//懒加载文本输入框

    private lazy var textView: UITextView = {

        let textView = UITextView()

        textView.font = UIFont.systemFontOfSize()

        textView.textColor = UIColor.darkGrayColor()

 //处理键盘，设置键盘的消失模式

        textView.keyboardDismissMode = UIScrollViewKeyboardDismissMode.OnDrag

        //设置弹簧效果

        textView.alwaysBounceVertical = true

return textView

     }()

    //懒加载占位文本

    private lazy var placeHoderLabel: UILabel = UILabel(title: "分享新鲜事...", size: , color: UIColor.lightGrayColor())

//设置输入文本框

    private func setTextView() {

        //添加子控件

        view.addSubview(textView)

        textView.backgroundColor = UIColor.randomColor()


        //设置约束

        textView.snp_makeConstraints { (make) -> Void in

            make.top.left.right.equalTo(self.view)

            make.height.equalTo(view.bounds.height / )

        }

        //添加占位文本

        textView.addSubview(placeHoderLabel)

        //约束

        placeHoderLabel.snp_makeConstraints { (make) -> Void in

            make.top.equalTo(textView.snp_top).offset()

            make.left.equalTo(textView.snp_left).offset()

        }

    }