Add view extension functions (#2, #3)

* Visibility
* Keyobard
* Dimension

Author: enginebai

base/src/main/java/com/enginebai/base/extensions/ViewExt.kt

@@ -0,0 +1,95 @@
+package com.enginebai.base.extensions
+
+import android.content.Context
+import android.view.View
+import android.view.inputmethod.InputMethodManager
+
+//
+// visibility
+//
+fun View.setVisible(visible: Boolean) {
+	visibility = if (visible) View.VISIBLE else View.INVISIBLE
+}
+
+fun View.setExistence(exist: Boolean) {
+	visibility = if (exist) View.VISIBLE else View.GONE
+}
+
+inline fun View.showIf(predicate: () -> Boolean): View {
+	if (visibility != View.VISIBLE && predicate()) {
+		visibility = View.VISIBLE
+	}
+	return this
+}
+
+inline fun View.hideIf(predicate: () -> Boolean): View {
+	if (visibility != View.INVISIBLE && predicate()) {
+		visibility = View.VISIBLE
+	}
+	return this
+}
+
+inline fun View.goneIf(predicate: () -> Boolean): View {
+	if (visibility != View.GONE && predicate()) {
+		visibility = View.GONE
+	}
+	return this
+}
+
+fun View.gone() {
+	setExistence(false)
+}
+
+fun View.invisible() {
+	setVisible(false)
+}
+
+fun View.visible() {
+	visibility = View.VISIBLE
+}
+
+fun View.toggleVisible() {
+	visibility = if (visibility == View.VISIBLE) View.INVISIBLE else View.VISIBLE
+}
+
+fun View.toggleExistence() {
+	visibility = if (visibility == View.VISIBLE) View.GONE else View.VISIBLE
+}
+
+val View.isGone: Boolean get() = (visibility == View.GONE)
+val View.isInvisible: Boolean get() = (visibility == View.INVISIBLE)
+val View.isVisible: Boolean get() = (visibility == View.VISIBLE)
+
+//
+// keyboard
+//
+fun View.showKeyboard() {
+	val inputMethodManager =
+		context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
+	inputMethodManager.showSoftInput(this, InputMethodManager.SHOW_FORCED)
+}
+
+fun View.hideKeyboard() {
+	val inputMethodManager =
+		context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
+	inputMethodManager.hideSoftInputFromWindow(this.windowToken, 0)
+}
+
+//
+// dimension conversion
+//
+fun View.px2dp(px: Float): Int {
+	return (px / resources.displayMetrics.density + 0.5f).toInt()
+}
+
+fun View.dp2px(dp: Float): Int {
+	return (dp * resources.displayMetrics.density + 0.5f).toInt()
+}
+
+fun View.px2sp(px: Float): Int {
+	return (px / resources.displayMetrics.scaledDensity + 0.5f).toInt()
+}
+
+fun View.sp2px(sp: Float): Int {
+	return (sp * resources.displayMetrics.scaledDensity + 0.5f).toInt()
+}