Android Studio返回页面时如何隐藏字符计数TextView控件

我给对应的EditText设置了焦点监听：获取焦点时显示字符计数TextView，失去焦点时隐藏该控件。但切换到其他Fragment再返回当前页面时，所有字符计数控件都会自动显示，点击单个控件后才恢复正常逻辑。我需要返回该Fragment时，字符计数TextView保持隐藏状态。

问题根源是Fragment切换回前台时，视图状态未被正确重置。我们需要主动同步EditText的焦点、文本状态与计数控件的可见性，具体处理如下：

1. 初始化默认隐藏：视图创建阶段直接将所有计数TextView设为隐藏，避免初始化时默认显示。
2. TextWatcher加焦点判断：仅当EditText处于获焦状态时，才根据文本内容更新计数控件可见性，防止无焦点时文本变化导致控件误显示。
3. 重写onResume方法：Fragment回到前台时，主动遍历所有EditText，根据当前状态重置计数控件的可见性。
4. 封装通用方法：减少重复代码，统一处理EditText与计数控件的状态同步逻辑。

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    
    // 初始化时默认隐藏所有计数控件
    itemView.cCount1.visibility = View.GONE
    itemView.cCount2.visibility = View.GONE
    itemView.cCount3.visibility = View.GONE
    itemView.cCount4.visibility = View.GONE
    itemView.cCount5.visibility = View.GONE

    /** 焦点状态监听 */
    itemView.date_time_add.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
        itemView.cCount1.visibility = if (hasFocus) View.VISIBLE else View.GONE
        // 获焦且文本非空时更新计数文本
        if (hasFocus && !itemView.date_time_add.text.isNullOrEmpty()) {
            itemView.cCount1.text = "${255 - itemView.date_time_add.text.length} 剩余字符"
        }
    }
    itemView.cable_run_add.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
        itemView.cCount2.visibility = if (hasFocus) View.VISIBLE else View.GONE
        if (hasFocus && !itemView.cable_run_add.text.isNullOrEmpty()) {
            itemView.cCount2.text = "${255 - itemView.cable_run_add.text.length} 剩余字符"
        }
    }
    itemView.entrance_add.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
        itemView.cCount3.visibility = if (hasFocus) View.VISIBLE else View.GONE
        if (hasFocus && !itemView.entrance_add.text.isNullOrEmpty()) {
            itemView.cCount3.text = "${255 - itemView.entrance_add.text.length} 剩余字符"
        }
    }
    itemView.door_lock_add.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
        itemView.cCount4.visibility = if (hasFocus) View.VISIBLE else View.GONE
        if (hasFocus && !itemView.door_lock_add.text.isNullOrEmpty()) {
            itemView.cCount4.text = "${1200 - itemView.door_lock_add.text.length} 剩余字符"
        }
    }
    itemView.handicap_operator_add.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
        itemView.cCount5.visibility = if (hasFocus) View.VISIBLE else View.GONE
        if (hasFocus && !itemView.handicap_operator_add.text.isNullOrEmpty()) {
            itemView.cCount5.text = "${1200 - itemView.handicap_operator_add.text.length} 剩余字符"
        }
    }

    /** 文本变化监听（增加焦点判断） */
    itemView.date_time_add.addTextChangedListener(object : TextWatcher {
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {
            if (itemView.date_time_add.hasFocus()) {
                itemView.cCount1.visibility = if (s.isNullOrEmpty()) View.GONE else View.VISIBLE
            }
        }

        override fun afterTextChanged(s: Editable?) {
            if (!s.isNullOrEmpty() && itemView.date_time_add.hasFocus()) {
                itemView.cCount1.text = "${255 - s.length} 剩余字符"
            }
        }
    })

    itemView.cable_run_add.addTextChangedListener(object : TextWatcher {
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {
            if (itemView.cable_run_add.hasFocus()) {
                itemView.cCount2.visibility = if (s.isNullOrEmpty()) View.GONE else View.VISIBLE
            }
        }

        override fun afterTextChanged(s: Editable?) {
            if (!s.isNullOrEmpty() && itemView.cable_run_add.hasFocus()) {
                itemView.cCount2.text = "${255 - s.length} 剩余字符"
            }
        }
    })

    itemView.entrance_add.addTextChangedListener(object : TextWatcher {
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {
            if (itemView.entrance_add.hasFocus()) {
                itemView.cCount3.visibility = if (s.isNullOrEmpty()) View.GONE else View.VISIBLE
            }
        }

        override fun afterTextChanged(s: Editable?) {
            if (!s.isNullOrEmpty() && itemView.entrance_add.hasFocus()) {
                itemView.cCount3.text = "${255 - s.length} 剩余字符"
            }
        }
    })

    itemView.door_lock_add.addTextChangedListener(object : TextWatcher {
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {
            if (itemView.door_lock_add.hasFocus()) {
                itemView.cCount4.visibility = if (s.isNullOrEmpty()) View.GONE else View.VISIBLE
            }
        }

        override fun afterTextChanged(s: Editable?) {
            if (!s.isNullOrEmpty() && itemView.door_lock_add.hasFocus()) {
                itemView.cCount4.text = "${1200 - s.length} 剩余字符"
            }
        }
    })

    itemView.handicap_operator_add.addTextChangedListener(object : TextWatcher {
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, count: Int, end: Int) {
            if (itemView.handicap_operator_add.hasFocus()) {
                itemView.cCount5.visibility = if (s.isNullOrEmpty()) View.GONE else View.VISIBLE
            }
        }

        override fun afterTextChanged(s: Editable?) {
            if (!s.isNullOrEmpty() && itemView.handicap_operator_add.hasFocus()) {
                itemView.cCount5.text = "${1200 - s.length} 剩余字符"
            }
        }
    })
}

// Fragment回到前台时重置控件状态
override fun onResume() {
    super.onResume()
    updateCountView(itemView.date_time_add, itemView.cCount1, 255)
    updateCountView(itemView.cable_run_add, itemView.cCount2, 255)
    updateCountView(itemView.entrance_add, itemView.cCount3, 255)
    updateCountView(itemView.door_lock_add, itemView.cCount4, 1200)
    updateCountView(itemView.handicap_operator_add, itemView.cCount5, 1200)
}

// 封装通用方法，同步EditText和计数控件状态
private fun updateCountView(editText: EditText, countView: TextView, maxLength: Int) {
    countView.visibility = if (editText.hasFocus() && !editText.text.isNullOrEmpty()) {
        countView.text = "${maxLength - editText.text.length} 剩余字符"
        View.VISIBLE
    } else {
        View.GONE
    }
}

内容的提问来源于stack exchange，提问作者OEThe11