Java 中的 MouseListener 和 MouseMotionListener
哎哎哎:# t0]https://www . geeksforgeeks . org/mouelistener-mouemotionlistener-Java/
MouseListener 和 MouseMotionListener 是 java.awt.event 包中的一个接口。鼠标事件 有两种类型。当鼠标不运动时，鼠标监听器处理事件。而鼠标运动监听器 处理鼠标运动时的事件。【MouseListener 可以生成五种类型的事件。有五个抽象函数表示这五个事件。抽象功能有:
- void Mouse released(Mouse event e):鼠标键释放
- void Mouse clicked(Mouse event e):鼠标键被按下/释放
- 无效鼠标退出(MouseEvent e) :鼠标退出组件
- 无效鼠标进入(MouseEvent e) :鼠标进入组件
- void Mouse pressed(Mouse event e):鼠标键被按下
MouseMotionListener 可以生成两种类型的事件。有两个抽象函数表示这五个事件。抽象函数有:
- void MouseDrawed(MouseEvent e):在组件中按下鼠标按钮并拖动时调用。事件被传递，直到用户释放鼠标按钮。
- void mouse moved(mouse event e):当鼠标光标在组件内从一个点移动到另一个点时调用，无需按任何鼠标按钮。
下面的程序演示了鼠标监听器和鼠标移动监听器。 1。处理鼠标监听器事件的程序
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to handle MouseListener events
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Mouse extends Frame implements MouseListener {
// Jlabels to display the actions of events of mouseListener
// static JLabel label1, label2, label3;
// default constructor
Mouse()
{
}
// main class
public static void main(String[] args)
{
// create a frame
JFrame f = new JFrame("MouseListener");
// set the size of the frame
f.setSize(600, 100);
// close the frame when close button is pressed
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// create anew panel
JPanel p = new JPanel();
// set the layout of the panel
p.setLayout(new FlowLayout());
// initialize the labels
label1 = new JLabel("no event ");
label2 = new JLabel("no event ");
label3 = new JLabel("no event ");
// create an object of mouse class
Mouse m = new Mouse();
// add mouseListener to the frame
f.addMouseListener(m);
// add labels to the panel
p.add(label1);
p.add(label2);
p.add(label3);
// add panel to the frame
f.add(p);
f.show();
}
// getX() and getY() functions return the
// x and y coordinates of the current
// mouse position
// getClickCount() returns the number of
// quick consecutive clicks made by the user
// this function is invoked when the mouse is pressed
public void mousePressed(MouseEvent e)
{
// show the point where the user pressed the mouse
label1.setText("mouse pressed at point:"
+ e.getX() + " " + e.getY());
}
// this function is invoked when the mouse is released
public void mouseReleased(MouseEvent e)
{
// show the point where the user released the mouse click
label1.setText("mouse released at point:"
+ e.getX() + " " + e.getY());
}
// this function is invoked when the mouse exits the component
public void mouseExited(MouseEvent e)
{
// show the point through which the mouse exited the frame
label2.setText("mouse exited through point:"
+ e.getX() + " " + e.getY());
}
// this function is invoked when the mouse enters the component
public void mouseEntered(MouseEvent e)
{
// show the point through which the mouse entered the frame
label2.setText("mouse entered at point:"
+ e.getX() + " " + e.getY());
}
// this function is invoked when the mouse is pressed or released
public void mouseClicked(MouseEvent e)
{
// getClickCount gives the number of quick,
// consecutive clicks made by the user
// show the point where the mouse is i.e
// the x and y coordinates
label3.setText("mouse clicked at point:"
+ e.getX() + " "
+ e.getY() + "mouse clicked :" + e.getClickCount());
}
}
输出:
注意:以下程序可能无法在在线编译器中运行请使用离线 IDE 让我们在 MouseListener 上再举一个例子，问题是: Q. 编写一个小程序，每当用户在小程序窗口中的任何地方单击时，它都会在其状态栏中显示 x 和 y 坐标。 Ans。 注意:此代码是关于 Netbeans IDE 的。
Java 语言(一种计算机语言，尤用于创建网站)
//Program of an applet which
//displays x and y co-ordinate
//in it's status bar,whenever
//the user click anywhere in
//the applet window.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class GFG extends Applet implements MouseListener
{
public void init()
{
this.addMouseListener (this);
//first "this" represent source
//(in this case it is applet which
//is current calling object) and
//second "this" represent
//listener(in this case it is GFG)
}
public void mouseClicked(MouseEvent m)
{
int x = m.getX();
int y = m.getY();
String str = "x =" +x+",y = "+y;
showStatus(str);
}
@Override
public void mousePressed(MouseEvent e) {
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
}
@Override
public void mouseExited(MouseEvent e) {
}
}
输出:
状态栏中显示(x，y)的输出
修改:现在我们的目标是改进上述程序，以便坐标只显示在点击的地方 注意:该代码与 Netbeans IDE 相关。
Java 语言(一种计算机语言，尤用于创建网站)
//Co-ordinates should display
//at that point only wherever
//their is click on canvas
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class GFG extends Applet implements MouseListener
{
private int x,y;
private String str = " ";
public void init()
{
this.addMouseListener (this);
//first "this" represent source
//(in this case it is applet which
// is current calling object) and
// second "this" represent listener
//(in this case it is GFG)
}
public void paint(Graphics g)
{
g.drawString(str,x,y);
}
public void mouseClicked(MouseEvent m)
{
x = m.getX();
y = m.getY();
str = "x =" +x+",y = "+y;
repaint(); // we have made this
//call because repaint() will
//call paint() method for us.
//If we comment out this line,
//then we will see output
//only when focus is on the applet
//i.e on maximising the applet window
//because paint() method is called
//when applet screen gets the focus.
//repaint() is a method of Component
//class and prototype for this method is:
//public void repaint()
}
public void mouseEntered(MouseEvent m)
//over-riding all the methods given by
// MouseListener
{
}
public void mouseExited(MouseEvent m)
{
}
public void mousePressed(MouseEvent m)
{
}
public void mouseReleased(MouseEvent m)
{
}
}
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