$(window).resize(function() { ... });
然而,如果用户通过拖动窗口边缘手动调整浏览器窗口的大小,则上述.resize
事件会多次触发。
问题:如何在浏览器窗口调整大小完成后调用函数(以便事件仅触发一次)?
$(window).resize(function() { ... });
然而,如果用户通过拖动窗口边缘手动调整浏览器窗口的大小,则上述.resize
事件会多次触发。
问题:如何在浏览器窗口调整大小完成后调用函数(以便事件仅触发一次)?
var waitForFinalEvent = (function () {
var timers = {};
return function (callback, ms, uniqueId) {
if (!uniqueId) {
uniqueId = "Don't call this twice without a uniqueId";
}
if (timers[uniqueId]) {
clearTimeout (timers[uniqueId]);
}
timers[uniqueId] = setTimeout(callback, ms);
};
})();
使用方法:
$(window).resize(function () {
waitForFinalEvent(function(){
alert('Resize...');
//...
}, 500, "some unique string");
});
如果您只调用一次CMS的解决方案,那么它是可以的,但是如果您多次调用它,例如,如果您的代码的不同部分设置了单独的回调以调整窗口大小,则它将失败,因为它们共享计时器
变量。
通过这种修改,您可以为每个回调提供一个唯一的ID,并使用这些唯一的ID来保持所有超时事件分开。
timers
不是全局的,对吧? - galingong$(window).bind('resizeEnd', function() {
//do something, window hasn't changed size in 500ms
});
以下是创建它的方法:
$(window).resize(function() {
if(this.resizeTO) clearTimeout(this.resizeTO);
this.resizeTO = setTimeout(function() {
$(this).trigger('resizeEnd');
}, 500);
});
我使用以下函数来延迟重复的操作,它适用于您的情况:
var delay = (function(){
var timer = 0;
return function(callback, ms){
clearTimeout (timer);
timer = setTimeout(callback, ms);
};
})();
使用方法:
$(window).resize(function() {
delay(function(){
alert('Resize...');
//...
}, 500);
});
传递给它的回调函数只会在经过指定时间后执行最后一次delay调用之后,否则计时器将被重置。我发现这对于其他用途非常有用,例如检测用户停止输入等...
$(window).resize
),则我认为此方法可能会失败,因为它们将共享“timer”变量。请参见下面我的答案,以获取建议的解决方案。 - brahn如果您已安装Underscore.js,您可以:
$(window).resize(_.debounce(function(){
alert("Resized");
},500));
之前提到的某些解决方案对我不起作用,尽管它们具有更广泛的使用。相反,我在窗口调整大小时找到了这个解决方案:
$(window).bind('resize', function(e){
window.resizeEvt;
$(window).resize(function(){
clearTimeout(window.resizeEvt);
window.resizeEvt = setTimeout(function(){
//code to do after window is resized
}, 250);
});
});
非常感谢 David Walsh,这里是一个纯净版的 underscore debounce 函数。
代码:
// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds. If `immediate` is passed, trigger the function on the
// leading edge, instead of the trailing.
function debounce(func, wait, immediate) {
var timeout;
return function() {
var context = this, args = arguments;
var later = function() {
timeout = null;
if (!immediate) func.apply(context, args);
};
var callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) func.apply(context, args);
};
};
简单使用:
var myEfficientFn = debounce(function() {
// All the taxing stuff you do
}, 250);
$(window).on('resize', myEfficientFn);
声明全局延迟监听器:
var resize_timeout;
$(window).on('resize orientationchange', function(){
clearTimeout(resize_timeout);
resize_timeout = setTimeout(function(){
$(window).trigger('resized');
}, 250);
});
下面使用监听器来处理resized
事件,你可以根据自己的需要进行处理:
$(window).on('resized', function(){
console.log('resized');
});
这对我有用。 请参考这个解决方案:https://alvarotrigo.com/blog/firing-resize-event-only-once-when-resizing-is-finished/
var resizeId;
$(window).resize(function() {
clearTimeout(resizeId);
resizeId = setTimeout(doneResizing, 500);
});
function doneResizing(){
//whatever we want to do
}
实际上,据我所知,当调整大小关闭时,您确切地无法执行某些操作,这仅是因为您不知道未来用户的操作。但是,您可以假设两个调整大小事件之间经过的时间,因此,如果您等待的时间比此时间长一点,并且没有进行调整大小,则可以调用您的函数。
想法是我们使用setTimeout
及其id来保存或删除它。例如,我们知道两个调整大小事件之间的时间为500ms,因此我们将等待750ms。
var a;
$(window).resize(function(){
clearTimeout(a);
a = setTimeout(function(){
// call your function
},750);
});
这是一个针对延迟窗口大小调整事件的简单 jQuery 插件。
为调整事件添加新函数
jQuery(window).resizeDelayed( func, delay, id ); // delay and id are optional
通过声明其ID,删除先前添加的功能
jQuery(window).resizeDelayed( false, id );
jQuery(window).resizeDelayed( false );
// ADD SOME FUNCTIONS TO RESIZE EVENT
jQuery(window).resizeDelayed( function(){ console.log( 'first event - should run after 0.4 seconds'); }, 400, 'id-first-event' );
jQuery(window).resizeDelayed( function(){ console.log('second event - should run after 1.5 seconds'); }, 1500, 'id-second-event' );
jQuery(window).resizeDelayed( function(){ console.log( 'third event - should run after 3.0 seconds'); }, 3000, 'id-third-event' );
// LETS DELETE THE SECOND ONE
jQuery(window).resizeDelayed( false, 'id-second-event' );
// LETS ADD ONE WITH AUTOGENERATED ID(THIS COULDNT BE DELETED LATER) AND DEFAULT TIMEOUT (500ms)
jQuery(window).resizeDelayed( function(){ console.log('newest event - should run after 0.5 second'); } );
// LETS CALL RESIZE EVENT MANUALLY MULTIPLE TIMES (OR YOU CAN RESIZE YOUR BROWSER WINDOW) TO SEE WHAT WILL HAPPEN
jQuery(window).resize().resize().resize().resize().resize().resize().resize();
使用输出:
first event - should run after 0.4 seconds
newest event - should run after 0.5 second
third event - should run after 3.0 seconds
jQuery.fn.resizeDelayed = (function(){
// >>> THIS PART RUNS ONLY ONCE - RIGHT NOW
var rd_funcs = [], rd_counter = 1, foreachResizeFunction = function( func ){ for( var index in rd_funcs ) { func(index); } };
// REGISTER JQUERY RESIZE EVENT HANDLER
jQuery(window).resize(function() {
// SET/RESET TIMEOUT ON EACH REGISTERED FUNCTION
foreachResizeFunction(function(index){
// IF THIS FUNCTION IS MANUALLY DISABLED ( by calling jQuery(window).resizeDelayed(false, 'id') ),
// THEN JUST CONTINUE TO NEXT ONE
if( rd_funcs[index] === false )
return; // CONTINUE;
// IF setTimeout IS ALREADY SET, THAT MEANS THAT WE SHOULD RESET IT BECAUSE ITS CALLED BEFORE DURATION TIME EXPIRES
if( rd_funcs[index].timeout !== false )
clearTimeout( rd_funcs[index].timeout );
// SET NEW TIMEOUT BY RESPECTING DURATION TIME
rd_funcs[index].timeout = setTimeout( rd_funcs[index].func, rd_funcs[index].delay );
});
});
// <<< THIS PART RUNS ONLY ONCE - RIGHT NOW
// RETURN THE FUNCTION WHICH JQUERY SHOULD USE WHEN jQuery(window).resizeDelayed(...) IS CALLED
return function( func_or_false, delay_or_id, id ){
// FIRST PARAM SHOULD BE SET!
if( typeof func_or_false == "undefined" ){
console.log( 'jQuery(window).resizeDelayed(...) REQUIRES AT LEAST 1 PARAMETER!' );
return this; // RETURN JQUERY OBJECT
}
// SHOULD WE DELETE THE EXISTING FUNCTION(S) INSTEAD OF CREATING A NEW ONE?
if( func_or_false == false ){
// DELETE ALL REGISTERED FUNCTIONS?
if( typeof delay_or_id == "undefined" ){
// CLEAR ALL setTimeout's FIRST
foreachResizeFunction(function(index){
if( typeof rd_funcs[index] != "undefined" && rd_funcs[index].timeout !== false )
clearTimeout( rd_funcs[index].timeout );
});
rd_funcs = [];
return this; // RETURN JQUERY OBJECT
}
// DELETE ONLY THE FUNCTION WITH SPECIFIC ID?
else if( typeof rd_funcs[delay_or_id] != "undefined" ){
// CLEAR setTimeout FIRST
if( rd_funcs[delay_or_id].timeout !== false )
clearTimeout( rd_funcs[delay_or_id].timeout );
rd_funcs[delay_or_id] = false;
return this; // RETURN JQUERY OBJECT
}
}
// NOW, FIRST PARAM MUST BE THE FUNCTION
if( typeof func_or_false != "function" )
return this; // RETURN JQUERY OBJECT
// SET THE DEFAULT DELAY TIME IF ITS NOT ALREADY SET
if( typeof delay_or_id == "undefined" || isNaN(delay_or_id) )
delay_or_id = 500;
// SET THE DEFAULT ID IF ITS NOT ALREADY SET
if( typeof id == "undefined" )
id = rd_counter;
// ADD NEW FUNCTION TO RESIZE EVENT
rd_funcs[id] = {
func : func_or_false,
delay: delay_or_id,
timeout : false
};
rd_counter++;
return this; // RETURN JQUERY OBJECT
}
})();