Feature/kpref activity visibility (#38)

* Add visibility toggle

* Update docs

5 files changed, 53 insertions, 24 deletions

diff --git a/kpref-activity/README.md b/kpref-activity/README.md
index 015d0d8..a9aac89 100644
--- a/kpref-activity/README.md
+++ b/kpref-activity/README.md
@@ -1,7 +1,14 @@
 # KAU :kpref-activity
 
 KAU supports Preferences that are created without xmls and through AppCompat. 
-The items are backed by a [FastAdapter](https://github.com/mikepenz/FastAdapter) and support [iicons](https://github.com/mikepenz/Android-Iconics)
+The items are backed by a [FastAdapter](https://github.com/mikepenz/FastAdapter) and support [iicons](https://github.com/mikepenz/Android-Iconics).
+The logic behind kpref items is that most states are based around callbacks. 
+As a result, we don't need to hold references of items that may change;
+we simply reload the list and all states will be refetched.
+This is especially powerful when items are interdependent.
+Rather than adding a bunch of calls on one item when its state changes (which we can still do in this lib)
+and propagating to other items when necessary,
+we may instead reload and have each item verify their states themselves.
 
 ![KPref Items Gif](https://raw.githubusercontent.com/AllanWang/Storage-Hub/master/kau/kau_kpref_items.gif)
 
@@ -18,10 +25,11 @@ Contract | Mandatory | Optional | Description
 :--- | :--- | :--- | :---
 `CoreAttributeContract` | `NA` | `textColor` `accentColor` | Defines stylings that are added in every item
 `CoreContract` | `titleRes` | `descRes` `iicon` | Implemented by every item
-`BaseContract` | `getter` `setter` | `enabler` `onClick` `onDisabledClick` | Implemented by every preference item
+`BaseContract` | `getter` `setter` | `enabler` `onClick` `onDisabledClick`, `visible` | Implemented by every preference item
 `KPrefColorContract` | `NA` | `showPreview` | Additional configurations for the color picker
-`KPrefTextContract` | `NA` | `textGetter` | Additional configurations for the text item
+`KPrefSeekbarContract` | `NA` | `min` `max` `increments` `toText` `textViewConfigs` | Addtional configurations for a seekbar, as well as text to be displayed on the side.
 `KPrefSubItemsContract` | `itemBuilder` | `NA` | Contains a new list for the adapter to load when clicked
+`KPrefTextContract` | `NA` | `textGetter` | Additional configurations for the text item
 
 The kpref items are as followed:
 
@@ -29,9 +37,10 @@ Item | Implements | Description
 :--- | :--- | :---
 `checkbox` | `CoreContract` `BaseContract` | Checkbox item; by default, clicking it will toggle the checkbox and the kpref
 `colorPicker` | `CoreContract` `BaseContract` `KPrefColorContract` | Color picker item; by default, clicking it will open a dialog which will change the color (int)
+`seekbar` | `CoreContract` `BaseContract` `KprefSeekbarContract` | Seekbar item. Takes in a given range and will call the setter whenever a user picks a new value.
 `header` | `CoreContract` | Header; just a title that isn't clickable
 `text` | `CoreContract` `BaseContract` `KPrefTextContract` | Text item; displays the kpref as a String on the right; does not have click implementation by default
-`plainText` | `BaseContract` | Plain text item; like `text` but does not deal with any preferences directly, so it doesn't need a getter or setter
+`plainText` | `CoreContract` `BaseContract` | Plain text item; like `text` but does not deal with any preferences directly, so it doesn't need a getter or setter
 This can be used to display text or deal with preference that are completely handed within the click event (eg a dialog).
 `subItems` | `CoreContract` `KPrefSubItemsContract` | Sub items; contains a new page for the activity to load when clicked
  
diff --git a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefActivity.kt b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefActivity.kt
index 900b004..4377631 100644
--- a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefActivity.kt
+++ b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefActivity.kt
@@ -85,26 +85,57 @@ abstract class KPrefActivity : KauBaseActivity(), KPrefActivityContract {
             recycler.itemAnimator = if (animate && !first) recyclerAnimatorNext else null
             uiThread {
                 adapter.clear()
-                adapter.add(items.list)
+                adapter.add(items.list.filter { it.core.visible() })
                 toolbar.setTitle(toolbarTitleRes)
             }
         }
     }
 
+    /**
+     * Pops the stack and loads the next kpref list
+     * Indices are not checked so ensure that this is possible first
+     */
     override fun showPrevPrefs() {
         kprefStack.pop()
         val (title, list) = kprefStack.peek()
         recycler.itemAnimator = if (animate) recyclerAnimatorPrev else null
         adapter.clear()
-        adapter.add(list)
+        adapter.add(list.filter { it.core.visible() })
         toolbar.setTitle(title)
     }
 
+    /**
+     * Check if it's possible to go back a stack
+     */
+    override val hasPrevPrefs
+        get() = kprefStack.size > 1
+
+    /**
+     * Reload the current pref list from the stack.
+     * This will adjust the list of items change in visibility
+     */
+    fun reloadList() {
+        recycler.itemAnimator = null
+        val list = kprefStack.peek().second
+        adapter.setNewList(list.filter { it.core.visible() })
+    }
+
+    /**
+     * Selectively reload an item based on its index.
+     * Note that this might not behave as expected if certain items are not visible,
+     * as those items aren't sent to the adapter.
+     *
+     * For those cases, consider using [reloadByTitle]
+     */
     fun reload(vararg index: Int) {
         if (index.isEmpty()) adapter.notifyAdapterDataSetChanged()
         else index.forEach { adapter.notifyItemChanged(it) }
     }
 
+    /**
+     * Iterate through all items and reload if it matches any of the titles
+     * If multiple items have the same title, they will all be reloaded
+     */
     override fun reloadByTitle(@StringRes vararg title: Int) {
         if (title.isEmpty()) return
         adapter.adapterItems.forEachIndexed { index, item ->
@@ -120,7 +151,7 @@ abstract class KPrefActivity : KauBaseActivity(), KPrefActivityContract {
     }
 
     fun backPress(): Boolean {
-        if (kprefStack.size > 1) {
+        if (hasPrevPrefs) {
             showPrevPrefs()
             return true
         }
diff --git a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefBinder.kt b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefBinder.kt
index b45e406..35821fd 100644
--- a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefBinder.kt
+++ b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/KPrefBinder.kt
@@ -30,6 +30,7 @@ class CoreAttributeBuilder : CoreAttributeContract {
 
 interface KPrefActivityContract {
     fun showNextPrefs(@StringRes toolbarTitleRes: Int, builder: KPrefAdapterBuilder.() -> Unit)
+    val hasPrevPrefs: Boolean
     fun showPrevPrefs()
     fun reloadByTitle(@StringRes vararg title: Int)
 }
diff --git a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefItemCore.kt b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefItemCore.kt
index 96f8903..dc74c97 100644
--- a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefItemCore.kt
+++ b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefItemCore.kt
@@ -84,6 +84,7 @@ abstract class KPrefItemCore(val core: CoreContract) : AbstractItem<KPrefItemCor
         var descRes: Int
             @StringRes get
         var iicon: IIcon?
+        var visible: () -> Boolean
 
         /**
          * Attempts to reload current item by identifying it with its [titleRes]
@@ -98,6 +99,7 @@ abstract class KPrefItemCore(val core: CoreContract) : AbstractItem<KPrefItemCor
                       override @param:StringRes val titleRes: Int) : CoreContract {
         override var descRes: Int = -1
         override var iicon: IIcon? = null
+        override var visible: () -> Boolean = { true }
 
         override fun reloadSelf() {
             globalOptions.reloadByTitle(titleRes)
diff --git a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefSeekbar.kt b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefSeekbar.kt
index f161382..6a9f6b0 100644
--- a/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefSeekbar.kt
+++ b/kpref-activity/src/main/kotlin/ca/allanwang/kau/kpref/activity/items/KPrefSeekbar.kt
@@ -28,7 +28,7 @@ open class KPrefSeekbar(val builder: KPrefSeekbarContract) : KPrefItemBase<Int>(
 
         text.tvc()
         val seekbar = viewHolder.bindLowerView<SeekBar>(R.layout.kau_pref_seekbar) {
-            it.max = builder.range
+            it.max = builder.max - builder.min
             it.incrementProgressBy(builder.increments)
             it.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
                 override fun onProgressChanged(sb: SeekBar, progress: Int, fromUser: Boolean) {
@@ -55,7 +55,6 @@ open class KPrefSeekbar(val builder: KPrefSeekbarContract) : KPrefItemBase<Int>(
         var min: Int
         var max: Int
         var increments: Int
-        var range: Int
         /**
          * Once a seekbar is let go, calculates what text to show in the text view
          */
@@ -74,23 +73,10 @@ open class KPrefSeekbar(val builder: KPrefSeekbarContract) : KPrefItemBase<Int>(
     ) : KPrefSeekbarContract, BaseContract<Int> by BaseBuilder(globalOptions, titleRes, getter, setter) {
 
         override var min: Int = 0
-            set(value) {
-                field = value
-                range = -1
-            }
+
         override var max: Int = 100
-            set(value) {
-                field = value
-                range = -1
-            }
-        override var increments: Int = 1
 
-        override var range: Int = max - min
-                //value doesn't matter; setting will prompt the check
-            set(value) {
-                if (max <= min) throw KPrefException("Range min ($min) must be smaller than max ($max)")
-                field = max - min
-            }
+        override var increments: Int = 1
 
         override var toText: (Int) -> String = { it.toString() }