中文版b4a新手指南-第14-15章语言画图

Getting Trial InstallingBasic4AndroidandAndroid Installandconfigure InstallingAndroid Myprogram(My Secondprogram The andToolbar Code Undo– Collapsea Collapsea Collapsethewhole Builtin Jumptoa Highlightingoccurrencesof Moduleandsubroutinelists Screensizesand Specialfunctionslike50%x, PerXToCurrent,PerYToCurrent- DipToCurrent- Workingwithdifferentscreensizes/numberof Screen Supportingmultiplesceens-tipsandbest Howtochangetheviewssizeandtextsize? The Launchan Createanew Emulator Process Exchangingfileswiththe ConnectingarealdeviceUSB/B4A youneedtoinstallB4A-Bridgeonyourdevice RunB4A-Bridgeonyour ConnecttheIDEtothe The The Generate BringTo SendTo DuplicateSelected RemoveSelected Change Connectdeviceor General Image Properties Layout Select Addingviewsby Designer SimpleAutoScaleexamplewithonlyonelayout SameAutoScaleexamplewithportraitandlansdsclayout AutoScalemoreadvanced UI ProcessandActivitylife Howdowehandleit Processglobal Activity SubActivity_Create(TimeAs Globalsversus SubActivity_ResumeSubActivity_Pause(UserClosedAs Activity.Finish/ Variablesand Variable Namesof Declaring Simple Array Arrayofviews Type Process Activity Activity Class Code Service Searchfunctioninthe TheB4Aation Example User example(UserInterface.b4a) TabHostexample Buttontoolboxexample Programwith3Activities Basic Program Activity_Create(TimeAsBoolean) Activity_Pause(UserClosedAsBoolean) Boolean If–Then–End Select– Loop For– For- Do- Callinga CallingaSubfromanother Returned Standard Additionallibraries Errormessage"Areyoumissingalibrary String File Text Graphics/ Drawingtest steps Drawingrotatingbitmaps/ Simpledraw VB6versus "Pleasesaveproject" "Areyoumissingalibraryreference" Howloading/updatinga Whendoweneedto'Initialize'andwhen Splitalonglineintotwoormore Avoidclosinganapplication/capturekeycodeslikeBack/UnwantedeventslikeClick,Touchor Adding removeaViewwiththe "Processhastimeout" Gettingapicturefromthe Howtodeletex.balfilesorotherfilesfroma Blockascreen Closesecond Takingascreenshot Aftercompiling,wherearethe Runanapplicationfromanother HowtopassanArraytoa Gettinglanguageandcountryfrom Whereistheapk Whyismyapkfilename Whyismyapkfilename SelectTrue/Case Fillanarraywithrandomnumberswithout Detectscreen Somefunctionsdon'tworkin Callingtheinternal GettheAlpha/Red/Green/ Getdevice GenerateaClick "Outofmemory"Error/ Removethescrollbarfroma Checkifdirectory SetFullScreenin ChangeEditTextinput Sortingafilelistaccordingtolastmodified Getthedpivaluesofthedevice(dotsper Findingjavaprogram MaincontributorsErelUziel KlausChristl(klaus)TosearchforagivenwordorsentenceusetheSearchfunctioninthe Allthesourcecodeandfilesneeded(layouts,imagesetc)oftheexampleprojectsinthisguideareincludedintheSourceCodefolder.AmoreadvancedguidecanbedownloadedUser'sBasic语 在计算机语言中,BASIC(英文全称:Beginner'sAll-purposeSymbolicInstructionCode)是简单易用的高级编程语言的一种。BASIC语言1964年由Dartmouth学院（位于的新罕布什尔州NewHampshire,USA）的JohnGe eKemeny和ThomasEugeneKurtz二人创立。那是主要用于微软的VB(VisualBasic).程序 ProcessandActivitylife'Activitymodule'Activity模块Sub'Theseglobalvariableswillbedeclaredoncewhentheapplicationstarts.'Thesevariablescanbeaccessedfromallmodules.'应用启动是一些全局变量在这里EndSubSubGlobals'Theseglobalvariableswillberedeclaredeachtimetheactivityis'Thesevariablescanonlybeaccessedfromthismodule.'这里的的全局变量在Activity创建时。EndSubActivity_Create( TimeAsBoolean)EndSubSubActivity_ResumeEndSubSubActivity_Pause(UserClosedAsEndProcess_Globals程序 这里的全局变量在整个程序的生命周期中都有效，可在任何整个程序的任何地方存.2Globals这里Activity的全局变量。在Activity的生命周期中有效，只能在本Activity内存取14.1.314.1.3Activity_Create TimeAsBoolean)程序如果变量和对象只初始化一次，可以用参数TimeSubActivity_Create( TimeAsBoolean)IfTime=TrueThenEndIfEnd14.1.414.1.4Activity_ResumeactivityActivity设置Subet_main.TextfilterEnd14.1.514.1.5Activity_PauseUserClosedAsBoolean)程序当activity这里你需要保存activity参数，这些参数当activityActivityActivityActivity_Resume,正常情况是触发Globals,Activity_CreateandActivity_Resume.UserclosedSubActivity_Pause(UserClosedAsBoolean)camEx.Release'相机控制gps130.Stop'停止Gps控制End程序流:例子:

Sub,它会返回到调用25行执行btnAction表达 例如：2+3是一个算术表达式计算结果是5。表示式里的变量指向此变量的内存地址，比如y+6是一个表达式。4=4True。数学表达 +x+3加-x-3减*x*2乘/x/2除xMod2Power(x,y)1幂优先级:在一个表达式里，1234+5*3+2= >4+15+(4+5)*(3+2)= >9*(4+5)2*(3+2)= >92* >81*11Mod4= >Modistheremainderof10/ >23atthepowerof-22=-(-2)2=关系表达 B4ATrueFalse=x=x<>>x><x<x>=x<=布尔表达 或ZXOrYZTrueXYTrue与ZXAndYZTrueXYNot(非X= Y=Not(X)那么Y=XYZZ条件语 BasicIf–Then–End Iftest1Then'code1ElseIftest2Then'code2'code3EndIf当执行到If关键字时test1test1Truecode1ElseIf。EndIf。test1Falsetest2test2Truecode2Else。EndIf。test2Falsecode3EndIf2True另一些例子Ifb=0a EndIfb0Thena Ifb=0a a=1EndIfIfb0Thena0Elsea 同一行的写法备注：B4AVB Else Ifb=0Thena=0:c=B4AVB有很大的不同。 Ifb=0 Ifb=0a= a=End c=c= EndB4ACarriageReturnCRSelect–Case分支语 也有叫开关语句的，检测TestExpression的值，根据不同的Expressions执行不同的分支常规用法Select TestExpression检测表达式Case' ExpressionList1表达式Case ' ExpressionList2另一个Case 'code3EndSelectSelectCase结构执行顺序先计算TestExpression的值TestExpression的值ExpressionList1EndSelectTestExpression的值ExpressionList2EndSelectTestExpression则执EndSelectSelectCase123 Selecta TestExpressionabCase12,Select TestExpressionCase"A","B",SubActivity_Touch(ActionAsInt,XAsFloat,YAsFloat)SelectActionCaseActivity.ACTION_DOWNCaseActivity.ACTION_MOVECaseActivity.ACTION_UPEndSelectEndSub注释：B4AVB SelectValue SelectCaseValueCase1,2,3,4,8,9,10 Case1To4,8To9VBCase1To4B4A循环语句 BasicFor– For–Next循环用于知道循环次数的情况。Forin1Ton2Step n1Specific n2n3i=n1ForNextspecificcodeNextin3.i=i+n3.检查iYes,继续执行循环体For到Next。No,Next下面的语句.如果步长是+1可以省略。Fori=0To Fori=0To10Step Fori=n3To0Step-1ExitForNext循环Fori0To A'IfA0Then 'codeContinue可以短路循Fori0To A'codeIfA0ThenContinuecode2'code2:B4AVB VBNext ExitVB循环变量增加在Next后面Exit后还有For- Basic4Android2.2及以后的版本引进。For-Next循环的变体。范例ForEachnAsTypeIn nSpecific For–Each循环的执行顺序开始nn=ForNextspecificcodeNextnNonn=YesNextFor-Each的例子DimNumbers()AsIntDimSumAsIntNumbers=ArrayAsInt(1,3,5,2,9)Sum=0ForEachnAsIntInNumbersSum=Sum+nForNext循环DimNumbers()AsIntDimSumAsIntDimiAsNumbers=ArrayAsInt(1,3,5,2,9)Sum=0Fori=0ToNumbers.Length-1Sum=Sum+Numbers(i)ForEach的强大ForEachlblAsLabelInActivitylbl.TextSize=20For-Next循环Fori=0ToActivity.NumberOfViews-1DimvAsViewv=Activity.GetView(i)IfvIsLabelThenDimlblAsLabellbl=vlbl.TextSize=20EndIfDo- Do–Loop2DoWhile test testTrue执行DoUntil test任何表达 codetestDoWhileLoop开始testTrueFalseLoopDoUntilLoop执行顺序开始testFalseTrueLoopDoWhiletest'codeIfa0Then a=0'codeDoUntilLoopDimi,nAsi=DoUntili=10'codei=i+1DoWhileLoopDimi,nAsi=DoWhilei<10'codei=i+1textList对象:DimlstTextAsListDimlineAsStringDimtrAsTextReaderline=tr.ReadLineDoWhileline<>Nullline=tr.ReadLine注释:B4AVB ExitVBExit后面多了VB里还有下面两种循环B4A ' 'LoopWhile LoopUntil SubBasci4Android的代码Subsubs。代码是按顺序执Sub Declaring Sub用下面的方法SubCalcInterest(CapitalAsDouble,RateAsDouble)AsDoubleReturnCapital*Rate/100EndEndSubs的总是在模块级，不能在一个Sub中另一个Sub调用一个 sub的名字来调用一Interest=CalcInterest(1234, sub Sub 从另一模块调用 在code模块你的sub可以在任何其他模块里调用，但必须加code模块名前缀范例:如果CalcInterest在MyModule里，然后调用它必须这样Interest=MyModule.CalcInterest(1234,Interest=CalcInterest(1234,Su 总体来说，你可以用任何合法的名字给sub命名。建议用有一定意义名，象例子中CalcInterest，这样你可以大概知道这个sub能干什么Sub2个subSubCalcInterest(CapitalAsDouble,RateAsDouble)AsDoubleReturnCapital*Rate/100EndSub的参 Subsub名称的后面，参数表放在括号里。参数类型直接在参数表中。SubCalcInterest(CapitalAsDouble,RateAsDouble)AsDoubleReturnCapital*Rate/100EndSub的返回 Sub可以有返回值，返回值可以是任何对象。Return关键字。SubCalcInterest(CapitalAsDouble,RateAsDouble)AsDoubleReturnCapital*Rate/100End事件 在面象的程序中，的对象可以用事件驱动。最常用的事件 View时触发SubButton1_Click'YourcodeEnd View时触发SubButton1_LongClick'YourcodeEndTouch(ActionAsInt,XAsFloat,YAs3种动作Activity.Action_DOWN,用户用手指按屏幕 XYActivityTouch事件SubActivity_Touch(ActionAsInt,XAsFloat,YAsFloat)SelectActionCase'YourcodeforDOWNactionCaseActivity.ACTION_MOVE'YourcodeforMOVEactionCaseActivity.ACTION_UP'YourcodeforUPactionEndSelectEndCheckChanged(CheckedAsBoolean)CheckBoxRadioButton触发。CheckedTrue未勾选为False。范例SubCheckBox1_CheckedChange(CheckedAsIfChecked=True'Yourcodeifchecked'YourcodeifnotcheckedEndIfEndKeyPress(KeyCodeAsInt)As,False,范例SubActivity_KeyPress(KeyCodeAsInt)AsBooleanDimAnswAsIntDimTxtAsIfKeyCode=KeyCodes.KEYCODE_BACKThen'ChecksifKeyCodeisBackKeyTxt="Doyoureallywanttoquittheprogram?"Answ=Msgbox2(Txt,"ATTENTION","Yes","","No",Null)'MessageBoxIfAnsw=DialogResponse.POSITIVEThen'IfreturnvalueisYesthenReturnFalse 'Return=FalsetheEventwillnotbeconsumed weleavetheprogramReturnTrue 'Return=True theEventwillbeconsumedtoavoidEndIf leavingtheprogramEndIfEndSub库irres B4A的库可以包含很多对象和函数。B4A另，AndrewGraham(agraham)是经常开发库的用户，用户可以库增补到LibTab对于附加库检查是否是的版本IDELibTab标准 B4AB4AC:\ProgramFiles\Anywhere附加库文件 D:\Basic4Android\AddLibraries当你安装新版本的B4A，所有的标准库会自动更新，但不包括附加库。这样的好处就是你的附加库你不用关心，安装新版本的B4A附加库不受影响。如果你安装附加库文件夹，你必须在IDE里配置它的路径。Tools/ConfigurePaths:输入文件夹后点.按钮就行了错误信息"Areyoumissingalibrary 如果你看到了这个错误信息，意味着你忘记在LibTab里勾选库字符串操 字符串替换范例txt=txt=txt.Replace(",",结果字符串操控函数列表 TrueSearchFor True如果后缀是SuffixEqualsIgnoreCase(Other)True如果字符串等于Other , SearchFor从index SearchFor Replace(, 返回被Replacement替换的新字符串 True如果字符串的前缀是 BeginIndexSubstring2(BeginIndex,EndIndex)BeginIndexEndindex NumberFormat(NumberAsDouble,MinimumIntegersAs umFractionsAsNumberFormat(12345.6789,0,2)=NumberFormat(1,3,0) =001NumberFormat(Value,3,0) variablescanbeused.NumberFormat(Value+10,3,0)arithmeticoperationscanbeused.NumberFormat((lblscore.Text+10),0,0)ifonevariableisastringaddNumberFormat2(NumberAsDouble,MinimumIntegersAsInt, umFractionsAsInt,MinimumFractionsAsInt,GrouUsedAsBoolean)NumberFormat2(12345.67,0,3,3,True) =12,345.670定时对象 TimerticktimerUI线程的其注意

TimerUI线程忙的时候不会触发（Timer时间在Activity是Paused是不会被触发，比如一个交互框可见时三个参数 初始化EventName和interval参数Timer1.Initialize(EventNameAsString,IntervalAsLong) Timer1.Initialize("Timer1",1000) Timer1.Interval= Timer1.Interval=1000,1 Timer Timer1.Enabled= TheTickroutineiscalledeverytimeinterval. SubTimer1_TickTimer必须在Process_Global里SubProcess_GlobalsDimTimer1AsTimerTimer还必须在Activity_Create初始化SubActivity_Create( TimeAsBoolean)IfTime=TrueThenTimer1.Initialize("Timer1",1000)EndIfTimerTickSubTimer1_Tick'DosomethingEndRotatingNeedle.文件 文件对象File 预定义的文件对象file有很多功能–IDEFiles下的文件。你不能在这个文件夹创建新文件(apk文件)。File.DirInternal/这两个文件夹在设备的主器和应用程序。缓存文件夹可能作系统删除如果系统需要的空间卡的 SD这个文件夹是：<storage注意，调用上面的两个文件夹将需要添加您的应用程序external_storage。建议:你可以检查是否有卡，及卡是否可用。检查一个文件时候存在可用File.Exists(DirAsString,FileNameAs文件对File包括一些读写文件的方法。File.OpenOutput(DirAsString,FileNameAsString,AppendAs,File.OpenInput(DirAsString,FileNameAs为文件打File.WriteString(DirAsString,FileNameAsString,TextAsFile.ReadString(DirAsString,FileNameAsString)AsFile.Wriist(DirAsString,FileNameAsString,ListAs写List的所有值到一个文件，所有的值都转换为字符串，每个值在单独的一行。注意，如果list的值里有换行符，将会分成多行，当你再时变成多个项目。File.ReadList(DirAsString,FileNameAsString)AsFile.WriteMap(DirAsString,FileNameAsString,MMpertiesWikipediathefreemap为一个设置文件。File.ReadMap(DirAsString,FileNameAsString)AsMapFile.Copy(DirSourceAsString,FileSourceAsString,DirAsString,FileAsAssetsFile.Delete(DirAsString,FileNameAsFile.ListFiles(DirAsString)Aslist。DimList1AsList1=List1可以在SubGlobals里File.Size(DirAsString,FileNameAsassets文件命名 Androida-z,AZ,09_*不允许。:MyFile.txtMyFile.txt和myfile.txt子 Subfodes 安卓上你可以创建自己的 ImageView1.Bitmap=LoadBitmap(File.DirInternal&"/Pictures", 和文件名之间也需要"/"分ImageView1.Bitmap=LoadBitmap(File.DirInternal,写文本文件对象 这里有两个常用的文件文件操控对象：TextWriter-outputstreamTextWriter范例DimWriterAsTextWriterWriter.Initialize(File.OpenOutput(File.DirRootExternal,"Test.txt",False))Writer可以在SubGlobals里TextWriter.Initialize2(OutputStreamAsOutputStream,EncodingAs-outputstreamTextWriterEncodingCodePageCharacterSet(见下一章)范例DimWriterAsWriter.Initialize2(File.OpenOutput(File.DirRootExternal,"Test.txt",False),"ISO-8859-Writer可以在SubGlobals里TextWriter.Write(TextAsTextWriter.Wriine(TextAsTextLFChr(10)TextWriter.Wriist(ListAsCRLF2(ReadList2个项目)。DimWriterAsTextWriter ine("Thisistheline") ine("Thisisthesecondline")14.10.5读14.10.5读文本文件对象 这里有两个常用的文件文件操控对象：TextWriterDimReaderTextReaderReader可在SubGlobals里TextReader.Initialize2(InputStreamAsInputStream,EncodingAs范例DimReaderReader可以在SubGlobals里范例txt=TextReader.ReadLineAsThenewlinecharactersarenotDimReaderAsTextReaderDimlineAsStringline=Reader.ReadLineDoWhileline<>Nullline=Reader.ReadLineList对象。范例List1=14.10.6文本编码Text 字符表、代码页都是一个意思，可以互换替代。UTF-8WindowsASCII和ASCII128个字符33256个字符包含ASCII128个字符。在西方国家许多文件由windows程序生成，用的是ANSI字符集。例如:Excelcsv文件,记事本文件 UTF-UTF-16UTF-US- ASCIIISO-8859-1ANSIANSIwindowsWindows-1252字符集。如果你Windows用的文件也用Windows-1252字符集。WindowsAndroidAndroid,LFLineFeed)Chr(10)Windows有CRCarriageReturnChr(13LFChr(102个字符为行结束。如果你好写Windows用的文件要自己加CR字符。 Chr(13)&TextReaderTextWriterInitialize2CSVExcelcsv文件小建议csv另存UTF-8编码文Notepad+UTF-8或读整个文件用TextReader.Initialize2方法，编码用"Windows-1252"TextWriter.InitializeLoadCSVLoadCSV2见StringUtils库DimtxtAsStringDimtrAsTextReadertxt=tr.ReadAllDimtwAslstTest=StrUtil.LoadCSV2(File.DirInternal,"TestCSV1_W.csv",";",BOM(ByteOrderUTF-8Windows-1252编码的文本编辑器或Web浏览器会显示Notepad++NotePadUTF-8BOM另一个转换Windows-1252UTF-8的方法见下面代Dimvar,resultAsStringvar="Gestió"DimarrByte()AsarrByte=var.GetBytes("Windows-result=BytesToString(arrByte,0, ength, Lists类似动态数组ListLists很常用，很多的例程都 LoadCSV,DBUtils模块 ExecuistView,ExecuteHtml,ExecuteJSONCharts模 保存变list List.DimList1AsListList1.AddAll(ArrayAsInt(1,2,3,4,list1:DimList1AsList1.Initialize2(ArrayAsInt(1,2,3,4,DimList1AsDimSomeArray(10)AsString'FillthearrayAdd(itemAslistAddAllArrayAsString("value1value2"))list的最后增加数组的所有值。List1.AddAll(ArrayAsInt(1,2,3,4,AddAllAt(IndexAsIntListAsList)在index位置数组所有元素。List1.AddAll(12,List2)List1.AddAllAt(12,ArrayAsInt(1,2,3,4,InsertAt(IndexAsInt,ItemAs在index位置itemAsaresultallitemswithindexlargerthenthespecifiedindexareRemoveAt(IndexAsInt)List可以任何对象，但需要在processglobal你，这里的对象不包括Activity对List的尺寸Get(IndexAsnumber=For-looplist的所有值Fori=0ToList1.Size-1DimnumberAsIntnumber=List1.Get(i) ist(DirAsString,FileNameAsString,ListAs File.ReadList(DirAsString,FileNameAsList1=File.ReadList(File.DirRootExternal,List1.Set(IndexAsInt,ItemAsList1.Set(12,List可以排序(所有项目都是数值或字符):Sort(AscendingAsBoolean) sortascending sortSortCaseInsensitive(AscendingAsList Map是一个内存中键和值的集合对象，所有函数的详细描述见Map章节。Map对应用设置非常有用, 用于设置Map Map.DimMap1AsMap增加一个新元素Put(KeyAsObject,ValueAsGet(KeyAsLanguage=取指定位置的键或值GetKeyAtGetValueAt可以遍历所有项目。GetKeyAt(IndexAsKey=GetValueAt(IndexAsValue=ContainsKey(KeyAsIfMap1.ContainsKey("Language")Msgbox("Thereisalreadyanentrywiththiskey!","ATTENTION")EndRemove(KeyAs File.WriteMap(DirAsString,FileNameAsString,MMap)File.WriteMap(File.DirInternal,"settings.txt",mapSettings)Map保存为文件ReadMap(DirAsString,FileNameAsmapmapSettings=File.ReadMap(File.DirInternal,File.ReadMap2(DirAsString,FileNameAsString,MReadMap.ReadMap2增加了一个map参数。ReadMap2可以按map需要强制排序。图/画Graphics/ 概 Canvas画布对象。Canvascanvsa画布初始化时，会创建一个新的位图，此位图的背景就是它所在视图的背景，意CanvasInvalidate方法刷新它。Canvas画布可以临时限定在指定区域(只影响这个区域)ClipPath方法RemoveClip方法。Canvas这是一个antivity对象，不能在SubProcess_Globals下CanvasBitmapBitmap1as x,yx1,y1,x2,y2As Coloras SrcRectDestRactRect1As 矩形RectFilledAs (True用的最多的绘图函数DrawBitmap(Bitmap1AsBitmap, Rect, Bitmap1SrcRect源矩形,DestRect目标矩形DestRect和SrcRectDrawBitmapRotated(Bitmap1AsBitmap,SrcRe Rect,DestRe Rect,DegreesAsFloat)DrawCircle(xAsFloat,yAsFloat,RadiusAsFloat,ColorasInt,FilledAsBoolean,StrokeWidthAsFloat)xyRadiusDrawColor(ColorAsColorsDrawLine(x1AsFloat,y1AsFloat,x2AsFloat,y2AsFloat,ColorasInt,StrokeWidthAsFloat)DrawRect(Rect1AsRect,ColorAsInt,FilledAsBoolean,StrokeWidthasDrawRectRotated(Rect1AsRect,ColorAsInt,FilledAsBoolean,StrokeWidthAsFloat,DegreesAsFloat)DrawText(TextAsString,xAsFloat,yAsFloat,Typeface1AsTypeFace,TestSizeAsFloat,ColorAsIntAlign1AsAlign)DrawTextRotated(TextAsString,xAsFloat,yAsFloat,Typeface1AsTypeFace,TestSizeAsFloat,ColorAsIntAlign1AsAlign,DegreesAsFloat)画旋转文本画图测试程 第一 此例程在:SourceCode\Graphics\RotatingNeedle\GraphicsCanvasCanvas画位图.通常在这几个视图上画:Activity,Panel,ImageViewBitmap.Canvas2个初始化方法。 Canvas在例程中，用了几个画图函数在Activity和Panel上画了几个图形，panel在布局文main2CanvasIntheexampleprogramwe'lluseseveraldrawingfunctionsanddrawontotheActivityandapnlGraphdefinedinthe'main'layoutfile.Hereweneedtwo 开 和初始首先须视图和对象，需要PanelSubDimpnlGraphAsDimcvsActivity,cvsGraphAsCanvasEndSub然后须加载布局文件，初始化SubActivity_Create( TimeAsBoolean)'加载布局文件'activityCanvas'panel初始化CanvasEnd 划Activity_ResumeActivity上画横线:DrawLine(x1AsFloat,y1AsFloat,x2AsFloat,y2AsFloat,ColorasInt,StrokeWidthAsFloat)Where:x1,y1x2,y2StrokeWidth线宽:在ActivitycvsActivity.DrawLine(20dip,20dip,160dip,20dip,Colors.Red,然后pnlGraph上画横:坐标是相对于视图的左上角,Panel在pnlGraphcvsGraph.DrawLine(20dip,20dip,160dip,20dip,Colors.Red,画矩画矩Activity上画一个空的矩形函数用DrawRect(Rect1AsRect,ColorAsInt,FilledAsBoolean,StrokeWidthasFloat)Where:Filled:False只画边框TrueRect.要在ActivityRectDimrect1Asrect1.Initialize(20dip,40dip,150dip,100dip)cvsActivity.DrawRect(rect1,Colors.Blue,False,3dip)接下来同样的Rect对象画在pnlGraph:在pnlGraphcvsGraph.DrawRect(rect1,Colors.Blue,True,画画Activity上画一个空心圆DrawCircle(xAsFloat,yAsFloat,RadiusAsFloat,ColorasInt,FilledAsBoolean,StrokeWidthAsFloat)Wherex,yRadiusFilled:FalseTrueStrokeWidthFilledTrue无关在ActivitycvsActivity.DrawCircle(220dip,70dip,30dip,Colors.Green,False,panel上画一个填充颜色的圆.因此可以先画一个填充圆，再画一个边框圆。在pnlGraphDimcenterX,centerY,radiusAsFloatcenterX=220dipcenterY=70dipradius=30dipcvsGraph.DrawCircle(centerX,centerY,radius,Colors.Green,True,3dip)cvsGraph.DrawCircle(centerX,centerY,radius,Colors.Red,False,3dip)画文画文:DrawText(TextAsString,xAsFloat,yAsFloat,Typeface1AsTypeFace,TestSizeAsFloat,ColorAsIntAlign1AsAlign)TextTypeFace1TextSizeisdip:"LEFT"CENTER"ActivitycvsActivity.DrawText("Testtext",20dip,150dip,Typeface.DEFAULT,20,_Colors.Yellow,"LEFT")pnlGraph上画旋转的文本3个变量:refX和 基点坐 DimrefX,refY,hlAsFloatrefX=150diprefY=180diphl=5dip在pnlGraphcvsGraph.DrawTextRotated("Testtext",refX,refY,Typeface.DEFAULT,_20,Colors.Black,"RIGHT",45)在文本的坐标基点上画个+cvsGraph.DrawLine(refX-hl,refY,refX+hl,refY,Colors.Red,1dip)cvsGraph.DrawLine(refX,refY-hl,refX,refY+hl,Colors.Red,画旋转位图/旋转指 :在第一个例程里介绍了DrawBitmapRotated函数.2个模式3ooo

2如果有这样的指针，需要做些计算才能使指针旋转为避免计算，要这样的指针，只要旋转位图，指针就是旋转效果。SubDimAngleStepAs 步进角度DimAngleAsFloat :Angle=-AngleStepDimModeAsBoolean :Mode=TrueDimTimer1AsTimerEndSub False=SubDimbtnGoStop,btnStep,btnModeAsButton pass,csvNeedleAsCanvas pass,bmpNeedleAsBitmap pass,imvNeedleAsImageView pass,SRectNeedle,DRectNeedleAsRectEndSub32个位图3个矩形，一个罗盘,2个指针（源和目标Activity_Create的代码:SubActivity_Create( TimeAsBoolean)Dimx,yAsFloat2pass.Bitmap= ImageViewx=(100%x- pass.Width)/2y=(100%y- pass.Height)/2 pass,x,y, Activity.AddView(imvNeedle,x,y, pass.Initialize(0, 和罗盘ImageView尺寸相ImageViewCanvasx=( pass.Width-bmpNeedle.Width)/2y=( pass.Height-bmpNeedle.Height)/2SRectNeedle.Initialize(0,0,bmpNeedle.Width,bmpNeedle.Height)DRectNeedle.Initialize(x,y,x+bmpNeedle.Width,y+bmpNeedle.Height)ImageViewCanvas初始化指针矩形（源和目标Endtimer200毫秒Timer1_TickSubDimAngle1AsAngle1=Angle=(Angle+AngleStep)Mod360IfMode=TrueThen EndIfEndSub

用ModModeTrue旋转指针ImageView用以更新ModeFalse,旋转罗盘用新角度画罗盘,ImageViewSubbtnStep_ClickEndSubIfTimer1.Enabled=TrueThenTimer1.Enabled=FalsebtnGoStop.Text="Go"btnStep.Visible=TrueTimer1.Enabled=TruebtnGoStop.TExt="Stop"btnStep.Visible=EndIfEndSubTimer1TruetimerTimer1FalsetimerTimer1.EnabledTruebtnStepSubbtnMode_ClickMode=Not(Mode)IfMode=TrueThenbtnMode.Text="Needleturns"csvNeedle.DrawRect(DRectNeedle,Colors.Transparent,True,1) btnMode.Text="Compassturns"csvNeedle.DrawBitmap(bmpNeedle,SRectNeedle,DRectNeedle)EndAngle=Angle-AngleStepEndModeNOTTureFalse，FalseModeTrue旋转指针设置按钮文本"NeedleModeFalse,简单画图函 SourceCode\Graphics\SimpleDrawFunctions\SimpleDrawFunctions.b4a3panelToggleButton你可以通 作看到不同图层的显示和隐藏组合效果activity用ToggleButtons按钮可显示或隐藏不同的图Panel是灰色背景:一个透明的圆activity的背景在圆中显示出一个半透明矩形activityLayer(0)图层上，触摸屏幕并移动，蓝色的透也是透明背景你可以通 作看到不同图层的显示和隐藏组合效果代码分析在SubGlobalsroutine视图和变量:SubDimpnlLayer(3)AsPanelDimcvsLayer(3)AsCanvasDimbtnLayer(3)AsToggleButtonDimrect1AsRectDimbmpBackgroundAsDimbdwBackgroundAsDimxc,yc,x1,y1,x2,y2,r1,r2,h,wAsFloatEndSub3Canva1Bitmap位图activity注意这里用数组了三个panel、canvas、DimpnlLayer(3AsPanelDimpnlLayer0pnlLayer1pnlLayer2AsSubActivity_Create( TimeAsBoolean)DimiAsInt TimeThenActivity.Background= Time=True初始化视加载Rose2.jpg文件到x1=2%xw=y1=100%y-55diph=50dipFori=0To2pnlLayer(i).Initialize("pnlLayer"&i)Activity.AddView(pnlLayer(i),0,0,100%x,85%y)pnlLayer(i).Tag=ix2=x1+i*33%xActivity.AddView(btnLayer(i),x2,y1,w,h)btnLayer(i).TextOn="Layer"&i&"ON"btnLayer(i).TextOff="Layer"&i&"OFF"btnLayer(i).Checked=TruebtnLayer(i).Tag=iEndIfEndSub循环体初始化图层初始化开关按钮ToggleButtons定义了同一