[spike] Create Kotlin extensions for some interfaces in order to simplify usage

[axti]

Idea is to create extension functions to simplify usage of callback interface for kotlin developers. Here is an example: Instead of full implementation of interface:

gesturesPlugin.addOnMoveListener(object: OnMoveListener{
  override fun onMoveBegin(detector: MoveGestureDetector) {
    TODO("Not yet implemented")
  }

  override fun onMove(detector: MoveGestureDetector): Boolean {
    TODO("Not yet implemented")
  }

  override fun onMoveEnd(detector: MoveGestureDetector) {
    TODO("Not yet implemented")
  }

})

We will be able to short it to:

gesturesPlugin.doOnMoveBegin { 
  do something  
}

[VincentJoshuaET]

This is how Google does it:

public inline fun TextView.doBeforeTextChanged(
    crossinline action: (
        text: CharSequence?,
        start: Int,
        count: Int,
        after: Int
    ) -> Unit
): TextWatcher = addTextChangedListener(beforeTextChanged = action)

/**
 * Add an action which will be invoked when the text is changing.
 *
 * @return the [TextWatcher] added to the TextView
 */
public inline fun TextView.doOnTextChanged(
    crossinline action: (
        text: CharSequence?,
        start: Int,
        before: Int,
        count: Int
    ) -> Unit
): TextWatcher = addTextChangedListener(onTextChanged = action)

/**
 * Add an action which will be invoked after the text changed.
 *
 * @return the [TextWatcher] added to the TextView
 */
public inline fun TextView.doAfterTextChanged(
    crossinline action: (text: Editable?) -> Unit
): TextWatcher = addTextChangedListener(afterTextChanged = action)

/**
 * Add a text changed listener to this TextView using the provided actions
 *
 * @return the [TextWatcher] added to the TextView
 */
public inline fun TextView.addTextChangedListener(
    crossinline beforeTextChanged: (
        text: CharSequence?,
        start: Int,
        count: Int,
        after: Int
    ) -> Unit = { _, _, _, _ -> },
    crossinline onTextChanged: (
        text: CharSequence?,
        start: Int,
        before: Int,
        count: Int
    ) -> Unit = { _, _, _, _ -> },
    crossinline afterTextChanged: (text: Editable?) -> Unit = {}
): TextWatcher {
    val textWatcher = object : TextWatcher {
        override fun afterTextChanged(s: Editable?) {
            afterTextChanged.invoke(s)
        }

        override fun beforeTextChanged(text: CharSequence?, start: Int, count: Int, after: Int) {
            beforeTextChanged.invoke(text, start, count, after)
        }

        override fun onTextChanged(text: CharSequence?, start: Int, before: Int, count: Int) {
            onTextChanged.invoke(text, start, before, count)
        }
    }
    addTextChangedListener(textWatcher)

    return textWatcher
}

[tobrun]

Todo: create a list of APIs that we want to improve.