Kotlin extensions

TypeExtensions.kt

fun Date.toCalendar(): Calendar = Calendar.getInstance().apply { this.time = this@toCalendar }

fun Calendar.addDayOfMonth(amount: Int): Calendar {
    this.add(Calendar.DAY_OF_MONTH, amount)
    return this
}

fun Calendar.formatTo(formatter: SimpleDateFormat): String {
    return formatter.format(this.timeInMillis)
}

val Calendar.year: Int get() = this.get(Calendar.YEAR)

var Calendar.month: Int
    get() = this.get(Calendar.MONTH)
    set(value) = this.set(Calendar.MONTH, value)

val Calendar.dayOfMonth: Int get() = this.get(Calendar.DAY_OF_MONTH)

inline fun <T> Iterable<T>.sumByFloat(selector: (T) -> Float): Float {
    var sum = 0f
    for (element in this) {
        sum += selector(element)
    }
    return sum
}

fun String.toIntOrZero(): Int = if (this.isEmpty()) 0 else this.toInt()

fun String.toFloatOrZero(): Float = if (this.isEmpty()) 0f else this.toFloat()

ViewExtension.kt

val TextView.textString: String get() = this.text.toString()

fun Button.dependsOnNotEmpty(vararg editTexts: EditText) {
    val textWatcher = object : SimpleTextWatcher() {
        override fun afterTextChanged(s: Editable?) {
            for (edit in editTexts) {
                if (edit.text.isEmpty()) {
                    this@dependsOnNotEmpty.isEnabled = false
                    return
                }
            }
            this@dependsOnNotEmpty.isEnabled = true
        }
    }
    editTexts.forEach { it.addTextChangedListener(textWatcher) }
}

fun Button.dependsOn(vararg editTexts: EditText, isEnabled: (() -> Boolean)){
    val textWatcher = object : SimpleTextWatcher() {
        override fun afterTextChanged(s: Editable?) {
            this@dependsOn.isEnabled = isEnabled()
        }
    }
    editTexts.forEach { it.addTextChangedListener(textWatcher) }
}