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我當時在玩JS遊戲。並擊中一個磚牆,無法從主html文件中的事件更改變量。就是說關閉SetX。爲什麼它不會改變?不能從外部事件中更改對象變量
var game = new Game();
window.addEventListener("keyup", game.input);
game.start('myCanvas');
遊戲對象看起來像這樣。
function Game() {
this.offSetX = 0;
this.init = function (id) {
this.canvas = document.getElementById(id);
this.context = this.canvas.getContext('2d');
this.blocks = [];
this.blocks.push(new block());
};
this.logic = function() {
for (var i in this.blocks) {
this.blocks[i].update(this.offSetX);
}
};
this.draw = function() {
for (var i in this.blocks) {
this.blocks[i].draw(this.context);
}
};
this.main = function() {
this.logic();
this.draw();
console.log(this.offSetX);
};
this.input = function (key) {
if (key.keyCode == 37) {
this.offSetX--;
console.log(this.offSetX);
}
if (key.keyCode == 39) {
this.offSetX++;
console.log(this.offSetX);
}
};
this.start = function (id) {
var _this = this;
this.init(id);
this.interval = setInterval(function() {
_this.canvas.width = _this.canvas.width;
_this.main();
}, 30);
}
};
嘗試添加'console.log(this)'作爲this.input方法的第一行。然後在你編寫'window.addEventListener(「keyup」,game.input)''時檢查'console',然後用我的答案替換該代碼並再次檢查。 – Engineer 2012-04-15 13:32:59