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.fixedgridlayout;
18 
19 import android.content.Context;
20 import android.content.res.TypedArray;
21 import android.util.AttributeSet;
22 import android.util.SparseIntArray;
23 import android.view.Gravity;
24 import android.view.View;
25 import android.view.ViewGroup;
26 import android.view.ViewDebug;
27 
28 /**
29  * A layout that arranges its children in a grid.  The size of the
30  * cells is set by the {@link #setCellSize} method and the
31  * android:cell_width and android:cell_height attributes in XML.
32  * The number of rows and columns is determined at runtime.  Each
33  * cell contains exactly one view, and they flow in the natural
34  * child order (the order in which they were added, or the index
35  * in {@link #addViewAt}.  Views can not span multiple cells.
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 
FixedGridLayout(Context context, AttributeSet attrs)45     public FixedGridLayout(Context context, AttributeSet attrs) {
46         super(context, attrs);
47 
48         // Read the resource attributes.
49         TypedArray a = context.obtainStyledAttributes(
50                 attrs, R.styleable.FixedGridLayout);
51         mCellWidth = a.getDimensionPixelSize(
52                 R.styleable.FixedGridLayout_cellWidth, -1);
53         mCellHeight = a.getDimensionPixelSize(
54                 R.styleable.FixedGridLayout_cellHeight, -1);
55         a.recycle();
56     }
57 
setCellWidth(int px)58     public void setCellWidth(int px) {
59         mCellWidth = px;
60         requestLayout();
61     }
62 
setCellHeight(int px)63     public void setCellHeight(int px) {
64         mCellHeight = px;
65         requestLayout();
66     }
67 
68     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)69     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
70         int cellWidthSpec = MeasureSpec.makeMeasureSpec(mCellWidth,
71                 MeasureSpec.AT_MOST);
72         int cellHeightSpec = MeasureSpec.makeMeasureSpec(mCellHeight,
73                 MeasureSpec.AT_MOST);
74 
75         int count = getChildCount();
76         for (int index=0; index<count; index++) {
77             final View child = getChildAt(index);
78             child.measure(cellWidthSpec, cellHeightSpec);
79         }
80         // Use the size our parents gave us
81         setMeasuredDimension(resolveSize(mCellWidth*count, widthMeasureSpec),
82                 resolveSize(mCellHeight*count, heightMeasureSpec));
83     }
84 
85     @Override
onLayout(boolean changed, int l, int t, int r, int b)86     protected void onLayout(boolean changed, int l, int t, int r, int b) {
87         int cellWidth = mCellWidth;
88         int cellHeight = mCellHeight;
89         int columns = (r - l) / cellWidth;
90         if (columns < 0) {
91             columns = 1;
92         }
93         int x = 0;
94         int y = 0;
95         int i = 0;
96         int count = getChildCount();
97         for (int index=0; index<count; index++) {
98             final View child = getChildAt(index);
99 
100             int w = child.getMeasuredWidth();
101             int h = child.getMeasuredHeight();
102 
103             int left = x + ((cellWidth-w)/2);
104             int top = y + ((cellHeight-h)/2);
105 
106             child.layout(left, top, left+w, top+h);
107             if (i >= (columns-1)) {
108                 // advance to next row
109                 i = 0;
110                 x = 0;
111                 y += cellHeight;
112             } else {
113                 i++;
114                 x += cellWidth;
115             }
116         }
117     }
118 }
119 
120