Preload基礎(chǔ)使用方法詳解

var queue = new createjs.LoadQueue(true);

var canvas = document.getElementById("myCanvas");
var stage = new createjs.Stage(canvas);
var manifest;
var preload;
var progressText = new createjs.Text("", "20px Arial", "#dd4814");
progressText.x = 125 - progressText.getMeasuredWidth() / 2;
progressText.y = 20;
stage.addChild(progressText);
stage.update();
//定義相關(guān)JSON格式文件列表
function setupManifest() {
  manifest = [{
    src: "http://cdn.gbtags.com/EaselJS/0.7.1/easeljs.min.js", 
    id: "easeljs"
  }, {
    src: "https://cache.yisu.com/upload/information/20200622/114/7302.jpg",
    id: "logo"
  }, {
    src: "http://www.gbtags.com/tutorials/html5-tutorial/html5-demos/assets/song.ogg",
    id: "audiofile"
  }
 
  ];
  for(var i=1;i<=10;i++)
    manifest.push({src:"http://www.gbtags.com/gb/laitu/200x200"})
}
//開始預(yù)加載
function startPreload() {
  preload = new createjs.LoadQueue(true);
  //注意加載音頻文件需要調(diào)用如下代碼行
  preload.installPlugin(createjs.Sound);     
  preload.on("fileload", handleFileLoad);
  preload.on("progress", handleFileProgress);
  preload.on("complete", loadComplete);
  preload.on("error", loadError);
  preload.loadManifest(manifest);
 
}
//處理單個(gè)文件加載
function handleFileLoad(event) {
  console.log("文件類型: " + event.item.type);
  if(event.item.id == "logo"){
    console.log("logo圖片已成功加載");
  }
}
 
//處理加載錯(cuò)誤：大家可以修改成錯(cuò)誤的文件地址，可在控制臺(tái)看到此方法調(diào)用
function loadError(evt) {
  console.log("加載出錯(cuò)！",evt.text);
}
 
//已加載完畢進(jìn)度 
function handleFileProgress(event) {
  progressText.text = "已加載 " + (preload.progress*100|0) + " %";
  stage.update();
}
//全度資源加載完畢
function loadComplete(event) {
  console.log("已加載完畢全部資源");
}
setupManifest();
startPreload();