按照道理不是應(yīng)該是fruit里面的fruitObj的num嗎按照老師的代碼對(duì)照了好幾遍，還是不行。名字也沒打錯(cuò)以下是代碼var?fruitObj?=function(){ ??????this.alive?=[]; ??????this.x=[]; ??????this.y=[]; ??????this.l=[]; ??????this.spd=[]; ??????this.orange=?new?Image(); ??????this.blue=?new?Image(); } fruitObj.prototype.num?=30; fruitObj.prototype.init?=function(){ ???????for?(??var?i=0?;i<this.num;i++) ???????{ ????????????this.alive[i]=false; ????????????this.x[i]=0; ????????????this.y[i]=0; ????????????this.spd[i]=?Math.random()*0.01+0.005;????? ???????????? ???????} ????????this.orange.src="./src/fruit.png"; ????????this.blue.src="./src/blue.png"; ???????? } fruitObj.prototype.draw=?function(){ ??????? ?????????for(?var?i=0;i<?this.num;i++){ ?????????????? ?????????????????//draw ?????????????????//find?an?ane,grow,fly?up ?????????????if?(?this.alive[i]){ ???????????????if(this.l[i]<=14){ ??????????????? ??this.l[i]+=this.spd[i]?*deltaTime; ???????????????} ???????????????else{ ???????????????????????this.y[i]-=?this.spd[i]*5?*deltaTime; ???????????????} ?????????????????ctx2.drawImage(this.orange,this.x[i]-this.l[i]*0.5,this.y[i]-this.l[i]*0.5,this.l[i],this.l[i]); ???????????????if(this.y[i]<0-this.orange.width){ ???????????????????this.alive[i]=false; ???????????????}} ????????????? ??????????????? ?????????} } fruitObj.prototype.born?=function(i){ ???????var?aneID=?Math.floor(Math.random()*ane.num); ???????this.x[i]?=ane.x[aneID]; ???????this.y[i]?=canHeight-ane.len[aneID]; ???????this.l[i]=0; ???????this.alive[i]=true; } function?fruitMonitor(){ ??????var?num=0; ????for(var?i=?0;i<fruit.num;i++) ????????{ ???????? ?if(?fruit.alive[i]??)?num++ ????????} ??? ??????if(num<15){ ?????????????sendFruit(); ?????? ?????return; ??????} ????????console.log("ni"); } function?sendFruit(){ ???????????for(var?i=0;i?<fruit.num;i++){ ?????????????????if?(!fruit.alive[i])?{ ????????????????? ?fruit.born(i); ????????????????? ?return; ?????????????????} ???????????} ??? }