这个问题与RXJS有关。我正在尝试调整github中的拖放示例,以便为一类div而不仅仅是单个元素ID。 https://github.com/Reactive-Extensions/RxJS/blob/master/examples/dragndrop/dragndrop.html
简单的更改为div提供类或ID不起作用,我失去了拖动元素的能力
3个简单的改变:
HTML line 7 i.e. <div class="dragTarget">Drag Me!</div>
CSS line 1 i.e. .dragTarget { style attributes unchanged }
JS line 4 i.e var dragTarget = document.getElementsByClassName('dragTarget');
我不熟练知道这是否是RXJS中的错误,或者该示例不够通用。有关RXJS事件的文件表明这些变化应该足够了。任何帮助赞赏。感谢。
答案 0 :(得分:4)
fromEvent
将使用您传递的任何对象的on
和off
方法,否则将使用addEventListener
和removeEventListener
。因此,如果你正在使用jQuery,你可以简单地选择所有这些并使用它(例如Observable.fromEvent($('.targetNode'), 'mouseup')
)。
否则,您可以使用on
和off
方法的任何对象订阅或取消订阅活动,例如我在下面做的。
除此之外,您可以在每个流中获得的target
个对象上使用MouseEvent
属性来获取您想要移动的实际DOM节点...
下面的示例应该可以解决这个问题。
(function (global) {
/**
selectNodes is a method to select a NodeList, but convert it to
a type that has `on` and `off` methods RxJS 2 expects to see for `fromEvent`
*/
function selectNodes(selector) {
var nodes = document.querySelectorAll(selector);
return {
// the selected nodes
nodes: [].slice.call(this.nodes),
// subscribe to an event on every selected node
on: function(eventName, handler) {
this.nodes.forEach(function(node) { node.addEventListener(eventName, handler); });
},
// unsubscribe from the event on every selected node
off: function(eventName, handler) {
this.nodes.forEach(function(node) { node.removeEventListener(eventName, handler); });
}
};
}
function main () {
// IMPORTANT CHANGE: Use the selectNodes method we made
var dragTargets = selectNodes('.dragTarget');
// Get the three major events
var mouseup = Rx.Observable.fromEvent(dragTargets, 'mouseup');
var mousemove = Rx.Observable.fromEvent(document, 'mousemove');
var mousedown = Rx.Observable.fromEvent(dragTargets, 'mousedown');
var mousedrag = mousedown.flatMap(function (md) {
// calculate offsets when mouse down
var startX = md.offsetX, startY = md.offsetY;
// Calculate delta with mousemove until mouseup
return mousemove.map(function (mm) {
mm.preventDefault();
return {
left: mm.clientX - startX,
top: mm.clientY - startY,
target: mm.target, // IMPORTANT CHANGE: the element you care about
};
}).takeUntil(mouseup);
});
// Update position
var subscription = mousedrag.subscribe(function (d) {
d.target.style.top = d.top + 'px';
d.target.style.left = d.left + 'px';
});
}
main();
}(window));