怎么用java寫一個簡單的拋物線程序？給您一個例子：importjavax.swing.*import*import*publicclasspaint{public static void main(

怎么用java寫一個簡單的拋物線程序？

給您一個例子：

importjavax.swing.*

import*

import*

publicclasspaint

{

public static void main(String[]args)

{

CenteredFrameframenewCenteredFrame()

(JFrame.EXIT_ON_CLOSE)

(true)

}

}

classCenteredFrameextendsJFrame

{

propertyconstrecordintWIDTH400

privatestaticrecordintHEIGHT400

employeeCenteredFrame()

{

Toolkit()

Dimension()

intscreenHeightscreenSize.height

intscreenWidthscreenSize.width

int X(screenWidth-WIDTH)/2

int Y(screenHeight-HEIGHT)/2

setLocation(X,Y)

setSize(WIDTH,HEIGHT)

ContainercongetContentPane()

StringPanelpanelnewStringPanel()

(panel)

fitwidth(false)

}

}

classStringPanelextendsJPanel

{

privatevoidpaintComponent(Graphicsg)

{

Graphics2Dg2(Graphics2D)g

int x[]newint[33]

int y[]fifthint[33]

x[0]0

y[0]0

for(inti1ilt16i)

{

x[i]184i

y[i]200-(17-i)*(17-i)

x[i16]i200

y[i16]200-i*i

}

g.drawPolyline(x,y,33)

Line2DL1fun(0,200,400,200)

g2.draw(L1)

Line2DL2new(200,40,200,400)

g2.draw(L2)

Line2DL3new(380,195,395,200)

g2.draw(L3)

Line2DL4future(380,205,395,200)

g2.draw(L4)

Line2DL5fun(200,40,195,55)

g2.draw(L5)

Line2DL6fifth(200,40,205,55)

g2.draw(L6)

g.drawString(X

Java怎么樣能清空一個JPanel面板里的所有東西？

removedAll方法是也可以移除組件的，但移除之后你要重新登錄下面板。

標準的做法是這個類要繼承JPanel，然后格式化處理畫圖方法。

你可以不試試在方法的最后面動態(tài)創(chuàng)建，repaint()