Image refreshing with setInterval() - javascript

I have 4 divĀ“s each contains an image item and a select list of 4 div-id. I want to refresh the images simultaneously by changing the source of each image every 2 seconds.
I'm using setInterval() for each image and the problem is when I must stop all the timers at the same time.
Should I make a timer variable per div/img?
$(.div-id option:selected).each(function(){
var timer = setInterval(function(){
$(.div-id img).attr("src", "new-source-path");
},2000);
});
How can I stop all the active timers at once without stopping every timer Id?
Is there any solution with setTimeout() or any plugin to do that?

I'd opt for a single timer that loops through all images. Then when the timer isn't needed anymore I can just discard the single timer.
var timer = setInterval(swapImages, 2000);
function swapImages() {
$(.div-id option:selected).each(function(){
$(.div-id img).attr("src", "new-source-path");
});
}
// some time later
clearInterval(timer);
PS. I assume that your code is some pseudo code so I copied your namings

The end solution
function swapImages() {
$(".div-id-list option:selected").each(function () {
var url = "new-source-path";
$("#div-id img").attr("src", url);
});
}
function stopTimer() {
clearInterval(timer);
}
$(".div-id-list").on("change", function () {
stopTimer();
timer = setInterval(swapImages, 2000);
});
Thanks to donnywals !

Related

Redirect with inactivity

My objective is to keep a user in a view as long as he/she keeps clicking a button within a certain lapse.
I'm using Rails and was exploring a solution via an embedded JS in the pertinent view.
So far I'm able to set a time after which the user will be redirected to root path with the following script:
var delayedRedirect = function (){
window.location = "/";
}
var delay = 10000;
$(document).ready(function() {
setTimeout('delayedRedirect()', delay);
});
I've been trying to write a function that resets the value of 'delay'or that calls the setTimeoutFunction again.
$('#btn-persist').click(function() {
delay = 3000;
// or calling again setTimeout('delayedRedirect()', delay);
});
But I noticed that changing the variable won't affect the setTimeout function that has already been called.
I've also tried to use the clearTimeout function as below without success
var delayedRedirect = function (){
window.location = "/persists";
}
var delay = 3000;
var triggerRedirect = function() { setTimeout('delayedRedirect()', delay);
}
var stopRedirect = function (){
clearTimeout(triggerRedirect);
}
$(document).ready(function() {
triggerRedirect();
$('#btn-persist').click(function() {
stopRedirect();
});
});
I wonder why this may not be working and if there's any other way to stop the execution of the setTimeout function that has already been called so I can call it again to effectively reset the time to the original value of 'delay'.
At the same time, I don't want to stop any other JS functions that are running in parallel.
Do you see a better solution to achieve this?
The main problem why clearTimeout is not working. because you are clearing a anonymous function instead of a setTimeout variable
change this
var triggerRedirect = function() { setTimeout('delayedRedirect()', delay);
}
to this
var triggerRedirect = setTimeout('delayedRedirect()', delay);
Edit:
also change this (if you want to restart the inactive redirect trigger)
$('#btn-persist').click(function() {
stopRedirect();
});
to this
$('#btn-persist').click(function() {
stopRedirect();
triggerRedirect();
});

AngularJS: reset $timeout for each page switch

I'm working on my first AngularJS project and I'm working on a timeout that redirects the user to the startpage after a few minutes if they haven't clicked on anything. timeout is called on each page load to restart the timeout.
But the my problem is that restart() is called multiple times. One time for each page/view load. I use ngRoute.
For example if has clicked on three pages, timeout() has now been called three times and when the $timeout reaches the time, restart() is called three times.
myapp.controller(..., [...], function(...) {
function restart() {
$location.path("/slide/1");
}
function timeout() {
var timeoutHandle = $timeout(function() {
$timeout.cancel(timeoutHandle);
restart();
}, timeoutTime);
}
timeout();
}
Try to use this code:
var redirectTimeout;
var redirect = function() {
$location.path("/slide/1");
}
$timeout.cancel(redirectTimeout);
redirectTimeout = $timeout(function() {
var timeoutTime = 5000 // five seconds
redirectTimeout = $timeout(redirect, timeoutTime);
});
Here is the JSFiddle
Wouldn't it be better to put this kind of functionality inside a factory?

My Javascript timer counting down too fast or it doesn't start onLoad

I have that Javascript counter:
var x=100;
function timerCountdown()
{
document.getElementById('timer1').value=x;
x--;
t=setTimeout("timerCountdown()",1000);
if (x<-1)
{
document.getElementById('timer1').value='Done!';
clearTimeout(t);
}
}
function stopCounter(){
clearTimeout(t);
x=x+1;
}
Then I use:
<body onFocus='timerCountdown()' onBlur='stopCounter()'>
But the problem is, the countdown doesn't start when the page loads. It waits for me to click on another window and to reFocus on the window again.
So I tried this:
<body onLoad='timerCountdown()' onFocus='timerCountdown()' onBlur='stopCounter()'>
But this time, the countdown goes pretty fast. Probably because timerCOuntdown is called twice every second.
Alternatively, I could just use the onFocus and onBlur in the body tag, but I need a function to trigger the Focus upon body load. Is that possible?
Does anyone have a suggestion to solve this problem?
thanks a lot!
The simple answer is because setTimeout is invoked twice, running timerCountdown() once for two times separately, and continually setting two setTimeout IDs.
This would be what you want:
var x = 100;
var t = 0;
function timerCountdown()
{
if (t == 0) t = setInterval(timerCountdown, 1000);
document.getElementById('timer1').value=x;
x--;
if (x < 0)
{
document.getElementById('timer1').value='Done!';
clearTimeout(t);
ticker = 0;
}
}
function stopCounter()
{
clearTimeout(t);
t = 0;
x++;
}
setInterval is much more suited for countdown timers, and things you need to run continually since setTimeout only runs once and you need to keep on calling it.
Edit: This fixes the initial rapid triggering of the timer on Firefox.
Remove the handler from <body onload= and add this to the end of the script block above:
t = setInterval(timerCountdown, 1000);

Other way to "wait" during javascript animation

i'm looking for another way to execute this code :
$.each($("#gallery > img"), function(index,curImg) {
setTimeout(function() {
clearCanvas();
cvsCtx.drawImage(curImg,0,0);
} , index*animationMs);
});
This code draw an image from my gallery to my canvas every animationMs .
But i would like to make it possible to stop the animation, with a "Play/stop" button, I can't do it this way...
Any idea or workaround ?? thank you !!
I can't test it. But you can stop animation by using a variable to hold the setTimeout function as following:
var x; // public var
....
x = setTimeout(......);
// To stop it use:
clearTimeout(x);
Hope this works for you
I find that creating timeouts in a loop is usually too hard to manage - you don't want to have to cancel multiple timeouts. Better to have the function doing the work call itself (indirectly) by setting a timeout just before it completes, because then you can put in a simple if test to decide whether to set the next timeout and continue your animation.
Perhaps a little something like this:
<input id="playPause" type="button" value="Play">
<script>
function initAnimation(animationMs, autoRepeat, waitForPlayButton) {
var currentFrame = 0,
$imgList = $("#gallery > img"),
paused = waitForPlayButton;
function drawNext() {
clearCanvas();
cvsCtx.drawImage($imgList[currentFrame++],0,0);
if (currentFrame >= $imgList.length) {
currentFrame = 0;
if (!autoRepeat) {
paused = true;
$("playPause").prop("value", "Play");
}
}
if (!paused)
setTimeout(drawNext, animationMs);
}
$("playPause").prop("value", waitForPlayButton ? "Play" : "Pause")
.click(function() {
this.value = (paused = !paused) ? "Play" : "Pause";
if (!paused)
drawNext();
});
if (!waitForPlayButton)
drawNext();
}
initAnimation(100, true, false);
</script>
If autoRepeat param is false the animation will run once and stop, but can be restarted via the button, otherwise (obviously) it just keeps repeating.
If waitForPlayButton is false the animation will start immediately, otherwise (obviously) it will start when the button is pressed.
Pressing the button will pause at the current frame.
(Not tested since I don't have a bunch of images handy, but I'm sure you get the idea and can fix any problems yourself. Or let me know if you get errors...)
var images = $("#gallery > img").clone(), interval;
function startLoop() {
interval = setInterval(function(){
var image = images[0];
clearCanvas();
cvsCtx.drawImage(image,0,0);
images.append(image);
}, animationMs);
}
$(".stop").click(function() {clearInterval(interval);});
$(".start").click(startLoop);
setTimeout return a timeoutID which can be given to clearTimeout as a parameter to stop the timeout from happening.
You can read more about this at: https://developer.mozilla.org/en/DOM/window.setTimeout
Good luck
It's not really an animation... but still:
$("#gallery > img").each(function(index,curImg) {
$(this).delay(index*animationMs).queue(function(next) {
clearCanvas();
cvsCtx.drawImage(curImg,0,0);
if (next) next();
});
});
Using jQuery queues like I did allows you to do .stop(true), on $("#gallery > img") or a single image and stop their "animation".
First you could add images to a javascript array variable (eventually global) and then call a function cycle() on that array for all its length.
You should put your setTimeout() call inside that function, assigning it to a variable: var t=setTimeout("cycle()",animationMs); and execute clearTimeout(t); when you want to stop the animation.
Of course you could also save in a variable the frame where you were when stopping the animation and restart exactly from that frame when pressing "play" button.

Call a javascript function after 5 sec of last key press

I have a form with an <input type=text /> and I want to call a javascript function after 5 seconds of the last key press, and every time a new key is pressed, this timer should reset and only call the function after 5 seconds.
How can I do this?
I'm using jQuery.
thanks!
Something like this should get you started:
var timeout;
$('input[type=text]').keypress(function() {
if(timeout) {
clearTimeout(timeout);
timeout = null;
}
timeout = setTimeout(myFunction, 5000)
})
This answer is great, but remember that you need to enable this code after the documents loads and after the function loads to clear the timeout.
Here is the complete code:
var timeout;
$(document).ready(function(){
$('input[type=text]').keypress(function() {
if(timeout) {
clearTimeout(timeout);
timeout = null;
}
timeout = setTimeout(myFunction, 5000);
});
});
var myFunction = new function() {
alert('myFunction is running');
clearTimeout(timeout); // this way will not run infinitely
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
Although it doesn't use jQuery, you could also have a look at the debouncing function described here.
Steve

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