17.如何使用SurfaceView計(jì)時(shí)繪點(diǎn)或線大家常撰寫(xiě)View的子類(lèi)別，然后在其onDraw()函數(shù)里繪出各式各樣的圖形，例如畫(huà)出點(diǎn)或是直線。不過(guò)，基本上onDraw()函數(shù)是在Canvas畫(huà)完所有線條等圖形后，才一塊兒將Canvas顯示出來(lái)。然而，當(dāng)我們想再畫(huà)出一些線條之后，停個(gè)幾秒鐘之后，才繼續(xù)繪出后續(xù)的圖形，這種有停頓的計(jì)時(shí)性繪圖，又該如何呢？例如，先繪出一條綠色線段：停頓5秒鐘之后，才畫(huà)出一條黃色線段：這時(shí)，使用SurfaceView會(huì)是一個(gè)好方法。如下之范例程序代碼：/*ac01.java*/packagecom.misoo.ppvv；importandroid.app.Activity；importandroid.os.Bundle；importandroid.widget.LinearLayout；publicclassac01extendsActivityOverrideprotectedvoidonCreate(Bundleicicle)super.onCreate(icicle)；MySurfaceViewmv=null；trymv=newMySurfaceView(this)；catch(InterruptedExceptione)e.printStackTrace()；/-LinearLayoutlayout=newLinearLayout(this)；layout.setOrientation(LinearLayout.VERTICAL)；LinearLayout.LayoutParamsparam=newLinearLayout.LayoutParams(200,150)；param.topMargin=5；layout.addView(mv,param)；/-setContentView(layout)；/*MySurfaceView.java*/packagecom.misoo.ppvv；importandroid.content.Context；importandroid.graphics.Color；importandroid.view.SurfaceHolder；importandroid.view.SurfaceView；classMySurfaceViewextendsSurfaceViewimplementsSurfaceHolder.CallbackSurfaceHoldermHolder；privateDrawThreadmThread；privatedwListdwl；MySurfaceView(Contextcontext)throwsInterruptedExceptionsuper(context)；getHolder().addCallback(this)；dwl=newdwList()；dwl.begin_record()；dwl.record(30,30,0,0)；dwl.record(100,100,1,Color.GREEN)；Thread.sleep(50)；dwl.record(100,30,1,Color.YELLOW)；Thread.sleep(60)；dwl.record(30,30,1,Color.BLUE)；Thread.sleep(40)；dwl.record(30,100,1,Color.RED)；publicvoidsurfaceCreated(SurfaceHolderholder)mHolder=holder；mThread=newDrawThread()；mThread.start()；publicvoidsurfaceDestroyed(SurfaceHolderholder)mThread=null；publicvoidsurfaceChanged(SurfaceHolderholder,intformat,intw,inth)/-classDrawThreadextendsThreadDrawThread()super()；Overridepublicvoidrun()dwl.draw(mHolder)；/*dwList.java*/packagecom.misoo.ppvv；importjava.util.ArrayList；importjava.util.Iterator；importandroid.graphics.Canvas；importandroid.graphics.Paint；importandroid.view.SurfaceHolder；publicclassdwListprivatePaintpaint=null；privatelongdraw_time；privateArrayListpoList；publicvoidbegin_record()dwPoint.initial_time=System.currentTimeMillis()；poList.clear()；publicvoidrecord(intx,inty,intty,intcolor)dwPointpo=newdwPoint(x,y,ty,color)；poList.add(po)；publicdwList()paint=newPaint()；poList=newArrayList()；publicvoiddraw(SurfaceHolderholder)dwPointpo；longcurr_time；longbase_time=0；intnnn=0；Iteratorit=poList.iterator()；while(it.hasNext()po=it.next()；draw_time=po.m_timeSpan*100；if(nnn=0)base_time=System.currentTimeMillis()；nnn+；/-waiting-docurr_time=System.currentTimeMillis()-base_time；while(curr_timedraw_time)；/-paint(holder,nnn)；publicvoidpaint(SurfaceHolderholder,intk)Canvascanvas=holder.lockCanvas()；dwPointpo；intlastX=0；intlastY=0；Iteratorit=poList.iterator()；for(inti=0；ik；i+)po=it.next()；if(po.m_type=0)lastX=po.m_x；lastY=po.m_y；elsepaint.setColor(po.m_color)；paint.setStrokeWidth(3)；canvas.drawLine(lastX,lastY,po.m_x,po.m_y,paint)；lastX=po.m_x；lastY=po.m_y；holder.unlockCanvasAndPost(canvas)；/*dwPoint.java*/packagecom.misoo.ppvv；publicclassdwPointpublicstaticlonginitial_time；publicintm_x,m_y,m_type；publiclongm_timeSpan；