小弟刚刚入门，今天在学习关于textFiled控件的使用，VS2012开发平台，发现能输入，但按下backSpace键时不能撤销，希望能有大神解答
附上代码
TextFieldTTF *tf=TextFieldTTF::textFieldWithPlaceHolder("你好","宋体",20);
tf->setPosition(size.width/2,size.height/4);
auto listener=EventListenerTouchOneByOne::create();
listener->onTouchBegan==](Touch *t,Event *e){
if(tf->getBoundingBox().containsPoint(t->getLocation())){ //判断触摸点是否在方框之内
tf->attachWithIME();
}else
{
tf->detachWithIME();
}
return false;
};//创建一个单机监听器
Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(listener,tf);//为tf对象增加事件
addChild(tf);