模仿小红书，用kotlin写一个适用于安卓的EditView

好的，我明白了。关于您提出的问题，我可以为您提供以下代码：

class RedBookEditView @JvmOverloads constructor(
        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : EditText(context, attrs, defStyleAttr) {

    private var delegate: RedBookDelegate? = null
    private var hintTextView: TextView? = null

    init {
        initAttrs(context, attrs, defStyleAttr)
        initView()
    }

    private fun initAttrs(context: Context, attrs: AttributeSet?, defStyleAttr: Int) {
        val ta = context.obtainStyledAttributes(attrs, R.styleable.RedBookEditView, defStyleAttr, 0)
        val hintResId = ta.getResourceId(R.styleable.RedBookEditView_rbev_hint, 0)
        hintTextView = TextView(context)
        hintTextView!!.setTextColor(resources.getColor(R.color.hint_text_color))
        hintTextView!!.textSize = 14f
        hintTextView!!.text = resources.getText(hintResId)
        addView(hintTextView, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)
        ta.recycle()
    }

    private fun initView() {
        delegate = RedBookDelegate(this)
        hintTextView!!.setOnClickListener {
            setSelection(length())
            requestFocus()
        }
        setOnFocusChangeListener { _, hasFocus ->
            delegate!!.setFocus(hasFocus)
            if (hasFocus) {
                hintTextView!!.visibility = View.GONE
            } else {
                hintTextView!!.visibility = View.VISIBLE
            }
        }
        addTextChangedListener(object : TextWatcher {
            override fun afterTextChanged(s: Editable?) {
                delegate!!.handleTextChanged(s)
            }

            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
                delegate!!.handleTextChangedBefore(s, start, count, after)
            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
                delegate!!.handleTextChangedOn(s, start, before, count)
            }
        })
    }

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        val hintTextViewWidthMeasureSpec = MeasureSpec.makeMeasureSpec(measuredWidth - paddingLeft - paddingRight, MeasureSpec.EXACTLY)
        val hintTextViewHeightMeasureSpec = MeasureSpec.makeMeasureSpec(measuredHeight - paddingTop - paddingBottom, MeasureSpec.EXACTLY)
        hintTextView!!.measure(hintTextViewWidthMeasureSpec, hintTextViewHeightMeasureSpec)
    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        if (text.isNullOrEmpty()) {
            hintTextView!!.visibility = View.VISIBLE
        } else {
            hintTextView!!.visibility = View.GONE
        }
    }
}

这是一个 `EditText` 的子类，主要实现了类似小红书的 hint 文字效果，当输入框没有内容时，在输入框内自动显示灰色的提示文字。同时，为了加强体验，还重载了 `onFocusChanged` 和 `onDraw` 方法，当输入框获得/失去焦点时，隐藏/显示提示文字。

我希望这个代码能够对您有所帮助！