1 /* 2 * Copyright (C) 2015 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 */ 14 package android.support.v17.leanback.widget; 15 16 import android.view.View; 17 18 import static android.support.v17.leanback.widget.BaseGridView.ITEM_ALIGN_OFFSET_PERCENT_DISABLED; 19 20 import android.support.v7.widget.RecyclerView; 21 22 /** 23 * Optional facet provided by {@link RecyclerView.Adapter} or {@link RecyclerView.ViewHolder} for 24 * use in {@link HorizontalGridView} and {@link VerticalGridView}. Apps using {@link Presenter} may 25 * set facet using {@link Presenter#setFacet(Class, Object)} or 26 * {@link Presenter.ViewHolder#setFacet(Class, Object)}. Facet on ViewHolder has a higher priority 27 * than Presenter or Adapter. 28 * <p> 29 * ItemAlignmentFacet contains single or multiple {@link ItemAlignmentDef}s. First 30 * {@link ItemAlignmentDef} describes the default alignment position for ViewHolder, it also 31 * overrides the default item alignment settings on {@link VerticalGridView} and 32 * {@link HorizontalGridView}. When there are multiple {@link ItemAlignmentDef}s, the extra 33 * {@link ItemAlignmentDef}s are used to calculate deltas from first alignment position. When a 34 * descendant view is focused within the ViewHolder, grid view will visit focused view and its 35 * ancestors till the root of ViewHolder to match extra {@link ItemAlignmentDef}s' 36 * {@link ItemAlignmentDef#getItemAlignmentViewId()}. Once a match found, the 37 * {@link ItemAlignmentDef} is used to adjust a scroll delta from default alignment position. 38 */ 39 public final class ItemAlignmentFacet { 40 41 /** 42 * Value indicates that percent is not used. 43 */ 44 public final static float ITEM_ALIGN_OFFSET_PERCENT_DISABLED = -1; 45 46 /** 47 * Definition of an alignment position under a view. 48 */ 49 public static class ItemAlignmentDef { 50 int mViewId = View.NO_ID; 51 int mFocusViewId = View.NO_ID; 52 int mOffset = 0; 53 float mOffsetPercent = 50f; 54 boolean mOffsetWithPadding = false; 55 private boolean mAlignToBaseline; 56 57 /** 58 * Sets number of pixels to offset. Can be negative for alignment from the high edge, or 59 * positive for alignment from the low edge. 60 */ setItemAlignmentOffset(int offset)61 public final void setItemAlignmentOffset(int offset) { 62 mOffset = offset; 63 } 64 65 /** 66 * Gets number of pixels to offset. Can be negative for alignment from the high edge, or 67 * positive for alignment from the low edge. 68 */ getItemAlignmentOffset()69 public final int getItemAlignmentOffset() { 70 return mOffset; 71 } 72 73 /** 74 * Sets whether to include left/top padding for positive item offset, include 75 * right/bottom padding for negative item offset. 76 */ setItemAlignmentOffsetWithPadding(boolean withPadding)77 public final void setItemAlignmentOffsetWithPadding(boolean withPadding) { 78 mOffsetWithPadding = withPadding; 79 } 80 81 /** 82 * When it is true: we include left/top padding for positive item offset, include 83 * right/bottom padding for negative item offset. 84 */ isItemAlignmentOffsetWithPadding()85 public final boolean isItemAlignmentOffsetWithPadding() { 86 return mOffsetWithPadding; 87 } 88 89 /** 90 * Sets the offset percent for item alignment in addition to offset. E.g., 40 91 * means 40% of the width from the low edge. Use {@link #ITEM_ALIGN_OFFSET_PERCENT_DISABLED} 92 * to disable. 93 */ setItemAlignmentOffsetPercent(float percent)94 public final void setItemAlignmentOffsetPercent(float percent) { 95 if ( (percent < 0 || percent > 100) && 96 percent != ITEM_ALIGN_OFFSET_PERCENT_DISABLED) { 97 throw new IllegalArgumentException(); 98 } 99 mOffsetPercent = percent; 100 } 101 102 /** 103 * Gets the offset percent for item alignment in addition to offset. E.g., 40 104 * means 40% of the width from the low edge. Use {@link #ITEM_ALIGN_OFFSET_PERCENT_DISABLED} 105 * to disable. 106 */ getItemAlignmentOffsetPercent()107 public final float getItemAlignmentOffsetPercent() { 108 return mOffsetPercent; 109 } 110 111 /** 112 * Sets Id of which child view to be aligned. View.NO_ID refers to root view and should 113 * be only used in first one. Extra ItemAlignmentDefs should provide view id to match 114 * currently focused view. 115 */ setItemAlignmentViewId(int viewId)116 public final void setItemAlignmentViewId(int viewId) { 117 mViewId = viewId; 118 } 119 120 /** 121 * Gets Id of which child view to be aligned. View.NO_ID refers to root view and should 122 * be only used in first one. Extra ItemAlignmentDefs should provide view id to match 123 * currently focused view. 124 */ getItemAlignmentViewId()125 public final int getItemAlignmentViewId() { 126 return mViewId; 127 } 128 129 /** 130 * Sets Id of which child view take focus for alignment. When not set, it will use 131 * use same id of {@link #getItemAlignmentViewId()} 132 */ setItemAlignmentFocusViewId(int viewId)133 public final void setItemAlignmentFocusViewId(int viewId) { 134 mFocusViewId = viewId; 135 } 136 137 /** 138 * Returns Id of which child view take focus for alignment. When not set, it will use 139 * use same id of {@link #getItemAlignmentViewId()} 140 */ getItemAlignmentFocusViewId()141 public final int getItemAlignmentFocusViewId() { 142 return mFocusViewId != View.NO_ID ? mFocusViewId : mViewId; 143 } 144 145 /** 146 * Align to baseline if {@link #getItemAlignmentViewId()} is a TextView and 147 * alignToBaseline is true. 148 * @param alignToBaseline Boolean indicating whether to align the text to baseline. 149 */ setAlignedToTextViewBaseline(boolean alignToBaseline)150 public final void setAlignedToTextViewBaseline(boolean alignToBaseline) { 151 this.mAlignToBaseline = alignToBaseline; 152 } 153 154 /** 155 * Returns true when TextView should be aligned to the baseline. 156 */ isAlignedToTextViewBaseLine()157 public boolean isAlignedToTextViewBaseLine() { 158 return mAlignToBaseline; 159 } 160 } 161 162 private ItemAlignmentDef[] mAlignmentDefs = new ItemAlignmentDef[]{new ItemAlignmentDef()}; 163 isMultiAlignment()164 public boolean isMultiAlignment() { 165 return mAlignmentDefs.length > 1; 166 } 167 168 /** 169 * Sets definitions of alignment positions. 170 */ setAlignmentDefs(ItemAlignmentDef[] defs)171 public void setAlignmentDefs(ItemAlignmentDef[] defs) { 172 if (defs == null || defs.length < 1) { 173 throw new IllegalArgumentException(); 174 } 175 mAlignmentDefs = defs; 176 } 177 178 /** 179 * Returns read only definitions of alignment positions. 180 */ getAlignmentDefs()181 public ItemAlignmentDef[] getAlignmentDefs() { 182 return mAlignmentDefs; 183 } 184 185 } 186