Add the FixedGridLayout sample code.

This time with an Android.mk

P.S. Hi from Google I/O!

samples/FixedGridLayout/src/com/example/android/fixedgridlayout/FixedGridLayout.java

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+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.fixedgridlayout;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.util.SparseIntArray;
+import android.view.Gravity;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewDebug;
+
+/**
+ * A layout that arranges its children in a grid.  The size of the
+ * cells is set by the {@link #setCellSize} method and the
+ * android:cell_width and android:cell_height attributes in XML.
+ * The number of rows and columns is determined at runtime.  Each
+ * cell contains exactly one view, and they flow in the natural
+ * child order (the order in which they were added, or the index
+ * in {@link #addViewAt}.  Views can not span multiple cells.
+ */
+public class FixedGridLayout extends ViewGroup {
+    int mCellWidth;
+    int mCellHeight;
+
+    public FixedGridLayout(Context context) {
+        super(context);
+    }
+
+    public FixedGridLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        // Read the resource attributes.
+        TypedArray a = context.obtainStyledAttributes(
+                attrs, R.styleable.FixedGridLayout);
+        mCellWidth = a.getDimensionPixelSize(
+                R.styleable.FixedGridLayout_cellWidth, -1);
+        mCellHeight = a.getDimensionPixelSize(
+                R.styleable.FixedGridLayout_cellHeight, -1);
+        a.recycle();
+    }
+
+    public void setCellWidth(int px) {
+        mCellWidth = px;
+        requestLayout();
+    }
+
+    public void setCellHeight(int px) {
+        mCellHeight = px;
+        requestLayout();
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        int cellWidthSpec = MeasureSpec.makeMeasureSpec(mCellWidth,
+                MeasureSpec.AT_MOST);
+        int cellHeightSpec = MeasureSpec.makeMeasureSpec(mCellHeight,
+                MeasureSpec.AT_MOST);
+
+        int count = getChildCount();
+        for (int index=0; index<count; index++) {
+            final View child = getChildAt(index);
+            child.measure(cellWidthSpec, cellHeightSpec);
+        }
+        // Use the size our parents gave us
+        setMeasuredDimension(resolveSize(mCellWidth*count, widthMeasureSpec),
+                resolveSize(mCellHeight*count, heightMeasureSpec));
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        int cellWidth = mCellWidth;
+        int cellHeight = mCellHeight;
+        int columns = (r - l) / cellWidth;
+        if (columns < 0) {
+            columns = 1;
+        }
+        int x = 0;
+        int y = 0;
+        int i = 0;
+        int count = getChildCount();
+        for (int index=0; index<count; index++) {
+            final View child = getChildAt(index);
+
+            int w = child.getMeasuredWidth();
+            int h = child.getMeasuredHeight();
+
+            int left = x + ((cellWidth-w)/2);
+            int top = y + ((cellHeight-h)/2);
+
+            child.layout(left, top, left+w, top+h);
+            if (i >= (columns-1)) {
+                // advance to next row
+                i = 0;
+                x = 0;
+                y += cellHeight;
+            } else {
+                i++;
+                x += cellWidth;
+            }
+        }
+    }
+}
+

samples/FixedGridLayout/src/com/example/android/fixedgridlayout/FixedGridLayoutTest.java

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+package com.example.android.fixedgridlayout;
+
+import android.app.Activity;
+import android.os.Bundle;
+
+public class FixedGridLayoutTest extends Activity
+{
+    /** Called when the activity is first created. */
+    @Override
+    public void onCreate(Bundle savedInstanceState)
+    {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.main);
+
+        FixedGridLayout grid = (FixedGridLayout)findViewById(R.id.grid);
+        grid.setCellWidth(80);
+        grid.setCellHeight(80);
+    }
+}