Keyboard.kt

import android.content.Context
import android.view.View
import android.view.inputmethod.InputMethodManager
import android.widget.EditText

private fun View.getMethodManager() : InputMethodManager {
    return context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
}

fun View.showKeyboard(){
    getMethodManager().toggleSoftInputFromWindow(windowToken, InputMethodManager.SHOW_FORCED, 0)
}

fun View.hideKeyboard(){
    getMethodManager().hideSoftInputFromWindow(windowToken, 0)
}

// Only uses this when you change softInput in manifest
fun EditText.attachKeyboard(container: View) {
    setOnFocusChangeListener { _ , hasFocus ->
        if(hasFocus){
            container.showKeyboard()
        }else{
            container.hideKeyboard()
        }
    }
}

KeyboardUpdate.kt

import android.content.Context
import android.view.View
import android.view.ViewTreeObserver
import android.view.inputmethod.InputMethodManager
import android.widget.EditText
import androidx.annotation.IdRes
import com.thegar.viewhelper.R


/***
 *  Show keyboard on [EditText]
 *
 *  Better Implementation of showing keyboard
 *   - Keyboard will be automatically dismissed when navigating to other application
 *   - it did not need hideKeyboard method
 *
 *  [link](https://developer.squareup.com/blog/showing-the-android-keyboard-reliably/)
 */

fun EditText.showKeyboard() {
    fun EditText.showTheKeyboardNow() {
        if (isFocused) {
            post {
                // We still post the call, just in case we are being notified of the windows focus
                // but InputMethodManager didn't get properly setup yet.
                val keyboardBelow = getTag(R.id.ShowKeyboardBelow) as? View ?: this
                getMethodManager().showSoftInput(keyboardBelow, InputMethodManager.SHOW_IMPLICIT)
            }
        }
    }

    if (hasWindowFocus()) {
        showTheKeyboardNow()
    } else {
        // Wait until the window gets focus.
        runOnWindowFocus { showTheKeyboardNow() }
    }
}

/**
 *  This is placed inside of any Focusable Widget
 */

internal fun View.hideKeyboard(){
    getMethodManager().hideSoftInputFromWindow(windowToken, 0)
}

internal fun View.runOnWindowFocus(block : () -> Unit){
    viewTreeObserver.addOnWindowFocusChangeListener(
        object : ViewTreeObserver.OnWindowFocusChangeListener {
            override fun onWindowFocusChanged(hasFocus: Boolean) {
                // This notification will arrive just before the InputMethodManager gets set up.
                if (hasFocus) {
                    block.invoke()
                    // It’s very important to remove this listener once we are done.
                    viewTreeObserver.removeOnWindowFocusChangeListener(this)
                }
            }
        }
    )
}


internal fun View.getMethodManager() : InputMethodManager {
    return context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
}


/***
 *  Attach A View to EditText,
 *  You should reattach keyboard whenever [EditText] is detached from window
 *
 *  @param keyboardBelowView : Keyboard will be shown below this view
 */
fun EditText.attachKeyboard(keyboardBelowView: View) {
    setTag(R.id.ShowKeyboardBelow, keyboardBelowView)
    setOnFocusChangeListener { _ , hasFocus ->
        if(hasFocus){
            showKeyboard()
        }
    }

    // fix possible memory leak
    addOnAttachStateChangeListener(PreventLeakingTag(R.id.ShowKeyboardBelow))
}

fun EditText.attachKeyboard(){
    setOnFocusChangeListener { _ , hasFocus ->
        if(hasFocus){
            showKeyboard()
        }
    }
}

internal class PreventLeakingTag(
    @IdRes private val tagId : Int
) : View.OnAttachStateChangeListener {

    override fun onViewAttachedToWindow(v: View?) { }

    override fun onViewDetachedFromWindow(v: View?) {
        v?.setTag(tagId, null)
        v?.removeOnAttachStateChangeListener(this)
    }

}