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該程序有2個單選按鈕。 1:一個圓圈,2:輸出一個正方形。Java-使用AWT添加單選按鈕?
這個程序基本上是設計爲輸出圓形或方形的單選按鈕組。
我的問題是,我不知道如何在按鈕上實現一個動作偵聽器,以便輸出形狀。當我調用方法fm時,在初始化單選按鈕時出現錯誤。顯然我認爲我需要一個主要方法。
請記住,這是java AWT。
如果您想要我添加更多細節或澄清請發表評論。
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.applet.Applet;
public class RadioButton extends Applet
implements ActionListener
{
int choice;
Frame fm = new Frame ("RadioButton Group");
Label la = new Label ("What shape do you want to draw?:");
fm.setLayout (new GridLayout (0, 1));
CheckboxGroup cg1 = new CheckboxGroup();
fm.add (la);
fm.add (new Checkbox ("CIRCLE", cg1, true));
fm.add (new Checkbox ("SQUARE", cg1, true));
fm.setSize (250, 200);
fm.setVisible (true);
fm.addWindowListener (new WindowAdapter()
{
public void paint (Graphics g) // How can you 'update the drawing' or repaint it?
{
switch (choice) // Maybe for colors if all else fails you can add a switch 'within' a switch. Inefficient-yes but helps.
{
case 1:
if (choice == 1)
g.fillOval (30, 40, 20, 20);
case 2:
if (choice == 2)
g.fillRect (20, 40, 20, 20);
break;
}
}
public void actionPerformed (ActionEvent evt)
{
if (evt.getSource() == "CIRCLE")
choice = 1;
else
choice = 2;
}
public void windowClosing (WindowEvent we)
{
System.exit (0);
}
}
);
}
}
我該如何解決這個問題? – 2013-03-06 00:49:34