我如何设置这个 removeEventListener 的参数？

Question

I was about to make some rotation programm (worked by mouse click & drag) but the 'removeEventListener' doesn't work.我正要制作一些旋转程序（通过鼠标单击和拖动来工作）但是“removeEventListener”不起作用。 can u explain me how to work it and why doesn't it work?你能解释一下它是如何工作的吗？为什么它不起作用？

And this is my first question in here so if u find any problems about this question, I'll gladly accept it.这是我在这里的第一个问题，所以如果你发现这个问题有任何问题，我会很乐意接受。

<body>

    <div class="wrap">

        <div class="target">target</div>

    </div>
</body>

const html = document.querySelector("html");
const info = document.querySelector(".info");

const target = document.querySelector(".target");
const wrap = document.querySelector(".wrap");
let center = {
  x: target.getBoundingClientRect().left + target.clientWidth / 2,
  y: target.getBoundingClientRect().top + target.clientHeight / 2,
};

window.addEventListener("resize", () => {
  center = {
    x: target.getBoundingClientRect().left + target.clientWidth / 2,
    y: target.getBoundingClientRect().top + target.clientHeight / 2,
  };
});

const rotate = function () {
  target.addEventListener("mousemove", (e) => {
    const x = center.x - e.clientX;
    const y = center.y - e.clientY;

    const radian = Math.atan2(y, x);
    const degree = ((radian * 180) / Math.PI).toFixed(0);
    target.style.transform = "rotate(" + degree + "deg)";
  });
};

target.addEventListener("mousedown", rotate, true);

target.addEventListener("mouseup", () => {
  target.removeEventListener("mousedown", rotate, false);

});

I've tried to change this part.我试图改变这部分。 target -> wrap and removeEventListener's param to another one. target -> 包装和 removeEventListener 的参数到另一个。 But none of those worked但这些都不起作用

target.addEventListener("mouseup", () => {
  target.removeEventListener("mousedown", rotate, false);
});

Answer 1

The capture/ use capture falg must match to remove listener.捕获/使用捕获标志必须匹配才能删除侦听器。 Since you used true for your mousedown even listener you also must use true to remove event listener:由于您对mousedown甚至侦听器使用了 true ，因此您还必须使用 true 来删除事件侦听器：

target.addEventListener("mouseup", () => {
    target.removeEventListener("mousedown", rotate, true);
});

See docs for more details: https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener#matching_event_listeners_for_removal有关详细信息，请参阅文档： https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener#matching_event_listeners_for_removal

我如何设置这个 removeEventListener 的参数？

问题描述

1 个解决方案

解决方案1
0 已采纳 2023-01-12 03:13:44

我如何设置这个 removeEventListener 的参数？

问题描述

1 个解决方案

解决方案1 0 已采纳 2023-01-12 03:13:44

解决方案1
0 已采纳 2023-01-12 03:13:44