1 /*
2  * Copyright (C) 2009 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 
17 package com.example.android.apis.animation;
18 
19 import android.content.Context;
20 import android.content.res.TypedArray;
21 import android.util.AttributeSet;
22 import android.view.View;
23 import android.view.ViewGroup;
24 
25 /**
26  * A layout that arranges its children in a grid.  The size of the
27  * cells is set by the {@link #setCellSize} method and the
28  * android:cell_width and android:cell_height attributes in XML.
29  * The number of rows and columns is determined at runtime.  Each
30  * cell contains exactly one view, and they flow in the natural
31  * child order (the order in which they were added, or the index
32  * in {@link #addViewAt}.  Views can not span multiple cells.
33  *
34  * <p>This class was copied from the FixedGridLayout Api demo; see that demo for
35  * more information on using the layout.</p>
36  */
37 public class FixedGridLayout extends ViewGroup {
38     int mCellWidth;
39     int mCellHeight;
40 
FixedGridLayout(Context context)41     public FixedGridLayout(Context context) {
42         super(context);
43     }
44 
setCellWidth(int px)45     public void setCellWidth(int px) {
46         mCellWidth = px;
47         requestLayout();
48     }
49 
setCellHeight(int px)50     public void setCellHeight(int px) {
51         mCellHeight = px;
52         requestLayout();
53     }
54 
55     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)56     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
57         int cellWidthSpec = MeasureSpec.makeMeasureSpec(mCellWidth,
58                 MeasureSpec.AT_MOST);
59         int cellHeightSpec = MeasureSpec.makeMeasureSpec(mCellHeight,
60                 MeasureSpec.AT_MOST);
61 
62         int count = getChildCount();
63         for (int index=0; index<count; index++) {
64             final View child = getChildAt(index);
65             child.measure(cellWidthSpec, cellHeightSpec);
66         }
67         // Use the size our parents gave us, but default to a minimum size to avoid
68         // clipping transitioning children
69         int minCount =  count > 3 ? count : 3;
70         setMeasuredDimension(resolveSize(mCellWidth * minCount, widthMeasureSpec),
71                 resolveSize(mCellHeight * minCount, heightMeasureSpec));
72     }
73 
74     @Override
onLayout(boolean changed, int l, int t, int r, int b)75     protected void onLayout(boolean changed, int l, int t, int r, int b) {
76         int cellWidth = mCellWidth;
77         int cellHeight = mCellHeight;
78         int columns = (r - l) / cellWidth;
79         if (columns < 0) {
80             columns = 1;
81         }
82         int x = 0;
83         int y = 0;
84         int i = 0;
85         int count = getChildCount();
86         for (int index=0; index<count; index++) {
87             final View child = getChildAt(index);
88 
89             int w = child.getMeasuredWidth();
90             int h = child.getMeasuredHeight();
91 
92             int left = x + ((cellWidth-w)/2);
93             int top = y + ((cellHeight-h)/2);
94 
95             child.layout(left, top, left+w, top+h);
96             if (i >= (columns-1)) {
97                 // advance to next row
98                 i = 0;
99                 x = 0;
100                 y += cellHeight;
101             } else {
102                 i++;
103                 x += cellWidth;
104             }
105         }
106     }
107 }
108 
109