1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14package android.support.v17.leanback.widget; 15 16import android.graphics.Rect; 17import android.support.v4.view.ViewCompat; 18import android.view.View; 19import android.view.View.MeasureSpec; 20import android.view.ViewGroup; 21import android.view.ViewGroup.MarginLayoutParams; 22 23/** 24 * A helper class for showing a hover card view below a {@link HorizontalGridView}. The hover card 25 * is aligned to the starting edge of the selected child view. If there is no space when scrolling 26 * to the end, the ending edge of the hover card will be aligned to the ending edge of the parent 27 * view, excluding padding. 28 */ 29public final class HorizontalHoverCardSwitcher extends PresenterSwitcher { 30 // left and right of selected card view 31 int mCardLeft, mCardRight; 32 33 private int[] mTmpOffsets = new int[2]; 34 private Rect mTmpRect = new Rect(); 35 36 @Override 37 protected void insertView(View view) { 38 // append hovercard to the end of container 39 getParentViewGroup().addView(view); 40 } 41 42 @Override 43 protected void onViewSelected(View view) { 44 int rightLimit = getParentViewGroup().getWidth() - getParentViewGroup().getPaddingRight(); 45 int leftLimit = getParentViewGroup().getPaddingLeft(); 46 // measure the hover card width; if it's too large, align hover card 47 // end edge with row view's end edge, otherwise align start edges. 48 view.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED); 49 MarginLayoutParams params = (MarginLayoutParams) view.getLayoutParams(); 50 boolean isRtl = ViewCompat.getLayoutDirection(view) == View.LAYOUT_DIRECTION_RTL; 51 if (!isRtl && mCardLeft + view.getMeasuredWidth() > rightLimit) { 52 params.leftMargin = rightLimit - view.getMeasuredWidth(); 53 } else if (isRtl && mCardLeft < leftLimit) { 54 params.leftMargin = leftLimit; 55 } else if (isRtl) { 56 params.leftMargin = mCardRight - view.getMeasuredWidth(); 57 } else { 58 params.leftMargin = mCardLeft; 59 } 60 view.requestLayout(); 61 } 62 63 /** 64 * Select a childView inside a grid view and create/bind a corresponding hover card view 65 * for the object. 66 */ 67 public void select(HorizontalGridView gridView, View childView, Object object) { 68 ViewGroup parent = getParentViewGroup(); 69 gridView.getViewSelectedOffsets(childView, mTmpOffsets); 70 mTmpRect.set(0, 0, childView.getWidth(), childView.getHeight()); 71 parent.offsetDescendantRectToMyCoords(childView, mTmpRect); 72 mCardLeft = mTmpRect.left - mTmpOffsets[0]; 73 mCardRight = mTmpRect.right - mTmpOffsets[0]; 74 select(object); 75 } 76 77} 78