Show all items in AutocompleteTextView without writing text

Question

I have a AutocompleteTextView and it works fine. When I write a word it shows the relevant result but I want to show all items without writing any word in AutocompleteTextVi

Answer 1

Nothing Custom Required.

I tried All solutions but in some case that does not work. For Example one solution work for first time but when you remove text it will not appear. So I dug more and found following solution.

Suggestions are welcome.

XML:

Kotlin:

val adapter = ArrayAdapter(context, android.R.layout.select_dialog_item, listItems)
autoComplete.setAdapter(adapter)
//threshold specifies the minimum number of characters the user has to type in 
//the
//edit box before the drop down list is shown
autoComplete.threshold = 0

//we have to add check for 0 number of character in edit text. When that 
//happens, we will show pop up manually
autoComplete.addTextChangedListener(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) {
        //first check if length of input is 0
        if(s?.length ?: 0 == 0){
            //if you don't use handler with post delay, the API will hide pop 
            //up, even if you show it. There could be better ways to this, but 
            //I have implemented this and after 100 millis it gives an animated 
            //look
            Handler().postDelayed({
                //manually show drop down
                autoComplete.showDropDown()
            }, 100) // with 100 millis of delay
        }
    }
})
//when user focus out the view, drop down vanishes. When come back it will not 
//show, so to cover this scenario add following.
autoComplete.setOnFocusChangeListener { _, hasFocus ->
    //when gain focus manually show drop down
    if(hasFocus)
        autoComplete.showDropDown()
}