java - 如何删除TextChangedListener？

Question

我想使用 EditText 在数据库中搜索，然后将项目添加到 RecylerView。现在我可以只搜索一个项目，项目显示，更改编辑文本后它消失，我希望它保留，我希望我搜索的每个项目都自动添加到 RecyclerView。所以我想我可以删除ChangeTextListener，然后再次添加它来搜索另一个项目，依此类推(？)

在MainActivity.kt中

fun Threads() {
        editText.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(
                s: CharSequence, start: Int,
                count: Int, after: Int
         ) {
            }

            override fun onTextChanged(
                s: CharSequence, start: Int,
                before: Int, count: Int
            ) {
                Thread {
//here we search for item
                    val itemsList = db?.costDAO()!!.getByName(s.toString())

                    runOnUiThread {
//here we pass item to Adapter constructor
                            recyclerView.adapter = MyAdapter(this@MainActivity, itemsList)
                            adapter.notifyDataSetChanged()

                    }
                }.start()
            }

            override fun afterTextChanged(s: Editable) { }

成本.DAO

@Dao
interface CostDAO {

    @Query("select * from cost where name like :name")
    fun getByName(name : String) : List<Cost>

Answer 1

罗伯特的回答不正确。这将导致崩溃

java.lang.NullPointerException:尝试在空对象引用上调用接口(interface)方法“void android.text.TextWatcher.beforeTextChanged(java.lang.CharSequence, int, int, int)”

您不能使用匿名类，因为您需要存储它才能删除。

val textWatcher = object :TextWatcher {
                    override fun afterTextChanged(s: Editable?) {}

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

                    override fun onTextChanged(
                        s: CharSequence?,
                        start: Int,
                        before: Int,
                        count: Int
                    ) {
                        //Do stuff
                    }

                }
binding.etEmail.addTextChangedWatcher(textWatcher)
// do what you need to do and later on
// ...
//
binding.etEmail.removeTextChangeWatcher(textWatcher)