当您单击另一个窗口并返回时，画布会自动运行。
我添加了关键侦听器，当您单击w a s d或up、left、right、时，它们会使船移动down。
一切正常，直到您单击向上和向右等两个按钮，然后单击另一个选项卡或窗口并返回。然后它会继续移动而不听你的输入。
我认为问题是，当您单击页面时，画布永远不会检查键是否被留下。但是当您单击屏幕时，如何使所有键都像未按下一样？当你离开屏幕时敌人也会消失这是按下按钮时发生的情况：
Player.prototype.checkKeys = function() //these functions are in the PLayer class
{
if(this.isUpKey == true)//if true
{
if(Player1.drawY >= 0)
{
this.drawY -= this.Speed;
}
}
if(this.isRightKey == true)
{
if(Player1.drawX <= (canvasWidthShips - this.playerWidth))
{
this.drawX += this.Speed;
}
}
if(this.isDownKey == true)
{
if(Player1.drawY <= (canvasHeightShips - this.playerHeight))
{
this.drawY += this.Speed;
}
}
if(this.isLeftKey == true)
{
if(Player1.drawX >= 0)
{
this.drawX -= this.Speed;
}
}
};
这些是我检查何时按下键的简单功能，我不认为错误在这里但不确定？
function checkKeyDown(e)
{
if (Paused == false)
{
var KeyID = e.KeyCode || e.which;
if (KeyID === 38 || KeyID === 87) //up and w keyboard buttons
{
Player1.isUpKey = true;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 39 || KeyID === 68) //right and d keyboard buttons
{
Player1.isRightKey = true;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 40 || KeyID === 83) //down and s keyboard buttons
{
Player1.isDownKey = true;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 37 || KeyID === 65) //left and a keyboard buttons
{
Player1.isLeftKey = true;
e.preventDefault(); //webpage dont scroll when playing
}
}
else if (Paused == true)
{
Player1.isUpKey = false;
Player1.isDownKey = false;
Player1.isRightKey = false;
Player1.isLeftKey = false;
}
}
function checkKeyUp(e)
{
if (Paused == false)
{
var KeyID = e.KeyCode || e.which;
if (KeyID === 38 || KeyID === 87) //up and w keyboard buttons
{
Player1.isUpKey = false;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 39 || KeyID === 68) //right and d keyboard buttons
{
Player1.isRightKey = false;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 40 || KeyID === 83) //down and s keyboard buttons
{
Player1.isDownKey = false;
e.preventDefault(); //webpage dont scroll when playing
}
if (KeyID === 37 || KeyID === 65) //left and a keyboard buttons
{
Player1.isLeftKey = false;
e.preventDefault(); //webpage dont scroll when playing
}
}
else if (Paused == true)
{
Player1.isUpKey = false;
Player1.isDownKey = false;
Player1.isRightKey = false;
Player1.isLeftKey = false;
}
}