Add OnBalloonInitializedListener for listening initialized balloon co…

…ntent

balloon/src/main/java/com/skydoves/balloon/Balloon.kt

@@ -90,6 +90,7 @@ class Balloon(
   private var destroyed: Boolean = false
   var onBalloonClickListener: OnBalloonClickListener? = null
   var onBalloonDismissListener: OnBalloonDismissListener? = null
+  var onBalloonInitializedListener: OnBalloonInitializedListener? = null
   var onBalloonOutsideTouchListener: OnBalloonOutsideTouchListener? = null
   private var supportRtlLayoutFactor: Int = LTR.unaryMinus(builder.isRtlSupport)
   private val balloonPersistence = BalloonPersistence.getInstance(context)
@@ -151,6 +152,7 @@ class Balloon(
       }
       binding.root.post {
         binding.balloonArrow.visible(builder.arrowVisible)
+        onBalloonInitializedListener?.onBalloonInitialized(getContentView())
         when (builder.arrowOrientation) {
           ArrowOrientation.BOTTOM, ArrowOrientation.TOP -> {
             x = getArrowConstraintPositionX(anchor)
@@ -266,6 +268,7 @@ class Balloon(
   private fun initializeBalloonListeners() {
     this.onBalloonClickListener = builder.onBalloonClickListener
     this.onBalloonDismissListener = builder.onBalloonDismissListener
+    this.onBalloonInitializedListener = builder.onBalloonInitializedListener
     this.onBalloonOutsideTouchListener = builder.onBalloonOutsideTouchListener
     this.binding.root.setOnClickListener {
       this.onBalloonClickListener?.onBalloonClick(it)
@@ -867,6 +870,9 @@ class Balloon(
     @JvmField
     var onBalloonDismissListener: OnBalloonDismissListener? = null
 
+    @JvmField
+    var onBalloonInitializedListener: OnBalloonInitializedListener? = null
+
     @JvmField
     var onBalloonOutsideTouchListener: OnBalloonOutsideTouchListener? = null
 
@@ -1216,6 +1222,11 @@ class Balloon(
       this.onBalloonDismissListener = value
     }
 
+    /** sets a [OnBalloonInitializedListener] to the popup. */
+    fun setOnBalloonInitializedListener(value: OnBalloonInitializedListener): Builder = apply {
+      this.onBalloonInitializedListener = value
+    }
+
     /** sets a [OnBalloonOutsideTouchListener] to the popup. */
     fun setOnBalloonOutsideTouchListener(value: OnBalloonOutsideTouchListener): Builder = apply {
       this.onBalloonOutsideTouchListener = value
@@ -1239,6 +1250,15 @@ class Balloon(
       }
     }
 
+    /** sets a [OnBalloonInitializedListener] to the popup using lambda. */
+    fun setOnBalloonInitializedListener(unit: (View) -> Unit): Builder = apply {
+      this.onBalloonInitializedListener = object : OnBalloonInitializedListener {
+        override fun onBalloonInitialized(contentView: View) {
+          unit(contentView)
+        }
+      }
+    }
+
     /** sets a [OnBalloonOutsideTouchListener] to the popup using lambda. */
     fun setOnBalloonOutsideTouchListener(unit: (View, MotionEvent) -> Unit): Builder = apply {
       this.onBalloonOutsideTouchListener = object : OnBalloonOutsideTouchListener {

balloon/src/main/java/com/skydoves/balloon/OnBalloonInitializedListener.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2019 skydoves
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.skydoves.balloon
+
+import android.view.View
+
+/** Interface definition for a callback to be invoked when a balloon view is initialized. */
+interface OnBalloonInitializedListener {
+
+  /** invoked when the [Balloon] is initialized. */
+  fun onBalloonInitialized(contentView: View)
+}