如何在 DialogFragment 中实现 TextWatcher

Question

在我的应用程序中，我在对话框片段内创建了一个可搜索列表。顶部是我的 editText，其中应用了 TextWatcher。

但是，当 TextWatcher 从 onCreateDialog 中连接到 EditText 时，我得到 "java.lang.IllegalStateException: search_box must not be null"。当它被放置在 onViewCreated 中时，onViewCreated 甚至都不会被调用。

有人可以解释一下我错过了什么吗？非常感谢

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    val layoutInflater = activity.layoutInflater
    val mainView = layoutInflater.inflate(R.layout.search_p, null)
    val builder = AlertDialog.Builder(activity)
    builder.setView(mainView)

    val layout = mainView.findViewById(R.id.results_layout) as LinearLayout
    var line = 0

    for(i in nameList){
        createButton(line,layout)
        line++
    }

    //Below line: java.lang.IllegalStateException: search_box must not be null
    search_box.afterTextChanged {
        val search = search_box.text.toString().toLowerCase()
        line = 0
        layout.removeAllViews()
        for(i in nameList){
            if(contains(search,nameList[line].toLowerCase())){
                createButton(line,layout)
            }
            line++
        }
    }

    return builder.create()
}

private fun EditText.afterTextChanged(afterTextChanged: (String)-> Unit) {
    this.addTextChangedListener(object: TextWatcher {
        override fun beforeTextChanged(p0:CharSequence?,p1:Int,p2:Int,p3:Int) { }
        override fun onTextChanged(p0:CharSequence?,p1:Int,p2:Int,p3:Int) {  }
        override fun afterTextChanged(editable: Editable?){
            afterTextChanged.invoke(editable.toString())
        }
    }) }

Answer 1

你的 Edittext 似乎是空的。

确保您的 Edittext 不为空

val search_box = mainView.findViewById(R.id.youredittext) as EditText


search_box.afterTextChanged {
   // do whatever
}

如何在 DialogFragment 中实现 TextWatcher

How to Implement a TextWatcher in a DialogFragment

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