a53b3983bf
PiperOrigin-RevId: 210155157 Change-Id: I707512aab6ac57aaebb93275669ae16b92b0e66d
110 lines
3.8 KiB
Java
110 lines
3.8 KiB
Java
/*
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* Copyright (C) 2016 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.setupwizardlib.gesture;
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import android.graphics.Rect;
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import android.view.MotionEvent;
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import android.view.View;
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import android.view.ViewConfiguration;
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/**
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* Helper class to detect the consective-tap gestures on a view.
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*
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* <p>This class is instantiated and used similar to a GestureDetector, where onTouchEvent should be
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* called when there are MotionEvents this detector should know about.
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*/
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public final class ConsecutiveTapsGestureDetector {
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public interface OnConsecutiveTapsListener {
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/** Callback method when the user tapped on the target view X number of times. */
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void onConsecutiveTaps(int numOfConsecutiveTaps);
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}
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private final View view;
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private final OnConsecutiveTapsListener listener;
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private final int consecutiveTapTouchSlopSquare;
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private final int consecutiveTapTimeout;
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private int consecutiveTapsCounter = 0;
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private MotionEvent previousTapEvent;
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/**
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* @param listener The listener that responds to the gesture.
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* @param view The target view that associated with consecutive-tap gesture.
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*/
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public ConsecutiveTapsGestureDetector(OnConsecutiveTapsListener listener, View view) {
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this.listener = listener;
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this.view = view;
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int doubleTapSlop = ViewConfiguration.get(this.view.getContext()).getScaledDoubleTapSlop();
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consecutiveTapTouchSlopSquare = doubleTapSlop * doubleTapSlop;
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consecutiveTapTimeout = ViewConfiguration.getDoubleTapTimeout();
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}
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/**
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* This method should be called from the relevant activity or view, typically in onTouchEvent,
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* onInterceptTouchEvent or dispatchTouchEvent.
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*
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* @param ev The motion event
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*/
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public void onTouchEvent(MotionEvent ev) {
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if (ev.getAction() == MotionEvent.ACTION_UP) {
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Rect viewRect = new Rect();
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int[] leftTop = new int[2];
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view.getLocationOnScreen(leftTop);
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viewRect.set(
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leftTop[0], leftTop[1], leftTop[0] + view.getWidth(), leftTop[1] + view.getHeight());
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if (viewRect.contains((int) ev.getX(), (int) ev.getY())) {
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if (isConsecutiveTap(ev)) {
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consecutiveTapsCounter++;
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} else {
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consecutiveTapsCounter = 1;
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}
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listener.onConsecutiveTaps(consecutiveTapsCounter);
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} else {
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// Touch outside the target view. Reset counter.
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consecutiveTapsCounter = 0;
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}
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if (previousTapEvent != null) {
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previousTapEvent.recycle();
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}
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previousTapEvent = MotionEvent.obtain(ev);
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}
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}
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/** Resets the consecutive-tap counter to zero. */
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public void resetCounter() {
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consecutiveTapsCounter = 0;
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}
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/**
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* Returns true if the distance between consecutive tap is within {@link
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* #consecutiveTapTouchSlopSquare}. False, otherwise.
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*/
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private boolean isConsecutiveTap(MotionEvent currentTapEvent) {
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if (previousTapEvent == null) {
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return false;
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}
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double deltaX = previousTapEvent.getX() - currentTapEvent.getX();
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double deltaY = previousTapEvent.getY() - currentTapEvent.getY();
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long deltaTime = currentTapEvent.getEventTime() - previousTapEvent.getEventTime();
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return (deltaX * deltaX + deltaY * deltaY <= consecutiveTapTouchSlopSquare)
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&& deltaTime < consecutiveTapTimeout;
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}
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}
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