Question

我创建了一个名为Circle的对象，并且该对象的两个实例名为circle1和circle2我试图让它们交换位置，但只有其中一个正在移动那一刻。

使用Javascript：

var gap = 6, size= 60;
var Circle = function(t,l, color){
        var elem = document.createElement('div');
        t = t,
        l = l;

        elem.setAttribute("class", "circle");
        elem.style.backgroundColor = color;

        // init positions
        elem.style.top  = gap+t*(size+2*gap) + "px";
        elem.style.left = gap+l*(size+2*gap) + "px";
        document.body.appendChild(elem);

        this.getPosition = function(){
            return [t,l];
        };

        this.setPosition = function(arr){
            t = arr[0];
            l = arr[1];
            elem.style.top  = gap+t*(size+2*gap) + "px";
            elem.style.left = gap+l*(size+2*gap) + "px";
        };
}

// make two new circle objects 
var circle1 = new Circle(0, 0, "blue");
var circle2 = new Circle(0, 1, "red");

// we need the circles to swap positions
setTimeout(function(){
    circle1.setPosition(circle2.getPosition());
    circle2.setPosition(circle1.getPosition()); // this is not working
}, 1000);

我已将此代码放在jsFiddle上以使其更容易： http://jsfiddle.net/rhL7671p/

Answer 1

只需缓存第一个圆圈的位置：

setTimeout(function(){
   var pos = circle1.getPosition();
   circle1.setPosition( circle2.getPosition() );
   circle2.setPosition( pos );
}, 1000);

Example Fiddle

在此行之后的代码中

circle1.setPosition(circle2.getPosition());

第一个圆圈的位置被第二个圆圈的位置覆盖。因此下一行没有效果。在JavaScript中没有并行执行代码的事情，因为只有一个线程（有一些例外......）。

规避这个问题：首先获得一个（或两个）位置，然后再设置它们。

Answer 2

在更新位置之前存储左圆圈的位置。

setTimeout(function(){
    var c = circle1.getPosition();
    circle1.setPosition(circle2.getPosition());
    circle2.setPosition(c);
}, 1000);

var gap = 6, size= 60;
var Circle = function(t,l, color){
		var elem = document.createElement('div');
        t = t,
        l = l;
    
        elem.setAttribute("class", "circle");
        elem.style.backgroundColor = color;
        elem.style.top  = gap+t*(size+2*gap) + "px";
        elem.style.left = gap+l*(size+2*gap) + "px";
        document.body.appendChild(elem);

        this.getPosition = function(){
        	return [t,l];
        }

        this.setPosition = function(arr){
        	t = arr[0];
            l = arr[1];
        	elem.style.top  = gap+t*(size+2*gap) + "px";
        	elem.style.left = gap+l*(size+2*gap) + "px";
    	}

       	
	}

var circle1 = new Circle(0,0, "blue");
var circle2 = new Circle(0,1, "red");

// we need the circles to swap positions
setTimeout(function(){
    var c = circle1.getPosition();
    circle1.setPosition(circle2.getPosition());
    circle2.setPosition(c);
}, 1000);

console.log(circle2)

.circle{
    width:60px;
    height:60px;
    border-radius: 50px;
    background-color:red;
    position:absolute;
    -webkit-transition-property: top, left;
        -webkit-transition-duration: 0.3s;
}

Answer 3

getPosition的结果不是您在移动第一个圆圈后所期望的，所以在移动之前将其缓存

setTimeout(function(){
    var a = circle2.getPosition(),
        b = circle1.getPosition();
    circle1.setPosition(a);
    circle2.setPosition(b);
}, 1000);

Answer 4

这种情况正在发生，因为当您尝试获取元素的位置时会有新值。一种可能的解决方案是使用局部变量：

＆＃13;

var gap = 6,
  size = 60;
var Circle = function(t, l, color) {
  var elem = document.createElement('div');
  t = t,
    l = l;

  elem.setAttribute("class", "circle");
  elem.style.backgroundColor = color;
  elem.style.top = gap + t * (size + 2 * gap) + "px";
  elem.style.left = gap + l * (size + 2 * gap) + "px";
  document.body.appendChild(elem);

  this.getPosition = function() {
    return [t, l];
  }

  this.setPosition = function(arr) {
    t = arr[0];
    l = arr[1];
    elem.style.top = gap + t * (size + 2 * gap) + "px";
    elem.style.left = gap + l * (size + 2 * gap) + "px";
  }


}

var circle1 = new Circle(0, 0, "blue");
var circle2 = new Circle(0, 1, "red");

// we need the circles to swap positions
setTimeout(function() {
  //use local variables to keep circles position
  var circle1Pos = circle1.getPosition();
  var circle2Pos = circle2.getPosition()
  circle1.setPosition(circle2Pos);
  circle2.setPosition(circle1Pos);
}, 200);

＆＃13;

.circle {
  width: 60px;
  height: 60px;
  border-radius: 50px;
  background-color: red;
  position: absolute;
  -webkit-transition-property: top, left;
  -webkit-transition-duration: 0.3s;
}

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

＆＃13;

如何使用javascript移动多个DOM元素？

4 个答案: