloudy-"Thurs6/26-Rainy-"Fri6/27-Foggy-"Sat6/28-TRAPPEDINWEATHERSTATION-"Sun6/29-Sunny-overridefunonCreate(savedInstanceState:Bundle?)valforecastList=findViewById(R.id.forecast_list)asforecastList.layoutManager=LinearLayoutManager(this)forecastList.adapter=ForecastListAdapter(items)使用一个函数listOf创建一个常量的List（很快我们就会讲到的immutable）。它接收一个任何类型的

（可变长的参数），

valvalvald:Double=valvalvali:Int=位运算也有一点不同。在Android中，我们经常在 ////intbitwiseOr=FLAG1|intbitwiseAnd=FLAG1&//valbitwiseOr=FLAG1orvalbitwiseAnd=FLAG1and

\h字面上可以写明具体的类型。这个不是必须的，但是一个通用的valvali=12//AnvaliHex0x0f一个十六进制的Intvall=3L//Avald=3.5//Avalf=3.5F//Avalvals=valcs[2这是一个字符迭代vals=for(cin7.

valvals="Example"//Avali=23//AnvalactionBar=supportActionBar//AnActionBarinanActivityvalvala:Any=valc:Context=publicpublicclassPersonprivateStringpublicStringgetName()return publicvoidsetName(Stringname)= 9.Personperson=newStringname=publicclassPerson{varname:String=""valperson=Person()="name"valname=publicpublicclasssPersonvarname:String=get()=field="Name: 7.

backingbackingbacking backing1.1.dataclassForecast(valdate:Date,valtemperature:Float,valdetails:String)hashCode()我们可以得到一个hash值，也是从属性中计算出copy()你可以拷贝一个对象，可以根据你的需要去修改里面的

valvalf1=Forecast(Date(),27.5f,"Shinyvalf2=f1.copy(temperature= 些情况下，我们仍然可以修改这些状态。在上一个例子中，你还是可以访 另外一个方法是封装这些类。你可以创建一 类，它封 并且不允许去修改它们的状态。决定哪种方式取决于你。本书中，我不会 valvalf1=Forecast(Date(),27.5f,"Shinyval(date,temperature,details)=valvaldate=valtemperature=valdetails=

forfor((key,value)inmap)Log.d("map","key:$key,3.

a+a-a*a/a%aina!ina+=a-=a*=a/=a%=a[i,a.get(i,a[i_1,…,a.get(i_1,…,a[i]=a.set(i,a[i,j]=a.set(i,j,a[i_1,…,i_n]=a.set(i_1,…,i_n,a==a?.equals(b)?:b===a!=!(a?.equals(b)?:b===1.1.operatorfunequals(other:Any?):

a(i,a.invoke(i,a(i_1,…,a.invoke(i_1,…,valvalx=myList[2]= datadataclassForecastList(valcity:String,valcountry:valdailyForecast:List<Forecast>) operatorfunget(position:Int):Forecast=funsize():Int=5. overrideoverridefunonBindViewHolder(holder:position:Int)with(weekForecast[position])holder.textView.text="$date-$description- 6. 1.1.overridefungetItemCount():Int= 1.1.operatorfunViewGroup.get(position:Int):View=

valvalcontainer:ViewGroup=valview=别忘了去\hKotlinforAndroiddevelopersrepository去查看使使Forecastlist使Forecastlist使Forecastlist可点击使Forecastlist <?xmlversion="1.0"encoding="utf-\h\htools:text="May14,tools:text="LightdatadataclassForecast(valdate:String,valdescription: valhigh:Int,vallow:Int,valiconUrl: privatefunconvertForecastItemToDomain(forecast:Forecast):ModelForecast{returnModelForecast(convertDate(forecast.dt),privatefungenerateIconUrl(iconCode:String):=\h\h \h 1.1.compilepublicpublicinterfaceOnItemClickListeneroperatorfuninvoke(forecast:3. classViewHolder(view:View,valitemClick:OnItemClickListener)RecyclerView.ViewHolder(view)privatevaliconView:privatevaldateView:privatevaldescriptionView:privatevalmaxTemperatureView:privatevalminTemperatureView:initiconView=dateView=descriptionView=maxTemperatureView=minTemperatureView= funbindForecast(forecast:Forecast)with(forecast)dateView.text=descriptionView.text=maxTemperatureView.text=minTemperatureView.text=itemView.setOnClickListener{itemClick(forecast) 27.

publicclassForecastListAdapter(valweekForecast:valitemClick:ForecastListAdapter.OnItemClickListener) overridefunonCreateViewHolder(parent:ViewGroup,viewType:ViewHoldervalview=.inflate(R.layout.item_forecast,parent,returnViewHolder(view, overridefunonBindViewHolder(holder:ViewHolder,position:Int){ 16.

valvalView.ctx:get()= forecastListforecastList.adapter=object:overridefuninvoke(forecast:Forecast) Lambdas简化简化简化简化 publicpublicinterfaceOnClickListenervoidonClick(View3.viewview.setOnClickListener(newpublicvoidonClick(Viewv) Toast.makeText(v.getContext(),"Click", 6.viewview.setOnClickListener(object:OnClickListeneroverridefunonClick(v:View) 5.1.1.funsetOnClickListener(listener:(View)->1.1.view.setOnClickListener({view->1.1.view.setOnClickListener({toast("Click")1.1.view.setOnClickListener(){toast("Click")1.1.view.setOnClickListener{toast("Click")ForecastListAdapterForecastListAdapter的clickForecastListAdapter的click在前面一章，我这么艰苦地写了clicklistener的目的就是更好的publicpublicclassForecastListAdapter(valweekForecast:valitemClick:(Forecast)-> 1.1.classViewHolder(view:View,valitemClick:(Forecast)-> 1.1.valadapter=ForecastListAdapter(result){forecast->toast(forecast.date)} 1.1.valadapter=ForecastListAdapter(result){toast(it.date) 1.1.inlinefun<T>with(t:T,body:T.()->Unit){t.body()

withwith(forecast)dateView.text=descriptionView.text=maxTemperatureView.text=minTemperatureView.text=itemView.setOnClickListener{itemClick(this)8. inlineinlinefunsupportsLollipop(code:()->Unit)if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.LOLLIPOP) 5.supportsLollipopsupportsLollipop3.\h\h\hKotlin\h\h\h\h\hKotlin\h\h\h\h privateprotectedinternalpublic

根据Jetbrains的定义，一个module应该是一个单独的功能性的单位，它应该是可Studio中创建不同的module。在Eclipse中，这 可以认为是在 中的不同的project

1.1.classCprivateconstructor(a:Int){...

1.1.classRequestForecastCommand(privatevalzipCode: datadataclassForecastList(...)funget(position:Int)=funsize()=4.KotlinKotlinAndroidKotlinAndroidKotlinAndroidExtensionsKotlinAndroidKotlinKotlinKotlinAndroidKotlinAndroid

怎么去使用怎么去使用KotlinAndroid怎么去使用KotlinAndroid怎么去使用KotlinAndroidExtensionsAndroid AndroidAndroidAndroid怎么去使用KotlinAndroid如果你还记得，现在项目已经准备好去使用KotlinAndroid repositories dependencies classpath"org.jetbrains.kotlin:kotlin-android- 8. Android或 Android

1.1.import importimportimportAndroidAndroid 1.1.import1.1.view.textView.text=

KotlinAndroidKotlinAndroid 1.1.import \h overrideoverridefunonCreate(savedInstanceState:Bundle?)forecastList.layoutManager=LinearLayoutManager(this)

1.1.import

classclassViewHolder(view:View,valitemClick:(Forecast)->Unit)RecyclerView.ViewHolder(view)funbindForecast(forecast:Forecast)itemView.date.text=itemView.description.text=itemView.maxTemperature.text=itemView.minTemperature.text=itemView.onClick{itemClick(forecast) 13.KotlinAndroidExtensions插件帮助我们减少了很多模版代码，ApplicationApplication单例化和属性的个更简单的访问applicationcontext的方式。ApplicatonApplicatonclassclassApp:Application()companionobjectprivatevarinstance:Application?=funinstance()= overridefunonCreate()instance= 10.

classDelegate<T>:ReadWriteProperty<Any?,T>fungetValue(thisRef:Any?,property:KProperty<*>):T{return...funsetValue(thisRef:Any?,property:KProperty<*>,value:T) classclassExamplevarp:Stringby3.3. LazyObservableVetoableNotNull

值。这是非常有趣的特性，当我们在它们第一次真正调用之前不是必classApp:Application()valdatabase:SQLiteOpenHelperbylazy{overridefunonCreate(){valdb= lazy(LazyThreadSafeMode.NONE){...lazy(LazyThreadSafeMode.NONE){... 1.class1.classViewModel(valdb:MyDatabase)myPropertybyDelegates.observable("")d,old,new-db.saveChanges(this,6.

varvarpositiveNumber=Delegates.vetoable(0)d,old,new-new>=4.Not classApp:Application(){companionobject{varinstance:AppbyoverridefunonCreate(){instance=this10.10. importimportclassConfiguration(map:Map<String,Any?>)width:Intbyheight:Intbydp:IntbydeviceName:Stringby8.confconf="width"to"height"to"dp"to"deviceName"to

privateclassprivateclassNotNullSingleValueVar<T>():ReadWriteProperty<Any?,T>{ overridefungetValue(thisRef:Any?,property:KProperty<*>):T{throw overridefunsetValue(thisRef:Any?,property:KProperty<*>,value:T){GetterprivateclassprivateclassNotNullSingleValueVar<T>():ReadWriteProperty<Any?,T>{privatevarvalue:T?=overridefungetValue(thisRef:Any?,property:KProperty<*>):returnvalue?:throwIllegalStateException("${}"not overridefunsetValue(thisRef:Any?,property:KProperty<*>,value:T){this.value=if(this.value==null)elsethrowIllegalStateException("${}alreadyobjectobjectDelegatesExtfunReadWriteProperty<Any?,T>=4.重新实现重新实现Application classApp:Application(){companionobject{varinstance:AppbyoverridefunonCreate()instance=this companioncompanionobjectvarinstance:Appby3.创建一个创建一个创建一个创建一个 ManagedSqliteOpenHelper

forecastDbHelperforecastDbHelper.use3. publicfunpublicfun<T>use(f:SQLiteDatabase.()->T):Ttryreturnfinally7.

valvalresult=forecastDbHelper.usevalqueriedObject=4.

objectobjectCityForecastTablevalNAME=valID=valCITY=valCOUNTRY=6.objectobjectDayForecastTablevalNAME=valID=valDATE=

DESCRIPTION=HIGH=LOW=ICON_URL=CITY_ID=10.实现实现实现实现

classclassForecastDbHelper(): ForecastDbHelper.DB_NAME,null,ForecastDbHelper.DB_VERSION){4.

companion companioncompanioncompanionobjectvalDB_NAME=valDB_VERSION=valinstance:ForecastDbHelperbylazy{ForecastDbHelper()5.

CREATE CREATE Pair(CityForecastTable.ID,INTEGER+Pair(CityForecastTable.CITY,Pair(CityForecastTable.COUNTRY,

funfunSqlType.plus(m:SqlTypeModifier):SqlTypereturnSqlTypeImpl(name,if(modifier==null)else"$modifier4. 1.1.publicfun<A,B>A.to(that:B):Pair<A,B>=Pair(this,1.1.valpair=object1toCityForecastTable.IDtoINTEGER+CityForecastTable.CITYtoCityForecastTable.COUNTRYtooverrideoverridefunonCreate(db:SQLiteDatabase)CityForecastTable.IDtoINTEGER+CityForecastTable.CITYtoCityForecastTable.COUNTRYtodb.createTable(DayForecastTable.NAME,true,DayForecastTable.IDtoINTEGER+PRIMARY_KEY+DayForecastTable.DATEtoINTEGER,DayForecastTable.DESCRIPTIONtoTEXT,DayForecastTable.HIGHtoINTEGER,DayForecastTable.LOWtoINTEGER,DayForecastTable.ICON_URLtoTEXT,DayForecastTable.CITY_IDtoINTEGER)

overrideoverridefunonUpgrade(db:SQLiteDatabase,oldVersion:Int,newVersion:Int){5.\h\h

classclassForecastDbHelper(ctx:Context=App.instance) ManagedSQLiteOpenHelper(ctx,ForecastDbHelper.DB_NAME,ForecastDbHelper.DB_VERSION)valvaldbHelper1ForecastDbHelper它会使用valdbHelper2ForecastDbHelper(mockedContextCollection：这个类相是一个范性集合。我们通过函数访问可以

MutableList：一个支持增加和删除item的List。Set：一个无序并不支持重复item的集合。Map：一个key-value对的collection。key在map中是唯一anyallcountfoldfoldRightforEachforEachIndexedmaxmaxByminminBynonereducereduceRightsumByvalvallist=listOf(1,2,3,4,5,assertTrue(list.any{it%2==0assertFalse(list.any{it>10assertTrueassertTrue(list.all{it<10assertFalse(list.all{it%2==01.1.assertEquals(3,list.count{it%2==01.1.assertEquals(25,list.fold(4){total,next->total+next 1.1.assertEquals(25,list.foldRight(4){total,next->total+next1.1.list.forEach{println(it) listlist.forEachIndexed{index,->println("position$indexcontainsa$value")1.1.assertEquals(6,////TheelementwhosenegativeisassertEquals(1,list.maxBy{-it1.1.assertEquals(1,////TheelementwhosenegativeisassertEquals(6,list.minBy{-it1.1.//Noelementsaredivisibleby2.2.assertTrue(list.none{it%7==0 1.1.assertEquals(21,list.reduce{total,next->total+next 1.1.assertEquals(21,list.reduceRight{total,next->total+next1.1.assertEquals(3,list.sumBy{it%2dropdropWhiledropLastWhilefilterfilterNotfilterNotNullslicetaketakeLasttakeWhile1.1.assertEquals(listOf(5,6),1.1.assertEquals(listOf(3,4,5,6),list.dropWhile{it<31.1.assertEquals(listOf(1,2,3,4),list.dropLastWhile{it>41.1.assertEquals(listOf(2,4,6),list.filter{it%2==01.1.assertEquals(listOf(1,3,5),list.filterNot{it%2==01.1.assertEquals(listOf(1,2,3,4),1.1.assertEquals(listOf(2,4,5),list.slice(listOf(1,3,1.1.assertEquals(listOf(1,2),1.1.assertEquals(listOf(5,6),1.1.assertEquals(listOf(1,2),list.takeWhile{it<3flatMapgroupBymapmapIndexedmapNotNullassertEqualsassertEquals(listOf(1,2,2,3,3,4,4,5,5,6,6,list.flatMap{listOf(it,it+1)1.1.assertEquals(mapOf("odd"tolistOf(1,3,5),"even"tolistOf(2,4,6)),list.groupBy{if(it%2==0)"even"else"odd"})1.1.assertEquals(listOf(2,4,6,8,10,12),list.map{it*21.1.assertEquals(listOf(0,2,6,12,20,30),list.mapIndexed{index,it->index*it})1.1.assertEquals(listOf(2,4,6,8),listWithNull.mapNotNull{it*containselementAtelementAtOrElseelementAtOrNullfirstfirstOrNullindexOfindexOfFirstindexOfLastlastlastIndexOflastOrNullsinglesingleOrNull1.1. 1.1.assertEquals(2,1.1.assertEquals(20,list.elementAtOrElse(10,{2*it1.1.1.1.assertEquals(2,list.first{it%2==01.1.assertNull(list.firstOrNull{it%7==0 1.1.assertEquals(3, 1.1.assertEquals(1,list.indexOfFirst{it%2==0 1.1.assertEquals(5,list.indexOfLast{it%2==01.1.assertEquals(6,list.last{it%2==0 valvallist=listOf(1,2,3,4,5,assertNull(list.lastOrNull{it%7==01.1.assertEquals(5,list.single{it%5==01.1.assertNull(list.singleOrNull{it%7==0mergepartitionpluszipunzipvalvallist=listOf(1,2,3,4,5,vallistRepeated=listOf(2,2,3,4,5,5,assertEquals(listOf(3,4,6,8,10,11),list.merge(listRepeated){it1,it2->it1+it2})

Pair(listOf(2,4,6),listOf(1,3,list.partition{it%2==04. listOf(1,2,3,4,5,6,7,list+listOf(7,4.

listOf(Pair(1,7),Pair(2,list.zip(listOf(7,4.Pair(listOf(5,6),listOf(7,listOf(Pair(5,7),Pair(6,4.reversesortsortBysortDescendingsortDescendingByvalvalunsortedList=listOf(3,2,7,assertEquals(listOf(5,7,2,3),1.1.assertEquals(listOf(2,3,5,7),1.1.assertEquals(listOf(3,7,2,5),unsortedList.sortBy{it%31.1.assertEquals(listOf(7,5,3,2),1.1.assertEquals(listOf(2,5,7,3),unsortedList.sortDescendingBy{%3 创建数据库创建数据库model this._id=this.city=this.country=14.classCityForecast(valmap:MutableMap<String,valdailyForecast:List<DayForecast>)var_id:Longbymapvarcity:Stringbymapvarcountry:Stringbyconstructor(id:Long,city:String,country:String,dailyForecast:List<DayForecast>):this(HashMap(),dailyForecast)classclassDayForecast(varmap:MutableMap<String,Any?>)var_id:Longbyvardate:Longbyvardescription:Stringbyvarhigh:Intbyvarlow:IntbyvariconUrl:StringbyvarcityId:Longbyconstructor(date:Long,description:String,high:Int,low:iconUrl:String,cityId::this(HashMap()){this.date=datethis.description=descriptionthis.high=highthis.low=lowthis.iconUrl=iconUrlthis.cityId=cityId查询一个forecastdomaindomain

classclass valforecastDbHelper:ForecastDbHelper=valdataMapper:DbDataMapper=DbDataMapper())5.

funrequestForecastByZipCodefunrequestForecastByZipCode(zipCode:Long,date:Long)=forecastDbHelper.use{3.

查询一个 valvaldailyRequest="${DayForecastTable.CITY_ID}=?""AND${DayForecastTable.DATE}>=valdailyForecast=.whereSimple(dailyRequest,zipCode.toString(),.parseList{DayForecast(HashMap(it))

valvaldailyRequest="${DayForecastTable.CITY_ID}={id}"+${DayForecastTable.DATE}>=valdailyForecast=.where(dailyRequest,"id"tozipCode,"date"to.parseList{DayForecast(HashMap(it))

funfun<T:Any>parser:(Map<String,Any>)->T):List<T>parseList(object:MapRowParser<T> overridefunparseRow(columns:Map<String,Any>):T=5. 1.1.parseList{DayForecast(HashMap(it))databasedatabase

immutablemutableimmutablemutable

valvalcity= .whereSimple("${CityForecastTable.ID}=?",.parseOpt{CityForecast(HashMap(it),dailyForecast) publicpublicfun<T:Any>parser:(Map<String,Any>)->T):T?parseOpt(object:MapRowParser<T> overridefunparseRow(columns:Map<String,Any>):T= domain domain 1.1.if(city!=null)dataMapper.convertToDomain(city)elsefunfunconvertToDomain(forecast:CityForecast)=with(forecast)valdaily=dailyForecast.map{convertDayToDomain(it)ForecastList(_id,city,country,4.privatefunconvertDayToDomain(dayForecast:DayForecast)=with(dayForecast){Forecast(date,description,high,low,8.8.funrequestForecastByZipCodefunrequestForecastByZipCode(zipCode:Long,date:Long)=forecastDbHelper.use{valdailyRequest="${DayForecastTable.CITY_ID}=?AND""${DayForecastTable.DATE}>=valdailyForecast= .whereSimple(dailyRequest,zipCode.toString(),.parseList{DayForecast(HashMap(it))valcity=.whereSimple("${CityForecastTable.ID}=?",.parseOpt{CityForecast(HashMap(it),dailyForecast)if(city!=null)dataMapper.convertToDomain(city)else

保存一个

funfunsaveForecast(forecast:ForecastList)=forecastDbHelper.use3.

domaindomainfunfunSQLiteDatabase.clear(tableName:String)execSQL("deletefrom3. 3. funfunconvertFromDomain(forecast:ForecastList)=with(forecast)valdaily=dailyForecast.map{convertDayFromDomain(id,it)CityForecast(id,city,country,4.privatefunconvertDayFromDomain(cityId:Long,forecast:with(forecast)DayForecast(date,description,high,low,iconUrl,

Pair<String,Pair<String,

转换成AndroidSDK

1.1.fun<K,V:Any>MutableMap<K,Array<outPair<K,V>>map({Pair(it.key, mapmap

1.insert(CityForecastTable.1.insert(CityForecastTable.NAME,

1.1.dailyForecast.forEach{*it.map.toVarargArray()) funsaveForecast(forecast:ForecastList)=forecastDbHelper.use{with(dataMapper.convertFromDomain(forecast)){insert(CityForecastTable.NAME,*map.toVarargArray())dailyForecastforEach{insert(DayForecastTable.NAME,KotlinKotlin中的null如果你正在使用Java7工作的话，null安全是Kotlin中最令人感兴\hForecastForecastforecast= 可可null1.1.vala:Int?=valvala:Int?=5.

valorvalorvalvala:Int?= 至可以使用Elvis valvala:Int?=valmyString=a?.toString()?:

valvalmyString=a?.toString()?:returnvalmyString=a?.toString()?:throw valvala:Int?= 可可null性和JavaJava库和AndroidSDK会发生什么呢？在Java中，所有对象可以被

\h\h

\h\h\h \h\h \himportpublicclassNullTestpublicObjectgetObject(){return"";valvaltest=valmyObject:Any= 注解的方式和一些AndrodSDK的知识，我们也很难犯错误。

overridefunonCreate(savedInstanceState:Bundle?)overridefunonCreate(savedInstanceState:Bundle) 检查是否存在对应星期的数据如果有，返回UI并且渲染

interfaceinterfaceForecastDataSource funrequestForecastByZipCode(zipCode:Long,date:Long):3.zipzip

1.1.classForecastProvider(valsources:List<ForecastDataSource>ForecastProvider.SOURCES)companionobjectvalDAY_IN_MILLIS=1000*60*60*valSOURCES=listOf(ForecastDb(),forecastforecast 1.1.funrequestByZipCode(zipCode:Long,days:Int): =sources.firstResult{requestSource(it,days,zipCode)}1.inline1.inlinefun<T,R:Any>Iterable<T>.firstResult(predicate:(T)-throwNoSuchElementException("Noelementmatchingpredicate

:(elementinvalresult=if(result!=null)return7.

T=R=T=R=

funrequestSourcefunrequestSource(source:ForecastDataSource,days:Int,zipCode:ForecastList? valres=source.requestForecastByZipCode(zipCode,returnif(res!=null&&res.size()>=days)reselse5. 1.1.privatefuntodayTimeSpan()=System.currentTimeMillis()/DAY_IN_MILLIS*DAY_IN_MILLISclassForecastProvider(valsources:List<ForecastDataSource>ForecastProvider.SOURCES)companionobjectvalDAY_IN_MILLIS=1000*60*60*valSOURCES=listOf(ForecastDb(), funrequestByZipCode(zipCode:Long,days:Int): =sources.firstResult{requestSource(it,days,zipCode)}privatefunrequestSource(source:RepositorySource,days:zipCode:Long):ForecastList? valres=source.requestForecastByZipCode(zipCode,returnif(res!=null&&res.size()>=days)reselse privatefuntodayTimeSpan()=System.currentTimeMillis()DAY_IN_MILLIS*20.

classForecastDb(valforecastDbHelper:ForecastDbHelper=ForecastDbHelper.instance,valdataMapper:DbDataMapper=:ForecastDataSourceoverridefunrequestForecastByZipCode(zipCode:Long,forecastDbHelper.use10. classclassForecastServer(valdataMapper:ServerDataMapper= valforecastDb:ForecastDb=ForecastDb()):ForecastDataSource{ overridefunrequestForecastByZipCode(zipCode:Long,date:ForecastList?valresult=valconverted=dataMapper.convertToDomain(zipCode,returnforecastDb.requestForecastByZipCode(zipCode, 11.datadatabasedatadatabase

domain domain domaindomain

RequestForecastCommand(valzipCode:valforecastProvider:ForecastProvider=ForecastProvider()):Command<ForecastList>companionobject{valDAYS=7overridefunexecute():ForecastListreturnforecastProvider.requestByZipCode(zipCode,\hAndroidDevelopersrepository查看相应的提交。FlowFlowcontrol和Flowcontrol和Flowcontrol和rangesFlowcontrol和IfIf toast("xisgreaterthan}elsetoast("xequalstoast("xissmallerthan7.1.1.valres=if(x!=null&&x.size()>=days)xelse1.1.valz=if(condition)xelse WhenWhen

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可以进入\hKotlin datadataclassForecast(valid:Long,valdate:Long,valdescription:valhigh:Int,vallow:Int,valiconUrl:

1.1.privatefun<T:Any>requestToSources(f:(ForecastDataSource)->T?):T =sources.firstResult{f(it) funrequestByZipCodefunrequestByZipCode(zipCode:Long,days:Int):ForecastList=requestToSources{valres=it.requestForecastByZipCode(zipCode,if(res!=null&&res.size()>=days)reselsefunrequestForecast(id:Long):Forecast=requestToSources{1.1.funrequestDayForecast(id:Long):overrideoverridefunrequestDayForecast(id:Long):Forecast?=forecastDbHelper.use{valforecast=parseOpt{DayForecast(HashMap(it)) if(forecast!=null)dataMapper.convertDayToDomain(forecast)elsenull5. 1.1.funSelectQueryBuilder.byId(id:Long): =whereSimple("_id=?",

1.1.overridefunrequestDayForecast(id:Long): =throw 是表达是非常重要的，当你使 处理边界的问题或者当抛出异常的时候。

valx=in0..10->in11..20->else->throwvalx=try{doSomething()}catch{nullclassclassvalid: valforecastProvider:ForecastProvider=ForecastProvider()):Command<Forecast>overridefunexecute()=6. 提供一个新的提供一个新的提供一个新的提供一个新的

forecastforecastpublicpublicclassDetailActivity:AppCompatActivity()companionobjectvalID=valCITY_NAME= 7. \h\htools:text="Few

title=asyncasync valresult=RequestDayForecastCommand(intent.getLongExtra(ID,-1)).execute()uiThread{bindForecast(result)4. importpri