CODEWITHSUNDEEP
javaandroidtextwatcher
Ciara
Ciara

Reputation: 25

How to remove TextChangedListener?

I want to search in database using EditText, and then add items to RecylerView. Now i can just search one item, item displays, and after changing edit text it disappears, i want it to stay, i want every item I've searched for to automatically be added to RecyclerView. So I thought I can remove ChangeTextListener, and then add it again to search for another item, and so on(?)

In MainActivity.kt

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) { }

Cost.DAO

@Dao
interface CostDAO {

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

Upvotes: 2

Views: 3219

Answers (3)

Grzesiek Eman
Grzesiek Eman

Reputation: 86

The only way to remove the textWatcher from editText, is to have the exact object that you assigned stored somewhere, in a field for example or in a list.

then you can

binding.editText.removeTextChangeWatcher(textWatcher)

or, if you use multiple textWatchers, for example for recyclerView items,

textWatchers.forEach { vh.binding.editText.remoxeTextChangerWatcher(it) }

The only option to remove a textWatcher is to have it's refference stored, otherwise to pass it to the remove method.

Upvotes: 0

Hasansidd
Hasansidd

Reputation: 71

Robert's answer is incorrect. This will lead to a crash

java.lang.NullPointerException: Attempt to invoke interface method 'void android.text.TextWatcher.beforeTextChanged(java.lang.CharSequence, int, int, int)' on a null object reference

You can't use an anonymous class because you need to store it to remove.

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)

Upvotes: 6

Robert M.
Robert M.

Reputation: 94

To remove a listener you have to set it to null; I know you are using Kotlin but in Java would be something like this:

editText.addTextChangedListener(null);

Hope it helps!

Upvotes: -1

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