javascript - 如何在鼠标点击时设置可拖动事件？

Question

当鼠标左键和右键同时单击并拖动时，我可以设置舞台的可拖动事件吗？

Answer 1

如果您想在按下左右按钮之前阻止拖动，您可以设置形状的 dragBoundFunc 以限制所有拖动，直到您说可以拖动（当您看到两个按钮都按下时）

这是一个关于 dragBoundFunc 的链接：

http://www.html5canvastutorials.com/kineticjs/html5-canvas-drag-and-drop-shapes-horizo​​ntally-or-vertically-tutorial/

以下是一些入门代码：

// add properties to tell whether left/right buttons are currently down

myShape.leftIsDown=false;
myShape.rightIsDown=false;

// add mousedown to set the appropriate button flag to true

myShape.on("mousedown",function(event){
    if(event.button==0){this.leftIsDown=true;}
    if(event.button==2){this.rightIsDown=true;}
});

// add mouseup to set the appropriate button flag to false

myShape.on("mouseup",function(event){
    if(event.button==0){this.leftIsDown=false;}
    if(event.button==2){this.rightIsDown=false;}
});

// add a dragBoundFunc to the shape
// If both buttons are pressed, allow dragging
// If both buttons are not pressed, prevent dragging

dragBoundFunc: function(pos) {
    if(this.leftIsDown && this.rightIsDown){
        // both buttons are down, ok to drag
        return { pos }
    }else{
        // both buttons aren't down, refuse to drag
        return {
          x: this.getAbsolutePosition().x,
          y: this.getAbsolutePosition().y
        }
    }
}