jquery / javascript - storing reference to array - not array values
I'm trying to combine a few similar functions into a single functions, which need to make calls to different arrays / variables, but I'm not quite getting it right. Here's my code:
var initialPreloadArray = ['scenes/icons_orange.png','scenes/icons_blue.png','scenes/icons_green.png','site/pedestal_h.png']; //These must be loaded before we advance from the intro screen
var initialPreloadCounter = 0;
var secondaryPreloadArray = ['site/restart-black.png','site/back_black.png','interludes/city.png','interludes/town.png','interludes/country.png']; //These must be loaded before we can advance from the initial decision scene
var secondaryPreloadCounter = 0;
var vehiclesPreloadArray = ['vehicles/vehicles.png','site/close.png']; //These must be loaded before we can display the vehicles
var vehiclesPreloadCounter = 0;
var arrName; //Store the variable name of the array for the stage of preloading we're in
var arrCounter; //Stores the variable name of the counter for the stage of preloading we're in
function setPreloadStage(preloadStage){
if (preloadStage == initial){
arrName = initialPreloadArray;
arrCounter = initialPreloadCounter;
} else if (preloadStage == 'secondary'){
arrName = secondaryPreloadArray;
arrCounter = secondaryPreloadCounter;
} else if (preloadStage == 'vehicles'){
arrName = vehiclesPreloadArray;
arrCounter = vehiclesPreloadCounter;
}
preloadImages(preloadStage);
}
//Recurse through scene xml and populate scene array
function preloadImages(preloadStage) {
console.log(arrName[arrCounter]);
var img = new Image();
img.src = 'images/' + arrName[arrCounter];
if(!img.complete){
jQuery(img).bind('error load onreadystatechange', imageComplete(preloadStage));
} else {
imageComplete(preloadStag开发者_如何转开发e);
}
//$j.preloadCssImages({statusTextEl: '#textStatus', statusBarEl: '#status'});
}
function imageComplete(preloadStage){
arrCounter++;
var preloadLength = arrName.length-1;
if (arrName && preloadLength && arrName[arrCounter]) {
if (preloadLength == arrCounter){
if (preloadStage == 'initial'){
initialImagesLoaded();
} else if (preloadStage == 'secondary'){
secondaryImagesLoaded();
} else if (preloadStage == 'vehicles'){
vehiclesLoaded();
}
}
preloadImages(preloadStage);
}
}
Anybody have an idea what I'm doing wrong?
Actually, here’s an even more obvious problem:
jQuery(img).bind('error load onreadystatechange', imageComplete(preloadStage));
You would have to do this:
jQuery(img).bind('error load onreadystatechange', function () {
imageComplete(preloadStage)
});
I suggest that you should use an array to manage state.
define an array holding your stages, like this:
var stages = [
{
label : 'initial',
imgs : [ 'img/whoobee.png', ...more here...],
doneSoFar: 0,
allDone: function(){}
},
{ label : 'secondary', imgs : .....},
{ label : 'whatever', imgs : ....}
];
NB: You will need to set the "allDone" fn for each stage appropriately.
Then a fn that kicks off one stage:
function kickoffPreloadOneStage(stage) {
console.log ("preloading stage " + stage.label);
preloadNextImage(stage);
}
function preloadNextImage(stage) {
var img = new Image();
img.src = 'images/' + stage.imgs[stage.doneSoFar];
if(!img.complete){
jQuery(img).bind('error load onreadystatechange', function() {
imageComplete(preloadStage);
});
}
else {
imageComplete(preloadStage);
}
}
function imageComplete(stage){
stage.doneSoFar++;
var preloadLength = stage.imgs.length-1;
if (stage.doneSoFar == preloadLength) {
stage.allDone(); // call the allDone function. may want to pass stage back
}
else {
preloadNextImage(stage);
}
}
To do all stages, use code like this:
var i;
for(i=0; i < stages.length; i++) {
kickoffPreloadOneStage(stages[i]);
}
You can also go OO, defining those functions as members of a Stage() class, but ....what I suggested is a reasonable simplification without getting too complicated.
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