在 google 关闭中使用 unlistenByKey 监听事件

Question

goog.events 提供了 unlistenByKey 方法，允许特定取消注册听众以其独特的身份。获取此密钥的唯一方法是通过侦听每种事件类型再次调用 goog.events.listen 或使用以下命令调用 goog.events.getListener ，这是否正确监听的每种事件类型？

例如

var eventKeys = new Array(2);
goog.events.listen(document, ['mousedown', 'touchstart'], this.pressStartHandler_, false, this);
eventKey[0] = goog.events.getListener(document, 'mousedown', this.pressStartHandler_, false, this);
eventKey[1] = goog.events.getListener(document, 'touchstart', this.pressStartHandler_, false, this);    

编辑

除非回答者提供更好的建议，否则我编写了以下包装器来获取密钥：

/**
 * Wrap goog.events.listen to capture all of the event keys of the requested listeners.
 * 
 * @param {(EventTarget |
 *          goog.events.EventTarget | null)} src The node to listen to events on.
 * @param {(Array |
 *          null | string)} type Event type or array of event types.
 * @param {(Object |
 *          null)} listener Callback method, or an object with a handleEvent function.
 * @param {(boolean |
 *          undefined)} opt_capt Whether to fire in capture phase (defaults to false).
 * @param {(Object |
 *          null | undefined)} opt_handler Element in whose scope to call the listener.
 * @returns {Array.<number>} Array of keys for listeners
 */
wias.util.listen = function(src, type, listener, opt_capt, opt_handler)
{
  var i;
  var keys = new Array();
  goog.events.listen(src, type, listener, opt_capt, opt_handler);
  if (type instanceof Array)
  {
    for (i = 0; i < type.length; i++)
    {
      keys.push(goog.events.getListener(src, type[i], listener, opt_capt, opt_handler).key);
    }
  }
  else
  {
    keys.push(goog.events.getListener(src, type, listener, opt_capt, opt_handler).key);
  }
  return keys;
};

Answer 1

您可能会发现 goog.events.EventHandler 很有用。

// Note that all handler callbacks receive 'this' as the opt_handler, by default.
var handler = new goog.events.EventHandler(this);
handler.listen(
    document, ['mousedown', 'touchstart'], this.pressStartHandler_, false);

// Some time later...
handler.removeAll();

为了回答最初的问题，goog.events.listen 在与单个事件类型一起使用时也会返回键。通过迭代每个事件类型，为每个事件类型调用 goog.events.listen 并存储每个事件的密钥，您可以在上述实现中稍微更正确和简洁。

wias.util.listen = function(src, type, listener, opt_capt, opt_handler) {
  var keys = new Array();
  if (type instanceof Array) {
    for (var i = 0; i < type.length; i++) {
      keys.push(goog.events.listen(src, type, listener, opt_capt, opt_handler));
    }
  } else {
    keys.push(goog.events.listen(src, type, listener, opt_capt, opt_handler));
  }
  return keys;
};