Improve callbacks access through Listener class

README.md

@@ -1,11 +1,10 @@
 # progress-indicator-view
-A custom Android view showing determinate progress through a stupid but funny animation.
+A custom Android view showing determinate progress through a fun/stupid animation.
 
-There are a lot of cool animations for indeterminate progress bars, but there are not many ways to add a little fun to determinate progress bars. We needed a progress bar to show the download state of a [Dynamic Module](https://developer.android.com/studio/projects/dynamic-delivery). The designer working with me thought that the awesome Android 6 [boot animation](https://www.youtube.com/watch?v=8TGC6EmVXlU) shows the current progress of boot, and she asked me to replicate it. While that's not correct, I was intrigued by the idea and this is the result.
-I did nothing more than extending romandanylyk's [PageIndicatorView](https://github.com/romandanylyk/PageIndicatorView), adding similar setters and getters to Android [ProgressBar](https://developer.android.com/reference/android/widget/ProgressBar), and implementing a [finite-state machine](https://en.wikipedia.org/wiki/Finite-state_machine) to manage the animation while progressing.
+There are a lot of cool animations for indeterminate progress bars, but there are not many ways to add a little fun to determinate progress bars. I did nothing more than extending romandanylyk's [PageIndicatorView](https://github.com/romandanylyk/PageIndicatorView), adding similar setters and getters to Android [ProgressBar](https://developer.android.com/reference/android/widget/ProgressBar), and implementing a [finite-state machine](https://en.wikipedia.org/wiki/Finite-state_machine) to manage the animation while progressing.
 
-![exmaple Shenzen](docs/gifs/Progress_Indicator_View_Example_2019-07-01-14-57-22.gif)
-![example Shenyang](docs/gifs/Progress_Indicator_View_Example_2019-07-01-14-58-38.gif)
+![exmaple Shenzen](docs/gifs/Progress_Indicator_View_Example_2019-07-03-09-41-26.gif)
+![example Shenyang](docs/gifs/Progress_Indicator_View_Example_2019-07-03-09-42-41.gif)
 
 ## Download   [![Release](https://jitpack.io/v/eu.acolombo/progress-indicator-view.svg)](https://jitpack.io/#eu.acolombo/progress-indicator-view)
 
@@ -27,17 +26,58 @@ allprojects {
 
 This library is AndroidX only, if you are still using Support libraries you can either migrate your app to AndroidX or you can contribute by downgrading the dependencies and subitting a pull-request, which will be merged in a different branch.
 
-## Customization
+## Usage
 
-All [PageIndicatorView](https://github.com/romandanylyk/PageIndicatorView)'s attributes are still valid and can be used both through Java/Kotlin and through XML. I also added a few more similar to ProgressBar's ones and a few more which I'll explain/illustrate later.
+See [PageIndicatorView](https://github.com/romandanylyk/PageIndicatorView)'s README, all the `piv_` attributes attributes are still valid (I wouldn't attach it to a ViewPager though) and in the sample below I used the most relevant ones.
 
-    stopOnStep
-    stepToMin
-    skipSteps
-    balanceForward
+```xml
+<eu.acolombo.progressindicatorview.ProgressIndicatorView
+    android:id="@+id/progressIndicatorView"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    app:piv_min="100"
+    app:piv_max="100"
+    app:piv_progress="0"
+    app:piv_count="8"
+    app:piv_radius="4dp"
+    app:piv_padding="16dp"
+    app:piv_animationDuration="200"
+    app:piv_animationType="slide"
+    app:piv_selectedColor="@color/colorPrimary"
+    app:piv_unselectedColor="@color/colorPrimaryDark" />
+```
+
+There are also a few `ProgressIndicatorView` specific attributes. They can be accessed in XML under the same prefix, `piv_`, and in kotlin/java through their respective getters/setters. The first group of attributes replicate the `ProgressBar`'ones, while the following are all flags defining the behavior of the component:
+
+name             | format  | default | description
+---------------- | ------- | ------- | ------------------
+`min`            | integer | 0       | Same as `ProgressBar` `min`. Defines the minimum value.  
+`max`            | integer | 100     | Same as `ProgressBar` `max`. Defines the maximum value.  
+`progress`       | integer | 0       | Same as `ProgressBar` `max`. Defines the default progress value, between min and max.  
+`stopOnStep`     | boolean | false   | When the `progress` is exactly between steps, the animation stops.
+`stopOnStart`    | boolean | true    | When the `progress` is the same as the starting limit, the animation stops. This limit is `min` if `balanceForward` is true, `max` otherwise.
+`stepToMin`      | boolean | false   | The animation always goes back to the first step instead of going back to the previous one.
+`skipSteps`      | boolean | false   | If the `progress` is faster than the animation, the animation will catch up by skipping steps. *Use `setProgress(progress: Int, animate: Boolean)` if you want to skip the animation altogether.*
+`balanceForward` | boolean | true    | Defines the direction of the animation when the `progress` is between the two central steps (i.e. 50 with a max of 100). *Not valid when the progress is going up and down because the direction of the progress is more signficant, but it still affects `stopOnStart` as explained above.*
 
 I also added three callbacks:
 
-    onStepChanged
-    onMinReached
-    onMaxReached
++onStepChanged
++onMinReached
++onMaxReached
+
+I'm sorry for Java users since I didn't use the usual Listener interface to implement. I made it in a more functional way to be faster and cleaner to use in kotlin.
+
+Their names are self explanatory and you can use them in two ways. If you want to use more than one, use the constructor for `ProgressIndicatorView.Listener`:
+```kotlin
+progressIndicatorView.listener = ProgressIndicatorView.Listener(
+    onMaxReached = { Log.d(TAG, "max" ) },
+    onStepChanged = { step, forward -> Log.d(TAG, "$step $forward" ) },
+    onMinReached = { Log.d(TAG, "min" ) }
+)
+```
+Otherwise just redefine one of them or each at a time:
+```kotlin
+progressIndicatorView.listener.onMaxReached = { Log.d(TAG, "max" ) }
+```
+<small>*I'd like to receive some feedbacks for this choice I made and how I decided to tackle it, so if you're reading this go check out the [implementation](https://github.com/acolombo25/progress-indicator-view/blob/master/progress-indicator-view/src/main/java/eu/acolombo/progressindicatorview/ProgressIndicatorView.kt#L16) and let me know what you think.*</small>

app/src/main/java/eu/acolombo/progressindicatorview/example/BaseFragment.kt

@@ -8,6 +8,7 @@ import android.util.Log
 import android.view.View
 import android.widget.SeekBar
 import androidx.fragment.app.Fragment
+import eu.acolombo.progressindicatorview.ProgressIndicatorView
 import kotlinx.android.synthetic.main.fragment_shenzen.*
 import kotlin.random.Random
 
@@ -23,9 +24,13 @@ abstract class BaseFragment : Fragment() {
         textMax?.text = "${progressIndicatorView.max}%"
         textMin?.text = "${progressIndicatorView.min}%"
 
-        progressIndicatorView.onMaxReached = { Log.d(javaClass.name, "MAX" ) }
-        progressIndicatorView.onStepChanged = { step, forward -> Log.d(javaClass.name, "$step $forward" ) }
-        progressIndicatorView.onMinReached = { Log.d(javaClass.name, "MIN" ) }
+        progressIndicatorView.listener = ProgressIndicatorView.Listener(
+            onMaxReached = { Log.d(javaClass.name, "MAX" ) },
+            onStepChanged = { step, forward -> Log.d(javaClass.name, "$step $forward" ) },
+            onMinReached = { Log.d(javaClass.name, "MIN" ) }
+        )
+
+        progressIndicatorView.listener.onMaxReached = { Log.d(javaClass.name, "MAX" ) }
     }
 
     fun setupProgress(progress: Int) {
@@ -68,6 +73,11 @@ abstract class BaseFragment : Fragment() {
             }
         }
 
+        textProgress.setOnLongClickListener {
+            setupProgress(0)
+            true
+        }
+
         val animator = ValueAnimator()
         val random = Random(69)
         val randomUnit = 60

progress-indicator-view/src/main/java/eu/acolombo/progressindicatorview/ProgressIndicatorView.kt

@@ -13,6 +13,14 @@ class ProgressIndicatorView @JvmOverloads constructor(
     defStyleAttr: Int = 0
 ) : PageIndicatorView(context, attrs, defStyleAttr) {
 
+    class Listener(
+        var onStepChanged: (step: Int, forward: Boolean) -> Unit = { _, _ -> },
+        var onMinReached: () -> Unit = { },
+        var onMaxReached: () -> Unit = { }
+    )
+
+    var listener = Listener()
+
     private val typedArray: TypedArray = context.obtainStyledAttributes(attrs, R.styleable.ProgressIndicatorView)
     var progress = typedArray.getInt(R.styleable.ProgressIndicatorView_piv_progress, 0)
     var min = typedArray.getInt(R.styleable.ProgressIndicatorView_piv_min, 0)
@@ -24,10 +32,6 @@ class ProgressIndicatorView @JvmOverloads constructor(
     var skipSteps: Boolean = typedArray.getBoolean(R.styleable.ProgressIndicatorView_piv_skipSteps, false)
     var balanceForward: Boolean = typedArray.getBoolean(R.styleable.ProgressIndicatorView_piv_balanceForward, true)
 
-    var onStepChanged: (step: Int, forward: Boolean) -> Unit = { _, _ -> }
-    var onMinReached: () -> Unit = { }
-    var onMaxReached: () -> Unit = { }
-
     fun setProgress(progress: Int, animate: Boolean) {
         this.progress = progress
         if (!animate) setSelected(stepProgress)
@@ -72,9 +76,9 @@ class ProgressIndicatorView @JvmOverloads constructor(
                         selection != stepProgress - 1 && skipSteps -> {
                             selection = stepProgress - 1
                             when (progress) {
-                                min -> onMinReached()
-                                max -> onMaxReached()
-                                else -> onStepChanged(selection + 1, step < selection +1)
+                                min -> listener.onMinReached()
+                                max -> listener.onMaxReached()
+                                else -> listener.onStepChanged(selection + 1, step < selection +1)
                             }
                         }
                     }
@@ -85,7 +89,7 @@ class ProgressIndicatorView @JvmOverloads constructor(
                     state = if ((progress < next || statePrev == State.BACKWARD && progress <= next) && !stopOnThisStep) {
                         State.BACKWARD
                     } else {
-                        if (step < count - 1) onStepChanged(++step, true) else onMaxReached()
+                        if (step < count - 1) listener.onStepChanged(++step, true) else listener.onMaxReached()
                         statePrev = state
                         State.STOP
                     }
@@ -96,7 +100,7 @@ class ProgressIndicatorView @JvmOverloads constructor(
                     state = if ((progress > prev || statePrev == State.FORWARD && progress >= prev) && !stopOnThisStep) {
                         State.FORWARD
                     } else {
-                        if (step > 1) onStepChanged(--step, false) else onMinReached()
+                        if (step > 1) listener.onStepChanged(--step, false) else listener.onMinReached()
                         statePrev = state
                         State.STOP
                     }