[英]error MouseMotionListener, MouseListener
我收到一個錯誤:
AniWorld is not abstract and does not override abstract method mouseMoved(MouseEvent) in MouseMotionListener
public class AniWorld extends Applet implements MouseMotionListener, MouseListener
代碼是:
import java.awt.*;
import java.lang.*;
import java.applet.*;
import java.net.*;
import java.net.MalformedURLException;
import java.applet.Applet.*;
import java.io.IOException;
import java.awt.event.*;
public class AniWorld extends Applet implements MouseMotionListener, MouseListener
{
public Stage stage;
GridBagLayout layout;
public void init()
{
addMouseMotionListener(this);
addMouseListener(this);
setBackground( Color.white );
layout = new GridBagLayout();
setLayout( layout );
int width = Integer.parseInt( getParameter( "width" ).trim() );
int height = Integer.parseInt( getParameter( "height" ).trim() );
stage = new Stage( width-10,height-10);
constrain( stage,this,layout,1,0,1,6,
GridBagConstraints.NONE,
GridBagConstraints.CENTER,0,0 );
stage.addBall();
stage.addRect();
stage.addArc();
stage.start();
}
public void start()
{
stage.start();
} // end of start()
public static void constrain(
Component component,
Container container,
GridBagLayout layout,
int gridx,
int gridy,
int gridwidth,
int gridheight,
int fill,
int anchor,
double weightx,
double weighty
) {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = gridx;
gbc.gridy = gridy;
gbc.gridwidth = gridwidth;
gbc.gridheight = gridheight;
gbc.fill = fill;
gbc.anchor = anchor;
gbc.weightx = weightx;
gbc.weighty = weighty;
layout.setConstraints( component,gbc );
container.add( component );
} // end of constrain()
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
}
不讓您的GUI類實現偵聽器接口的另一個原因。 最好的解決方案不是執行此操作,而是使用擴展MouseAdapter的匿名內部類或執行相同操作的私有內部類。 否則,您會要求您的GUI做太多事情,並為將來可能出現的調試問題做好准備。
您需要添加
public void mouseMoved(MouseEvent)
到AniWorld,或從已實現的接口列表中刪除“ MouseMotionListener”。
出現該錯誤的原因是,當您說實現接口時,必須為接口中的所有方法提供實現,否則您的類需要是抽象的。
因為要實現MouseMotionListener
接口,所以您必須實現(或至少留空實現) MouseDragged(MouseEvent e)
和MouseMoved(MouseEvent e)
。
這里是MouseMotionListener的文檔
是的AniWorld,您必須重寫Interface的所有方法,這意味着如果要實現MouseListener,則必須重寫所有五個方法;如果要保留一個方法來重寫,則100%將會得到相同的錯誤...您正在實現這兩個偵聽器,因此您必須重寫,mouseCliked(),mouseEntered(),mouseExited(),mousePressed(),mouseReleased(),mouseDragged(),mouseMoved()
畢竟方法重寫您將成功而不會出現任何錯誤..
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