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SYS_Window.addEventListener() method

Add an event listener

Signature

function addEventListener(
	type: ESYS_WindowEventType,
	listener: (ev: any) => any,
	options?: { capture?: boolean; once?: boolean; passive?: boolean; signal?: AbortSignal },
): ISYS_WindowEventListenerRemovableObject | undefined;

Parameters

Parameter	Type	Description
type	ESYS_WindowEventType	Event type, current support blur focus
listener	(ev: any) => any	Event listener callback
options	{ capture?: boolean; once?: boolean; passive?: boolean; signal?: AbortSignal }	(Optional) Optional parameters

Returns

ISYS_WindowEventListenerRemovableObject | undefined

Event listener method, used to remove the event listener. If it is undefined, it means creating the event listener failed

Remarks

监听直接挂载到原生 window 上，返回的可移除对象可传给 SYS_Window.removeEventListener() 移除； 同一扩展重复注册相同 type 的监听会被替换（非累积），卸载扩展时注册的原生监听会被自动清理。

Example

// 示例 1：注册 focus 监听（真实场景由用户切换窗口焦点触发，这里用合成事件模拟）
const removable = eda.sys_Window.addEventListener('focus', () => {
	console.log('窗口获得焦点');
});

// 检查返回的可移除对象，其中的 type 字段记录了监听的事件类型
console.log('监听注册成功：', removable !== undefined, '，事件类型：', removable.type);

// 模拟一次获得焦点事件，回调同步触发
window.dispatchEvent(new Event('focus'));

// 注销监听，恢复原状
eda.sys_Window.removeEventListener(removable);
console.log('监听已注销');