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
17package com.example.android.fixedgridlayout;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.util.AttributeSet;
22import android.util.SparseIntArray;
23import android.view.Gravity;
24import android.view.View;
25import android.view.ViewGroup;
26import 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 */
37public class FixedGridLayout extends ViewGroup {
38    int mCellWidth;
39    int mCellHeight;
40
41    public FixedGridLayout(Context context) {
42        super(context);
43    }
44
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
58    public void setCellWidth(int px) {
59        mCellWidth = px;
60        requestLayout();
61    }
62
63    public void setCellHeight(int px) {
64        mCellHeight = px;
65        requestLayout();
66    }
67
68    @Override
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
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