我的一个JComponent
人太激烈地触发了一个mouseDragged
事件。当用户尝试单击时,即使鼠标仅移动了 1 个像素,它也会将其解释为拖动。
我将如何为特定组件添加一条规则,该规则相当于:
不要将其视为拖动事件,除非鼠标已从按下的点移动了 10 个像素。
注意:我知道这不是我操作系统中的系统设置,因为只有该组件上的事件才会受到这种过度敏感的影响。
谢谢你。
我的一个JComponent
人太激烈地触发了一个mouseDragged
事件。当用户尝试单击时,即使鼠标仅移动了 1 个像素,它也会将其解释为拖动。
我将如何为特定组件添加一条规则,该规则相当于:
不要将其视为拖动事件,除非鼠标已从按下的点移动了 10 个像素。
注意:我知道这不是我操作系统中的系统设置,因为只有该组件上的事件才会受到这种过度敏感的影响。
谢谢你。
以前的答案结合在一起,并带有适当的事件类型:
public class DragInsensitiveMouseClickListener implements MouseInputListener {
protected static final int MAX_CLICK_DISTANCE = 15;
private final MouseInputListener target;
public MouseEvent pressed;
public DragInsensitiveMouseClickListener(MouseInputListener target) {
this.target = target;
}
@Override
public final void mousePressed(MouseEvent e) {
pressed = e;
target.mousePressed(e);
}
private int getDragDistance(MouseEvent e) {
int distance = 0;
distance += Math.abs(pressed.getXOnScreen() - e.getXOnScreen());
distance += Math.abs(pressed.getYOnScreen() - e.getYOnScreen());
return distance;
}
@Override
public final void mouseReleased(MouseEvent e) {
target.mouseReleased(e);
if (pressed != null) {
if (getDragDistance(e) < MAX_CLICK_DISTANCE) {
MouseEvent clickEvent = new MouseEvent((Component) pressed.getSource(),
MouseEvent.MOUSE_CLICKED, e.getWhen(), pressed.getModifiers(),
pressed.getX(), pressed.getY(), pressed.getXOnScreen(), pressed.getYOnScreen(),
pressed.getClickCount(), pressed.isPopupTrigger(), pressed.getButton());
target.mouseClicked(clickEvent);
}
pressed = null;
}
}
@Override
public void mouseClicked(MouseEvent e) {
//do nothing, handled by pressed/released handlers
}
@Override
public void mouseEntered(MouseEvent e) {
target.mouseEntered(e);
}
@Override
public void mouseExited(MouseEvent e) {
target.mouseExited(e);
}
@Override
public void mouseDragged(MouseEvent e) {
if (pressed != null) {
if (getDragDistance(e) < MAX_CLICK_DISTANCE) return; //do not trigger drag yet (distance is in "click" perimeter
pressed = null;
}
target.mouseDragged(e);
}
@Override
public void mouseMoved(MouseEvent e) {
target.mouseMoved(e);
}
}
我以前必须这样做。这是我的鼠标事件处理代码,减少到与使拖动相关的位,在被视为拖动之前需要几个像素。
public void mousePressed(int mod, Point loc) {
pressLocation=copyLocation(loc,pressLocation);
dragLocation=null;
}
public void mouseReleased(int mod, Point loc) {
if(pressLocation!=null && dragLocation!=null) {
// Mouse drag reverted to mouse click - not dragged far enough
// action for click
pressLocation=null;
}
else if(dragLocation!=null) {
// action for drag completed
}
else {
// do nothing
}
pressLocation=null;
dragLocation=null;
}
public void mouseDragged(int mod, Point loc) {
if(pressLocation!=null) { // initial drag actions following mouse press
dragLocation=pressLocation; // consider dragging to be from start point
if(Math.abs(loc.x-pressLocation.x)<dragMinimum && Math.abs(loc.y-pressLocation.y)<dragMinimum) {
return; // not dragged far enough to count as drag (yet)
}
// action drag from press location
pressLocation=null;
}
else {
// action drag from last drag location
dragLocation=copyLocation(loc,dragLocation);
}
}
请注意,我也遇到了一些JVM在拖动后生成点击事件的问题,我必须检测和抑制这些事件。
如果我正确阅读了您的问题,则您正在跟踪单击和鼠标拖动事件。您可以在 mousedown 时跟踪坐标,然后在 mousedrag 中进行简短计算以查看鼠标是否已移动所需的最小像素数?当然,您还希望在 mouseup 或鼠标被拖动到 JComponent 边界之外时取消/重置。
警告:我自己没有这样做,但我认为如果是我,我会从这里开始。
Software Monkey 的代码似乎缺少一些代码,所以我写了这个解决方案:
navigationTree.addMouseListener(new DragInsensitiveMouseClickListener(10) {
@Override
public void mouseClicked(MouseEvent e) {
TreePath treePath = navigationTree.getPathForLocation(e.getX(), e.getY());
if(treePath != null) {
processChoice();
}
}
});
当用户产生最多 10 个像素的“拖动行程”时,这仍会触发 mouseClicked() 事件。
点击监听的代码:
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class DragInsensitiveMouseClickListener extends MouseAdapter {
private final int allowedTravel;
public Point mouseDownPoint;
public DragInsensitiveMouseClickListener(int allowedTravel) {
this.allowedTravel = allowedTravel;
}
@Override
public void mousePressed(MouseEvent e) {
mouseDownPoint = e.getPoint();
}
@Override
public void mouseReleased(MouseEvent e) {
double horizontalTravel = Math.abs(mouseDownPoint.getX() - e.getX());
double verticalTravel = Math.abs(mouseDownPoint.getY() - e.getY());
if (horizontalTravel < allowedTravel && verticalTravel < allowedTravel) {
mouseClicked(e);
}
}
}