ItemAlignment.java revision c26ebee190513b93c6f30620dac3bfc9038cb621 
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 */
14
15package android.support.v17.leanback.widget;
16
17import static android.support.v7.widget.RecyclerView.HORIZONTAL;
18import static android.support.v7.widget.RecyclerView.VERTICAL;
19import static android.support.v17.leanback.widget.BaseGridView.ITEM_ALIGN_OFFSET_PERCENT_DISABLED;
20
21import android.graphics.Rect;
22import android.support.v17.leanback.widget.GridLayoutManager.LayoutParams;
23import android.view.View;
24import android.view.ViewGroup;
25
26/**
27 * Defines alignment position on two directions of an item view. Typically item
28 * view alignment is at the center of the view. The class allows defining
29 * alignment at left/right or fixed offset/percentage position; it also allows
30 * using descendant view by id match.
31 */
32class ItemAlignment {
33
34    final static class Axis {
35        private int mOrientation;
36        private int mOffset = 0;
37        private float mOffsetPercent = 50;
38        private int mViewId = 0;
39        private Rect mRect = new Rect();
40
41        Axis(int orientation) {
42            mOrientation = orientation;
43        }
44
45        public void setItemAlignmentOffset(int offset) {
46            mOffset = offset;
47        }
48
49        public int getItemAlignmentOffset() {
50            return mOffset;
51        }
52
53        public void setItemAlignmentOffsetPercent(float percent) {
54            if ( (percent < 0 || percent > 100) &&
55                    percent != ITEM_ALIGN_OFFSET_PERCENT_DISABLED) {
56                throw new IllegalArgumentException();
57            }
58            mOffsetPercent = percent;
59        }
60
61        public float getItemAlignmentOffsetPercent() {
62            return mOffsetPercent;
63        }
64
65        public void setItemAlignmentViewId(int viewId) {
66            mViewId = viewId;
67        }
68
69        public int getItemAlignmentViewId() {
70            return mViewId;
71        }
72
73        public int getAlignmentPosition(View itemView) {
74
75            LayoutParams p = (LayoutParams) itemView.getLayoutParams();
76            View view = itemView;
77            if (mViewId != 0) {
78                view = itemView.findViewById(mViewId);
79                if (view == null) {
80                    view = itemView;
81                }
82            }
83            int alignPos;
84            if (mOrientation == HORIZONTAL) {
85                if (mOffset >= 0) {
86                    alignPos = mOffset;
87                } else {
88                    alignPos = p.getOpticalWidth(itemView) + mOffset;
89                }
90                if (mOffsetPercent != ITEM_ALIGN_OFFSET_PERCENT_DISABLED) {
91                    alignPos += (p.getOpticalWidth(itemView) * mOffsetPercent) / 100;
92                }
93                if (itemView != view) {
94                    mRect.left = alignPos;
95                    ((ViewGroup) itemView).offsetDescendantRectToMyCoords(view, mRect);
96                    alignPos = mRect.left;
97                }
98            } else {
99                if (mOffset >= 0) {
100                    alignPos = mOffset;
101                } else {
102                    alignPos = p.getOpticalHeight(itemView) + mOffset;
103                }
104                if (mOffsetPercent != ITEM_ALIGN_OFFSET_PERCENT_DISABLED) {
105                    alignPos += (p.getOpticalHeight(itemView) * mOffsetPercent) / 100;
106                }
107                if (itemView != view) {
108                    mRect.top = alignPos;
109                    ((ViewGroup) itemView).offsetDescendantRectToMyCoords(view, mRect);
110                    alignPos = mRect.top;
111                }
112            }
113            return alignPos;
114        }
115    }
116
117    private int mOrientation = HORIZONTAL;
118
119    final public Axis vertical = new Axis(VERTICAL);
120
121    final public Axis horizontal = new Axis(HORIZONTAL);
122
123    private Axis mMainAxis = horizontal;
124
125    private Axis mSecondAxis = vertical;
126
127    final public Axis mainAxis() {
128        return mMainAxis;
129    }
130
131    final public Axis secondAxis() {
132        return mSecondAxis;
133    }
134
135    final public void setOrientation(int orientation) {
136        mOrientation = orientation;
137        if (mOrientation == HORIZONTAL) {
138            mMainAxis = horizontal;
139            mSecondAxis = vertical;
140        } else {
141            mMainAxis = vertical;
142            mSecondAxis = horizontal;
143        }
144    }
145
146    final public int getOrientation() {
147        return mOrientation;
148    }
149
150
151}
152