为什么两个潜水器都不旋转

Question

我已经创建了Square作为一个对象，并给它提供了大小和旋转的原型，当我创建新的square1和square2并对它们调用rotate时，只有最后创建的div旋转是一个正方形，两者都需要旋转，"我认为这可能与className Square有关，但需要帮助修复它。两个Square都需要旋转。

谢谢

// global variables //
var angle = 0; //initialize angle
// Square Object //
var Square = function() {
    square = document.createElement('div');
    square.className = 'square';
    document.body.appendChild(square); //div created div name class square
}
// prototype size of Square
Square.prototype.size = function(width,height,margin) {
    square.style.width = width + 'px';
    square.style.height = height + 'px';
    square.style.margin = margin + 'px';
} 

//prototype rotate of Square 
Square.prototype.rotate = function rotA() {
    angle = (angle + 1)%360;
    square.style.transform = "rotate(" + angle + "deg)"
    window.requestAnimationFrame(rotA);
}

// create new square -------------
var square1 = new Square();
square1.size(250,250,250);
var square2 = new Square();
square2.size(500,500,125)
square1.rotate();
square2.rotate();

请参阅此处的fiddle：https://jsfiddle.net/gustav1105/c41fLbh0/

Answer 1

您需要在函数中使用this关键字。并且从window.requestAnimationFrame 调用时需要bind rotate函数

// Square Object //
var Square = function() {
    this.angle = 0;
	this.square = document.createElement('div');
	this.square.className = 'square';
	document.body.appendChild(this.square); //div created div name class square
}
// prototype size of Square
Square.prototype.size = function(width,height,margin) {
	this.square.style.width = width + 'px';
	this.square.style.height = height + 'px';
	this.square.style.margin = margin + 'px';
} 
//prototype rotate of Square 
Square.prototype.rotate = function() {
	this.angle = (this.angle + 1)%360;
	this.square.style.transform = "rotate(" + this.angle + "deg)"
	window.requestAnimationFrame(this.rotate.bind(this));
}
// create new square -------------
var square1 = new Square();
square1.size(250,250,250);
var square2 = new Square();
square2.size(500,500,125);
square1.rotate();
square2.rotate();

.square {
  position: absolute;
  left:0;
  top:0;
  border: 1px solid black;
}

Answer 2

检查一下这个fiddle，它不像你希望的那样面向对象，但如果你没有找到任何其他解决方案，你可以使用它

// global variables //
var angle = 0; //initialize angle
// Square Object //
var Square = function() {
    var square = document.createElement('div');
    square.className = 'square';
    square.style.backgroundColor = "#000";
    document.body.appendChild(square); //div created div name class square
    return square;
}
// prototype size of Square
Square.size = function(square, width,height,margin) {
    square.style.width = width + 'px';
    square.style.height = height + 'px';
    square.style.margin = margin + 'px';
} 

//prototype rotate of Square 
Square.rotate = function rotA(square) {
    angle = (angle + 1)%360;
    square.style.transform = "rotate(" + angle + "deg)"
    window.requestAnimationFrame(function(){ rotA(square) });
}

// create new square -------------
var square1 = new Square();
console.log(square1);
Square.size(square1,25,25,25);
var square2 = new Square();
Square.size(square2,25,25,25)
Square.rotate(square1);
Square.rotate(square2);

Answer 3

正如@gurvinder372所建议的，正方形并不是为每个square对象本地定义的，代码只是"忘记"了第一个实例。

请使用this关键字来引用原型扩展内部的实例变量。

这是一个JSFiddle