尝试每秒循环执行 [英] Trying to execute while loop every second
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问题描述
我需要这些while循环来执行每秒而不是瞬时执行。每当我加载机器人操作系统并使deltaX / Y大于20时，它就会跳到1000000.我希望它从1到1000000以每秒1步的速度运行。有人可以帮我这个。谢谢
< pre lang = 使用Javascript>
var xmax = 1000000 ;
var ymax = 1000000 ;
var negxmax = -1000000;
var negymax = -1000000;
var x = 1 ;
var y = 1 ;
while （joystick.deltaX（）> 20 && x< xmax）{
x = x + 1 ;
}
while （joystick.deltaX（）< - 20 & & x> negxmax）{
x = x - 1
}
while （joystick.deltaY（）> 20 && y< ymax）{
y = y + 1 ;
}
while （joystick.deltaY（）< -20&& y> negymax）{
y = y - 1 ;
}
解决方案
首先，你没有任何与时间有关的东西。你不能执行一个任意的循环，并保证它需要1秒才能完成循环。
所以，问题不在于如何使循环工作，它实际上是如何在javascript中每秒执行一次代码的。为了这个目的，使用setInterval。
谷歌的 javascript执行代码每x秒 [ ^ ]。
使用 Window setInterval（）方法 [< a href =http://www.w3schools.com/jsref/met_win_setinterval.asptarget =_ blanktitle =New Window> ^ ]。
调整以下内容示例代码：
< ！DOCTYPE html >
< html >
< 正文 >
< script >
var xmax = 5;
var x = 0;
var myTimer = setInterval（myFunction，1000）; // start timer
function myFunction（）{
if（x < xmax ）{
document.write（++ x + '< br > '）;
} else {
clearInterval（myTimer）; //停止计时器
}
}
< / script >
< / body >
< / html >
除了解决方案1.
很多时候，更新的方法更好，特别是在动画/游戏中：window.requestAnimationFrame。请参阅： http://paulirish.com/2011/requestanimationframe-for-smart-animating [< a href =http://paulirish.com/2011/requestanimationframe-for-smart-animatingtarget =_ blanktitle =New Window> ^ ]。
请查看我的游戏实现，您可以在其中找到该技术的一些有趣细节：画布上的俄罗斯方块 [ ^ ]。
另请注意使用setTimeout作为后备。这是为了以防万一。无论如何，当今非废话浏览器的所有JavaScript引擎都将实现requestAnimationFrame。
- SA
I need these while loops to execute every second instead of it being instantaneous. Whenever I load up robot operating system and make deltaX/Y greater than 20 it will just jump to a 1000000. I want it to go from 1 to 1000000 going in steps of 1 every second. Can someone please help me with this. Thanks
<pre lang="Javascript">
var xmax = 1000000;
var ymax = 1000000;
var negxmax = -1000000;
var negymax = -1000000;
var x = 1;
var y = 1;
while (joystick.deltaX() > 20 && x < xmax ){
x = x + 1;
}
while(joystick.deltaX() < - 20 && x > negxmax){
x = x - 1
}
while (joystick.deltaY() > 20 && y < ymax){
y = y + 1;
}
while (joystick.deltaY() < -20 && y > negymax){
y = y - 1;
} 解决方案
First, you have nothing in there that is time dependent. You cannot execute an arbitrary loop and guarantee that it's going to take 1 second to go through the loop.
So, the question is NOT how to make there loops work, it's really how do I execute code once a second in javascript. For that look into usingsetInterval.
Google for "javascript execute code every x seconds[^]".
Use Window setInterval() Method[^].
Adapt the following sample code:
<!DOCTYPE html> <html> <body> <script> var xmax = 5; var x = 0; var myTimer = setInterval(myFunction, 1000); // start timer function myFunction() { if (x < xmax ){ document.write(++x + '<br>') ; } else { clearInterval(myTimer); // stop timer } } </script> </body> </html>
In addition to the Solution 1.
Very often, newer approach is better, especially in animation/gaming:window.requestAnimationFrame. Please see: http://paulirish.com/2011/requestanimationframe-for-smart-animating[^].
Please look at my game implementation where you can find number of interesting detail of the technique: Tetris on Canvas[^].
Also note the use ofsetTimeoutas a fallback. This is done just in case. Anyway, all JavaScript engines of present-day non-nonsense browsers will implementrequestAnimationFrame.
—SA
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