Java tutorial
//package com.java2s; /* * Copyright (C) 2016 Zheng Li <https://lizheng.me> * Copyright (C) 2014 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. */ import android.view.View; import java.util.ArrayList; public class Main { /** * Maps a coordinate in a descendant view into the parent. */ public static float mapCoordInDescendentToSelf(View descendant, View root, float[] coord, boolean includeRootScroll) { ArrayList<View> ancestorChain = new ArrayList<>(); float[] pt = { coord[0], coord[1] }; View v = descendant; while (v != root && v != null) { ancestorChain.add(v); v = (View) v.getParent(); } ancestorChain.add(root); float scale = 1.0f; int count = ancestorChain.size(); for (int i = 0; i < count; i++) { View v0 = ancestorChain.get(i); // For TextViews, scroll has a meaning which relates to the text position // which is very strange... ignore the scroll. if (v0 != descendant || includeRootScroll) { pt[0] -= v0.getScrollX(); pt[1] -= v0.getScrollY(); } v0.getMatrix().mapPoints(pt); pt[0] += v0.getLeft(); pt[1] += v0.getTop(); scale *= v0.getScaleX(); } coord[0] = pt[0]; coord[1] = pt[1]; return scale; } }