
Android example source code file (DirectionPoint.java)
The DirectionPoint.java Android example source code/* * Copyright (C) 2008 Google Inc. * * 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/LICENSE2.0 * * 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.google.android.divideandconquer; /** * To specify a dividing line, a user hits the screen and drags in a * certain direction. Once the line has been drawn long enough and mostly * in a particular direction (vertical, or horizontal), we can decide we * know what they mean. Otherwise, it is unknown. * * This is also nice because if the user decides they don't want to send * a dividing line, they can just drag their finger back to where they first * touched and let go, cancelling. */ public class DirectionPoint { enum AmbiguousDirection { Vertical, Horizonal, Unknown } private float mX; private float mY; private float endLineX; private float endLineY; public DirectionPoint(float x, float y) { mX = x; mY = y; endLineX = x; endLineY = y; } public void updateEndPoint(float x, float y) { endLineX = x; endLineY = y; } public float getX() { return mX; } public float getY() { return mY; } /** * We know the direction when the line is at leat 20 pixels long, * and the angle is no more than PI / 6 away from a definitive direction. */ public AmbiguousDirection getDirection() { float dx = endLineX  mX; double distance = Math.hypot(dx, endLineY  mY); if (distance < 10) { return AmbiguousDirection.Unknown; } double angle = Math.acos(dx / distance); double thresh = Math.PI / 6; if ((angle < thresh  (angle > (Math.PI  thresh)))) { return AmbiguousDirection.Horizonal; } if ((angle > 2 * thresh) && angle < 4*thresh) { return AmbiguousDirection.Vertical; } return AmbiguousDirection.Unknown; } } Other Android examples (source code examples)Here is a short list of links related to this Android DirectionPoint.java source code file: 
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