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fenix/app/src/main/java/org/mozilla/fenix/browser/BrowserToolbarTopBehavior.kt

121 lines
4.1 KiB
Kotlin

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.fenix.browser
import android.animation.ValueAnimator
import android.content.Context
import android.util.AttributeSet
import android.view.Gravity
import android.view.View
import android.view.View.SCROLL_AXIS_VERTICAL
import android.view.animation.DecelerateInterpolator
import androidx.coordinatorlayout.widget.CoordinatorLayout
import androidx.core.view.ViewCompat.TYPE_NON_TOUCH
import androidx.core.view.ViewCompat.TYPE_TOUCH
import com.google.android.material.snackbar.Snackbar
import mozilla.components.browser.toolbar.BrowserToolbar
import org.mozilla.fenix.R
import kotlin.math.max
import kotlin.math.min
private const val SNAP_ANIMATION_DURATION = 150L
/**
* A [CoordinatorLayout.Behavior] implementation to be used when placing [BrowserToolbar] at the top of the screen.
*
* This implementation will:
* - Show/Hide the [BrowserToolbar] automatically when scrolling vertically.
* - On showing a [Snackbar] position it above the [BrowserToolbar].
* - Snap the [BrowserToolbar] to be hidden or visible when the user stops scrolling.
*/
class BrowserToolbarTopBehavior(
context: Context?,
attrs: AttributeSet?
) : CoordinatorLayout.Behavior<BrowserToolbar>(context, attrs) {
// This implementation is heavily based on this blog article:
// https://android.jlelse.eu/scroll-your-bottom-navigation-view-away-with-10-lines-of-code-346f1ed40e9e
internal var shouldSnapAfterScroll: Boolean = false
internal var snapAnimator: ValueAnimator = ValueAnimator().apply {
interpolator = DecelerateInterpolator()
duration = SNAP_ANIMATION_DURATION
}
fun forceExpand(view: View) {
animateSnap(view, SnapDirection.DOWN)
}
override fun onStartNestedScroll(
coordinatorLayout: CoordinatorLayout,
child: BrowserToolbar,
directTargetChild: View,
target: View,
axes: Int,
type: Int
): Boolean {
return if (axes == SCROLL_AXIS_VERTICAL) {
shouldSnapAfterScroll = type == TYPE_TOUCH
snapAnimator.cancel()
true
} else {
false
}
}
override fun onStopNestedScroll(
coordinatorLayout: CoordinatorLayout,
child: BrowserToolbar,
target: View,
type: Int
) {
if (shouldSnapAfterScroll || type == TYPE_NON_TOUCH) {
if (child.translationY >= (-child.height / 2f)) {
animateSnap(child, SnapDirection.DOWN)
} else {
animateSnap(child, SnapDirection.UP)
}
}
}
override fun onNestedPreScroll(
coordinatorLayout: CoordinatorLayout,
child: BrowserToolbar,
target: View,
dx: Int,
dy: Int,
consumed: IntArray,
type: Int
) {
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type)
child.translationY = max(-child.height.toFloat(), min(0f, child.translationY - dy))
}
override fun layoutDependsOn(parent: CoordinatorLayout, child: BrowserToolbar, dependency: View): Boolean {
if (dependency is Snackbar.SnackbarLayout) {
positionSnackbar(dependency)
}
return super.layoutDependsOn(parent, child, dependency)
}
private fun animateSnap(child: View, direction: SnapDirection) = with(snapAnimator) {
addUpdateListener { child.translationY = it.animatedValue as Float }
setFloatValues(child.translationY, if (direction == SnapDirection.DOWN) 0f else -child.height.toFloat())
start()
}
private fun positionSnackbar(view: View) {
val params = view.layoutParams as CoordinatorLayout.LayoutParams
// Position the snackbar below the toolbar so that it doesn't overlay the toolbar.
params.anchorId = R.id.toolbar
params.anchorGravity = Gravity.BOTTOM or Gravity.CENTER_HORIZONTAL
params.gravity = Gravity.BOTTOM or Gravity.CENTER_HORIZONTAL
view.layoutParams = params
}
}