Add styleable attributes for setting padding by percentage and dp

Author: hendrawd

README.md

@@ -31,14 +31,22 @@ private fun initDeck() {
 
 or set padding based on percentage of the screen width
 
-```kotlin
-deckPager.setPercentagePadding(activity)
+```
+// in kotlin
+deckPager.setPercentagePadding(activity, 8)
+
+// in XML
+app:padding_percentage="8"
 ```
 
 or set padding based on dp value
 
-```kotlin
-deckPager.setDpPadding(activity)
+```
+// in kotlin
+deckPager.setDpPadding(activity, 16)
+
+// in XML
+app:padding_dp="16dp"
 ```
 
 ##### Remember you can set all other view pager properties with deck

app/src/main/res/layout/activity_main.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<RelativeLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
@@ -9,6 +10,7 @@
         android:id="@+id/deck_pager"
         android:layout_width="match_parent"
         android:layout_height="400dp"
-        android:layout_centerInParent="true"/>
+        android:layout_centerInParent="true"
+        />
 
 </RelativeLayout>

lib/src/main/java/com/example/lib/Deck.kt

@@ -2,6 +2,7 @@ package com.example.lib
 
 import android.app.Activity
 import android.content.Context
+import android.content.res.TypedArray
 import android.support.v4.view.ViewPager
 import android.util.AttributeSet
 import android.util.DisplayMetrics
@@ -17,7 +18,19 @@ class Deck : ViewPager {
     private val pageTransformer = CoverFlowTransformer()
 
     constructor(context: Context) : super(context)
-    constructor(context: Context, attributeSet: AttributeSet) : super(context, attributeSet)
+
+    constructor(context: Context, attributeSet: AttributeSet) : super(context, attributeSet) {
+        val typedArray: TypedArray = context.obtainStyledAttributes(attributeSet, R.styleable.Deck)
+        val percentagePaddingXml = typedArray.getInt(R.styleable.Deck_padding_percentage, Integer.MAX_VALUE)
+        if (percentagePaddingXml != Integer.MAX_VALUE) {
+            setPercentagePadding(context, percentagePaddingXml)
+        }
+        val dipPaddingXmlInPixel = typedArray.getDimensionPixelSize(R.styleable.Deck_padding_dp, Integer.MAX_VALUE)
+        if (dipPaddingXmlInPixel != Integer.MAX_VALUE) {
+            initProperties(context, dipPaddingXmlInPixel.toFloat())
+        }
+        typedArray.recycle()
+    }
 
     init {
         initView()
@@ -30,22 +43,22 @@ class Deck : ViewPager {
     /**
      * Set left and right padding with default value
      */
-    fun setDefaultPadding(context: Activity) {
+    fun setDefaultPadding(context: Context) {
         setPercentagePadding(context, DEFAULT_PERCENTAGE_PADDING)
     }
 
     /**
      * Set left and right padding based on percentage of the screen width
      * If the percentage is more than 18, the left and right items height might not be consistent
      */
-    fun setPercentagePadding(context: Activity, percentage: Int) {
+    fun setPercentagePadding(context: Context, percentage: Int) {
         when {
             percentage == 0 -> initProperties(context, 0f)
             percentage < 0 -> throw IllegalArgumentException("Percentage can't be lower than 0")
             percentage > 100 -> throw IllegalArgumentException("Percentage can't be higher than 100")
             else -> {
                 val metrics = DisplayMetrics()
-                context.windowManager.defaultDisplay.getMetrics(metrics)
+                (context as Activity).windowManager.defaultDisplay.getMetrics(metrics)
                 val padding = metrics.widthPixels * percentage / 100f
                 initProperties(context, padding)
             }
@@ -55,7 +68,7 @@ class Deck : ViewPager {
     /**
      * Set left and right padding based on dp value
      */
-    fun setDpPadding(context: Activity, dp: Float) {
+    fun setDpPadding(context: Context, dp: Float) {
         val padding = TypedValue.applyDimension(
                 TypedValue.COMPLEX_UNIT_DIP,
                 dp,
@@ -64,14 +77,14 @@ class Deck : ViewPager {
         initProperties(context, padding)
     }
 
-    private fun initProperties(context: Activity, padding: Float) {
+    private fun initProperties(context: Context, padding: Float) {
         val intPadding = padding.toInt()
         setPadding(intPadding, 0, intPadding, 0)
         clipToPadding = false
         pageMargin = 0
 
         val metrics = DisplayMetrics()
-        context.windowManager.defaultDisplay.getMetrics(metrics)
+        (context as Activity).windowManager.defaultDisplay.getMetrics(metrics)
         pageTransformer.paddingFactor = padding / metrics.widthPixels
     }
 }

lib/src/main/res/values/attrs.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <declare-styleable name="Deck">
+        <attr name="padding_percentage" format="integer"/>
+        <attr name="padding_dp" format="dimension"/>
+    </declare-styleable>
+</resources>