1 files changed, 85 insertions, 0 deletions
diff --git a/core/src/main/kotlin/ca/allanwang/kau/ui/ProgressAnimator.kt b/core/src/main/kotlin/ca/allanwang/kau/ui/ProgressAnimator.kt
new file mode 100644
index 0000000..dc10e71
--- /dev/null
+++ b/core/src/main/kotlin/ca/allanwang/kau/ui/ProgressAnimator.kt
@@ -0,0 +1,85 @@
+package ca.allanwang.kau.ui
+
+import android.animation.Animator
+import android.animation.AnimatorListenerAdapter
+import android.animation.ValueAnimator
+import android.view.animation.Interpolator
+
+/**
+ * Created by Allan Wang on 2017-11-10.
+ *
+ * Wrapper for value animator specifically dealing with progress values
+ * This is typically a float range of 0 to 1, but can be customized
+ * This differs in that everything can be done with simple listeners, which will be bundled
+ * and added to the backing [ValueAnimator]
+ */
+class ProgressAnimator private constructor(private vararg val values: Float) {
+
+    companion object {
+        inline fun ofFloat(crossinline builder: ProgressAnimator.() -> Unit) = ofFloat(0f, 1f) { builder() }
+
+        fun ofFloat(vararg values: Float, builder: ProgressAnimator.() -> Unit) = ProgressAnimator(*values).apply {
+            builder()
+            build()
+        }
+    }
+
+    private val animators: MutableList<(Float) -> Unit> = mutableListOf()
+    private val startActions: MutableList<() -> Unit> = mutableListOf()
+    private val endActions: MutableList<() -> Unit> = mutableListOf()
+
+    var duration: Long = -1L
+    var interpolator: Interpolator? = null
+
+    /**
+     * Add more changes to the [ValueAnimator] before running
+     */
+    var extraConfigs: ValueAnimator.() -> Unit = {}
+
+    /**
+     * Range animator. Multiples the range by the current float progress before emission
+     */
+    fun withAnimator(from: Float, to: Float, animator: (Float) -> Unit) = animators.add {
+        val range = to - from
+        animator(range * it + from)
+    }
+
+    /**
+     * Standard animator. Emits progress value as is
+     */
+    fun withAnimator(animator: (Float) -> Unit) = animators.add(animator)
+
+    /**
+     * Start action to be called once when the animator first begins
+     */
+    fun withStartAction(action: () -> Unit) = startActions.add(action)
+
+    /**
+     * End action to be called once when the animator ends
+     */
+    fun withEndAction(action: () -> Unit) = endActions.add(action)
+
+    fun build() {
+        ValueAnimator.ofFloat(*values).apply {
+            if (this@ProgressAnimator.duration > 0L)
+                duration = this@ProgressAnimator.duration
+            if (this@ProgressAnimator.interpolator != null)
+                interpolator = this@ProgressAnimator.interpolator
+            addUpdateListener {
+                val progress = it.animatedValue as Float
+                animators.forEach { it(progress) }
+            }
+            addListener(object : AnimatorListenerAdapter() {
+                override fun onAnimationStart(animation: Animator?) {
+                    startActions.forEach { it() }
+                }
+
+                override fun onAnimationEnd(animation: Animator?) {
+                    endActions.forEach { it() }
+                }
+            })
+            extraConfigs()
+            start()
+        }
+    }
+}
+\ No newline at end of file