1/* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.support.design.widget; 18 19import android.support.v4.view.ViewCompat; 20import android.view.View; 21 22/** 23 * Utility helper for moving a {@link android.view.View} around using 24 * {@link android.view.View#offsetLeftAndRight(int)} and 25 * {@link android.view.View#offsetTopAndBottom(int)}. 26 * <p> 27 * Also the setting of absolute offsets (similar to translationX/Y), rather than additive 28 * offsets. 29 */ 30class ViewOffsetHelper { 31 32 private final View mView; 33 34 private int mLayoutTop; 35 private int mLayoutLeft; 36 private int mOffsetTop; 37 private int mOffsetLeft; 38 39 public ViewOffsetHelper(View view) { 40 mView = view; 41 } 42 43 public void onViewLayout() { 44 // Now grab the intended top 45 mLayoutTop = mView.getTop(); 46 mLayoutLeft = mView.getLeft(); 47 48 // And offset it as needed 49 updateOffsets(); 50 } 51 52 private void updateOffsets() { 53 ViewCompat.offsetTopAndBottom(mView, mOffsetTop - (mView.getTop() - mLayoutTop)); 54 ViewCompat.offsetLeftAndRight(mView, mOffsetLeft - (mView.getLeft() - mLayoutLeft)); 55 } 56 57 /** 58 * Set the top and bottom offset for this {@link ViewOffsetHelper}'s view. 59 * 60 * @param offset the offset in px. 61 * @return true if the offset has changed 62 */ 63 public boolean setTopAndBottomOffset(int offset) { 64 if (mOffsetTop != offset) { 65 mOffsetTop = offset; 66 updateOffsets(); 67 return true; 68 } 69 return false; 70 } 71 72 /** 73 * Set the left and right offset for this {@link ViewOffsetHelper}'s view. 74 * 75 * @param offset the offset in px. 76 * @return true if the offset has changed 77 */ 78 public boolean setLeftAndRightOffset(int offset) { 79 if (mOffsetLeft != offset) { 80 mOffsetLeft = offset; 81 updateOffsets(); 82 return true; 83 } 84 return false; 85 } 86 87 public int getTopAndBottomOffset() { 88 return mOffsetTop; 89 } 90 91 public int getLeftAndRightOffset() { 92 return mOffsetLeft; 93 } 94}