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Diffstat (limited to 'core/src/main/kotlin/ca/allanwang/kau/ui/views/CollapsibleViewDelegate.kt')
| -rw-r--r-- | core/src/main/kotlin/ca/allanwang/kau/ui/views/CollapsibleViewDelegate.kt | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/core/src/main/kotlin/ca/allanwang/kau/ui/views/CollapsibleViewDelegate.kt b/core/src/main/kotlin/ca/allanwang/kau/ui/views/CollapsibleViewDelegate.kt new file mode 100644 index 0000000..6994ca2 --- /dev/null +++ b/core/src/main/kotlin/ca/allanwang/kau/ui/views/CollapsibleViewDelegate.kt @@ -0,0 +1,105 @@ +package ca.allanwang.kau.ui.views + +import android.animation.ValueAnimator +import android.view.View +import ca.allanwang.kau.utils.* +import java.lang.ref.WeakReference + +/** + * Created by Allan Wang on 2017-08-03. + * + * Delegation class for collapsible views + * + * Views that implement this MUST call [initCollapsible] before using any of the methods + * Additionally, you will need to call [getCollapsibleDimension] and use the response for + * [View.setMeasuredDimension] during [View.onMeasure] + * (That method is protected so we cannot access it here) + * + * With reference to <a href="https://github.com/cachapa/ExpandableLayout">ExpandableLayout</a> + */ +interface CollapsibleView { + var expansion: Float + val state: Int + val expanded: Boolean + fun initCollapsible(view: View) + fun resetCollapsibleAnimation() + fun getCollapsibleDimension(): Pair<Int, Int> + fun toggleExpansion() + fun toggleExpansion(animate: Boolean) + fun expand() + fun expand(animate: Boolean) + fun collapse() + fun collapse(animate: Boolean) + fun setExpanded(expand: Boolean) + fun setExpanded(expand: Boolean, animate: Boolean) +} + +class CollapsibleViewDelegate : CollapsibleView { + + private lateinit var viewRef: WeakReference<View> + private val view + get() = viewRef.get() + private var animator: ValueAnimator? = null + + override var expansion = 0f + set(value) { + if (value == field) return + var v = value + if (v > 1) v = 1f + else if (v < 0) v = 0f + stateHolder = + if (v == 0f) KAU_COLLAPSED + else if (v == 1f) KAU_EXPANDED + else if (v - field < 0) KAU_COLLAPSING + else KAU_EXPANDING + field = v + view?.goneIf(state == KAU_COLLAPSED) + view?.requestLayout() + } + + private var stateHolder = KAU_COLLAPSED + override val state + get() = stateHolder + override val expanded + get() = stateHolder == KAU_EXPANDED || stateHolder == KAU_EXPANDING + + override fun initCollapsible(view: View) { + this.viewRef = WeakReference(view) + } + + override fun resetCollapsibleAnimation() { + animator?.cancel() + animator = null + if (stateHolder == KAU_COLLAPSING) stateHolder = KAU_COLLAPSED + else if (stateHolder == KAU_EXPANDING) stateHolder = KAU_EXPANDED + } + + override fun getCollapsibleDimension(): Pair<Int, Int> { + val v = view ?: return Pair(0, 0) + val size = v.measuredHeight + v.goneIf(expansion == 0f && size == 0) + return Pair(v.measuredWidth, Math.round(size * expansion)) + } + + private fun animateSize(target: Float) { + resetCollapsibleAnimation() + animator = ValueAnimator.ofFloat(expansion, target).apply { + addUpdateListener { expansion = it.animatedValue as Float } + start() + } + } + + override fun toggleExpansion() = toggleExpansion(true) + override fun toggleExpansion(animate: Boolean) = setExpanded(!expanded, animate) + override fun expand() = expand(true) + override fun expand(animate: Boolean) = setExpanded(true, animate) + override fun collapse() = collapse(true) + override fun collapse(animate: Boolean) = setExpanded(false, animate) + override fun setExpanded(expand: Boolean) = setExpanded(expand, true) + override fun setExpanded(expand: Boolean, animate: Boolean) { + if (expand == expanded) return //state already matches + val target = if (expand) 1f else 0f + if (animate) animateSize(target) else expansion = target + } + +}
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