| /* |
| * Copyright (C) 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.systemui.util |
| |
| import android.graphics.PointF |
| import android.os.Handler |
| import android.view.MotionEvent |
| import android.view.VelocityTracker |
| import android.view.View |
| import android.view.ViewConfiguration |
| import kotlin.math.hypot |
| |
| /** |
| * Listener which receives [onDown], [onMove], and [onUp] events, with relevant information about |
| * the coordinates of the touch and the view relative to the initial ACTION_DOWN event and the |
| * view's initial position. |
| */ |
| abstract class RelativeTouchListener : View.OnTouchListener { |
| |
| /** |
| * Called when an ACTION_DOWN event is received for the given view. |
| * |
| * @return False if the object is not interested in MotionEvents at this time, or true if we |
| * should consume this event and subsequent events, and begin calling [onMove]. |
| */ |
| abstract fun onDown(v: View, ev: MotionEvent): Boolean |
| |
| /** |
| * Called when an ACTION_MOVE event is received for the given view. This signals that the view |
| * is being dragged. |
| * |
| * @param viewInitialX The view's translationX value when this touch gesture started. |
| * @param viewInitialY The view's translationY value when this touch gesture started. |
| * @param dx Horizontal distance covered since the initial ACTION_DOWN event, in pixels. |
| * @param dy Vertical distance covered since the initial ACTION_DOWN event, in pixels. |
| */ |
| abstract fun onMove( |
| v: View, |
| ev: MotionEvent, |
| viewInitialX: Float, |
| viewInitialY: Float, |
| dx: Float, |
| dy: Float |
| ) |
| |
| /** |
| * Called when an ACTION_UP event is received for the given view. This signals that a drag or |
| * fling gesture has completed. |
| * |
| * @param viewInitialX The view's translationX value when this touch gesture started. |
| * @param viewInitialY The view's translationY value when this touch gesture started. |
| * @param dx Horizontal distance covered, in pixels. |
| * @param dy Vertical distance covered, in pixels. |
| * @param velX The final horizontal velocity of the gesture, in pixels/second. |
| * @param velY The final vertical velocity of the gesture, in pixels/second. |
| */ |
| abstract fun onUp( |
| v: View, |
| ev: MotionEvent, |
| viewInitialX: Float, |
| viewInitialY: Float, |
| dx: Float, |
| dy: Float, |
| velX: Float, |
| velY: Float |
| ) |
| |
| /** The raw coordinates of the last ACTION_DOWN event. */ |
| private val touchDown = PointF() |
| |
| /** The coordinates of the view, at the time of the last ACTION_DOWN event. */ |
| private val viewPositionOnTouchDown = PointF() |
| |
| private val velocityTracker = VelocityTracker.obtain() |
| |
| private var touchSlop: Int = -1 |
| private var movedEnough = false |
| |
| private val handler = Handler() |
| private var performedLongClick = false |
| |
| @Suppress("UNCHECKED_CAST") |
| override fun onTouch(v: View, ev: MotionEvent): Boolean { |
| addMovement(ev) |
| |
| val dx = ev.rawX - touchDown.x |
| val dy = ev.rawY - touchDown.y |
| |
| when (ev.action) { |
| MotionEvent.ACTION_DOWN -> { |
| if (!onDown(v, ev)) { |
| return false |
| } |
| |
| // Grab the touch slop, it might have changed if the config changed since the |
| // last gesture. |
| touchSlop = ViewConfiguration.get(v.context).scaledTouchSlop |
| |
| touchDown.set(ev.rawX, ev.rawY) |
| viewPositionOnTouchDown.set(v.translationX, v.translationY) |
| |
| performedLongClick = false |
| handler.postDelayed({ |
| if (v.isLongClickable) { |
| performedLongClick = v.performLongClick() |
| } |
| }, ViewConfiguration.getLongPressTimeout().toLong()) |
| } |
| |
| MotionEvent.ACTION_MOVE -> { |
| if (!movedEnough && hypot(dx, dy) > touchSlop && !performedLongClick) { |
| movedEnough = true |
| handler.removeCallbacksAndMessages(null) |
| } |
| |
| if (movedEnough) { |
| onMove(v, ev, viewPositionOnTouchDown.x, viewPositionOnTouchDown.y, dx, dy) |
| } |
| } |
| |
| MotionEvent.ACTION_UP -> { |
| if (movedEnough) { |
| velocityTracker.computeCurrentVelocity(1000 /* units */) |
| onUp(v, ev, viewPositionOnTouchDown.x, viewPositionOnTouchDown.y, dx, dy, |
| velocityTracker.xVelocity, velocityTracker.yVelocity) |
| } else if (!performedLongClick) { |
| v.performClick() |
| } else { |
| handler.removeCallbacksAndMessages(null) |
| } |
| |
| velocityTracker.clear() |
| movedEnough = false |
| } |
| } |
| |
| return true |
| } |
| |
| /** |
| * Adds a movement to the velocity tracker using raw screen coordinates. |
| */ |
| private fun addMovement(event: MotionEvent) { |
| val deltaX = event.rawX - event.x |
| val deltaY = event.rawY - event.y |
| event.offsetLocation(deltaX, deltaY) |
| velocityTracker.addMovement(event) |
| event.offsetLocation(-deltaX, -deltaY) |
| } |
| } |