我想在JLabel中检测鼠标点击事件，其方式类似于可用于JButton的“ActionListener.actionPerformed（）”功能。
我该怎么做？其他细节如下。
MouseAdapter类的功能与可用于JButton的ActionListener功能不同。如果鼠标指针在mousePressed和mouseReleased事件之间移动（甚至稍微），MouseAdapter.mouseClicked（）函数将不会注册鼠标点击，这使得界面有时“错过”预期的点击。
或者，MouseAdapter.mousePressed（）事件可以检测所有点击，但在这种情况下，每次点击都会在释放鼠标按钮之前注册。 （这可能是某些用户的意外行为。）
在JButton ActionListener.actionPerformed（）事件中，即使按下鼠标按钮，移动指针，然后释放鼠标按钮，也会注册鼠标。 （只要指针不离开JButton边界，就是这样）。我想知道如何通过单击和/或双击JLabel来实现这种更强大的点击检测行为？
谢谢。
答案 0 :(得分：1)
您描述的“强大点击”功能可以使用自定义MouseAdapter类来完成。下面粘贴的是我编写的MouseLiberalAdapter类的副本，用于在JLabel（或其他swing组件）中正确捕获“移动”鼠标单击事件。
使用MouseLiberalAdapter类的说明：
使用示例：
JLabel labelSingleClick = new JLabel("Single click me.");
JLabel labelDoubleClick = new JLabel("Double click me.");
labelSingleClick.addMouseListener(new MouseLiberalAdapter() {
@Override
public void mouseLiberalClick(MouseEvent e) {
JOptionPane.showMessageDialog(null, "Single click detected.");
}
});
labelDoubleClick.addMouseListener(new MouseLiberalAdapter() {
@Override
public void mouseLiberalDoubleClick(MouseEvent e) {
JOptionPane.showMessageDialog(null, "Double click detected.");
}
});
MouseLiberalAdapter类：
package com.project.utilities;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelEvent;
/**
* MouseLiberalAdapter.
*
* This class extends the MouseAdapter class, to include two additional events. The added events are
* the mouseLiberalClick() and the mouseLiberalDoubleClick(). By default, the mouseClick() event in
* the MouseAdapter has a limitation. The mouseClick() event cannot register a click if the mouse
* pointer moves even slightly, between the mouse press and mouse release events. By contrast, the
* mouseLiberalClick() will register a "liberal mouse click" even if the mouse moves (by any amount)
* during the click event, as long as the mouse pointer does not leave the boundaries of the
* component which is generating the mouse events. (This "liberal mouse click" behavior duplicates
* the "actionPerformed()" functionality that exists in the JButton class.)
*
* Note: This class is frequently used to detect clicks in a JLabel, but it can be used in any swing
* component that will accept a MouseAdapter.
*
* Using this class is similar to using the MouseAdapter class. (See also: The MouseAdapter
* javadocs.) To use this class, you would extend this class and override any (non-final) event
* methods that are of interest.
*
* The original MouseAdapter functions have been marked as final, and cannot be overridden. However,
* the class still provides all the original functions (with slightly modified function names). The
* two new functions are also provided: mouseLiberalClick() and mouseLiberalDoubleClick(). A usage
* example is shown below.
*
* Usage example:
* <pre> {@code
* JLabel labelSingleClick = new JLabel("Single click me.");
* JLabel labelDoubleClick = new JLabel("Double click me.");
* labelSingleClick.addMouseListener(new MouseLiberalAdapter() {
* @Override
* public void mouseLiberalClick(MouseEvent e) {
* JOptionPane.showMessageDialog(null, "Single click detected.");
* }
* });
* labelDoubleClick.addMouseListener(new MouseLiberalAdapter() {
* @Override
* public void mouseLiberalDoubleClick(MouseEvent e) {
* JOptionPane.showMessageDialog(null, "Double click detected.");
* }
* });
* }</pre>
*/
public abstract class MouseLiberalAdapter extends MouseAdapter {
/**
* isComponentPressedDown, This indicates whether or not the component is currently
* (conceptually) "pressed down". To understand the meaning of "pressed down", consider the
* behavior of a JButton. When you press the mouse inside a button, the button redraws itself to
* indicate a "press down" state. If you release the mouse while inside the button, a button
* click will be registered, and the button will switch to a "not press down" state. The button
* can also become "not pressed down" if the mouse pointer leaves the boundaries of the button
* without first releasing the mouse.
*/
private boolean isComponentPressedDown = false;
/**
* lastUnusedLiberalSingleClickTimeStamp, This stores a timestamp for the mouse release of the
* last unused liberal single click. If a single click is "used" as part of a double click, then
* it's timestamp will no longer be stored here. If there is no liberal single click which fits
* the above description, then this will contain the value zero.
*/
private long lastUnusedLiberalSingleClickTimeStamp = 0;
/**
* slowestDoubleClickMilliseconds, This constant indicates the maximum time window in which a
* liberal double click can occur. More specifically, this indicates the maximum time, in
* milliseconds, between liberal single click mouse releases, that will be considered to
* constitute a liberal double click.
*/
private final int slowestDoubleClickMilliseconds = 1800;
/**
* mouseLiberalClick, Override this function to catch liberal single click events.
*
* Note: The mouse event which is passed to this function will be the mouse event that was
* received from the "mouseRelease" event at the end of the liberal single click.
*/
public void mouseLiberalClick(MouseEvent e) {
}
/**
* mouseLiberalDoubleClick, Override this function to catch liberal double click events.
*
* Note: The mouse event which is passed to this function will be the mouse event that was
* received from the "mouseRelease" event at the end of the liberal double click.
*/
public void mouseLiberalDoubleClick(MouseEvent e) {
}
/**
* mouseClick, Override this function to catch standard mouse click events.
*/
public void mouseClick(MouseEvent e) {
}
/**
* mousePress, Override this function to catch standard mouse press events.
*/
public void mousePress(MouseEvent e) {
}
/**
* mouseRelease, Override this function to catch standard mouse release events.
*/
public void mouseRelease(MouseEvent e) {
}
/**
* mouseEnter, Override this function to catch standard mouse enter events.
*/
public void mouseEnter(MouseEvent e) {
}
/**
* mouseExit, Override this function to catch standard mouse exit events.
*/
public void mouseExit(MouseEvent e) {
}
/**
* mouseWheelMove, Override this function to catch standard mouse wheel move events.
*/
public void mouseWheelMove(MouseWheelEvent e) {
}
/**
* mouseDrag, Override this function to catch standard mouse drag events.
*/
public void mouseDrag(MouseEvent e) {
}
/**
* mouseMove, Override this function to catch standard mouse move events.
*/
public void mouseMove(MouseEvent e) {
}
/**
* mousePressed, Final function. Handles mouse pressed events.
*/
@Override
final public void mousePressed(MouseEvent e) {
// Record that the component is "pressed down".
isComponentPressedDown = true;
// Call the mouse press event.
mousePress(e);
}
/**
* mouseReleased, Final function. Handles mouse released events. This function also detects
* liberal single clicks, and liberal double clicks.
*/
@Override
final public void mouseReleased(MouseEvent e) {
// Check to see if this mouse release completes a liberal single click.
if (isComponentPressedDown) {
// A liberal single click has occurred.
mouseLiberalClick(e);
// Check to see if we had two liberal single clicks within the double click time window.
long now = System.currentTimeMillis();
long timeBetweenUnusedClicks = now - lastUnusedLiberalSingleClickTimeStamp;
if (timeBetweenUnusedClicks <= slowestDoubleClickMilliseconds) {
// A liberal double click has occurred.
mouseLiberalDoubleClick(e);
// Mark the single click timestamp as "used" by this double click.
lastUnusedLiberalSingleClickTimeStamp = 0;
} else {
// Save the single click timestamp as part of a possible future double click.
lastUnusedLiberalSingleClickTimeStamp = System.currentTimeMillis();
}
}
// Record the mouse release.
isComponentPressedDown = false;
// Call the mouse release event.
mouseRelease(e);
}
/**
* mouseEntered, Final function. Handles mouse entered events.
*/
@Override
final public void mouseEntered(MouseEvent e) {
// Call the mouse enter event.
mouseEnter(e);
}
/**
* mouseExited, Final function. Handles mouse exited events.
*/
@Override
final public void mouseExited(MouseEvent e) {
// Since the mouse left the component, the component is no longer considered "press down".
isComponentPressedDown = false;
// Call the mouse exit event.
mouseExit(e);
}
/**
* mouseClicked, Final function. Handles mouse clicked events.
*/
@Override
final public void mouseClicked(MouseEvent e) {
// Call the mouse click event.
mouseClick(e);
}
/**
* mouseWheelMoved, Final function. Handles mouse wheel moved events.
*/
@Override
final public void mouseWheelMoved(MouseWheelEvent e) {
// Call the mouse wheel move event.
mouseWheelMove(e);
}
/**
* mouseDragged, Final function. Handles mouse dragged events.
*/
@Override
final public void mouseDragged(MouseEvent e) {
// Call the mouse drag event.
mouseDrag(e);
}
/**
* mouseMoved, Final function. Handles mouse moved events.
*/
@Override
final public void mouseMoved(MouseEvent e) {
// Call the mouse move event.
mouseMove(e);
}
}