Android example source code file (Maze.java)

This example Android source code file (Maze.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, bitmap, drawing, exit_tile, graphics, inputstream, io, ioexception, max_levels, maze, maze_cols, maze_rows, paint, path_tile, rect, string, tile_size, ui, void_color, void_tile

The Maze.java Android example source code

/*
 * Copyright (C) 2008 Jason Tomlinson.
 *
 * 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.amazed;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.Log;

/**
 * Maze drawn on screen, each new level is loaded once the previous level has
 * been completed.
 */
public class Maze {
	
    // maze tile size and dimension
    private final static int TILE_SIZE = 16;
    private final static int MAZE_COLS = 20;
    private final static int MAZE_ROWS = 26;

    // tile types
    public final static int PATH_TILE = 0;
    public final static int VOID_TILE = 1;
    public final static int EXIT_TILE = 2;

    // tile colors
    private final static int VOID_COLOR = Color.BLACK;

    // maze level data
    private static int[] mMazeData;

    // number of level
    public final static int MAX_LEVELS = 10;

    // current tile attributes
    private Rect mRect = new Rect();
    private int mRow;
    private int mCol;
    private int mX;
    private int mY;

    // tile bitmaps
    private Bitmap mImgPath;
    private Bitmap mImgExit;

    /**
     * Maze constructor.
     * 
     * @param context
     *            Application context used to load images.
     */
    Maze(Activity activity) {

        // load bitmaps.
        mImgPath = BitmapFactory.decodeResource(activity.getApplicationContext().getResources(),
                R.drawable.path);
        mImgExit = BitmapFactory.decodeResource(activity.getApplicationContext().getResources(),
                R.drawable.exit);
    }

    /**
     * Load specified maze level.
     * 
     * @param activity
     *           Activity controlled the maze, we use this load the level data
     * @param newLevel
     *            Maze level to be loaded.
     */
    void load(Activity activity, int newLevel) {
        // maze data is stored in the assets folder as level1.txt, level2.txt
        // etc....
        String mLevel = "level" + newLevel + ".txt";

        InputStream is = null;

        try {
            // construct our maze data array.
            mMazeData = new int[MAZE_ROWS * MAZE_COLS];
            // attempt to load maze data.
            is = activity.getAssets().open(mLevel);

            // we need to loop through the input stream and load each tile for
            // the current maze.
            for (int i = 0; i < mMazeData.length; i++) {
                // data is stored in unicode so we need to convert it.
                mMazeData[i] = Character.getNumericValue(is.read());

                // skip the "," and white space in our human readable file.
                is.read();
                is.read();
            }
        } catch (Exception e) {
            Log.i("Maze", "load exception: " + e);
        } finally {
            closeStream(is);
        }

    }

    /**
     * Draw the maze.
     * 
     * @param canvas
     *            Canvas object to draw too.
     * @param paint
     *            Paint object used to draw with.
     */
    public void draw(Canvas canvas, Paint paint) {
        // loop through our maze and draw each tile individually.
        for (int i = 0; i < mMazeData.length; i++) {
            // calculate the row and column of the current tile.
            mRow = i / MAZE_COLS;
            mCol = i % MAZE_COLS;

            // convert the row and column into actual x,y co-ordinates so we can
            // draw it on screen.
            mX = mCol * TILE_SIZE;
            mY = mRow * TILE_SIZE;

            // draw the actual tile based on type.
            if (mMazeData[i] == PATH_TILE)
                canvas.drawBitmap(mImgPath, mX, mY, paint);
            else if (mMazeData[i] == EXIT_TILE)
                canvas.drawBitmap(mImgExit, mX, mY, paint);
            else if (mMazeData[i] == VOID_TILE) {
                // since our "void" tile is purely black lets draw a rectangle
                // instead of using an image.

                // tile attributes we are going to paint.
                mRect.left = mX;
                mRect.top = mY;
                mRect.right = mX + TILE_SIZE;
                mRect.bottom = mY + TILE_SIZE;

                paint.setColor(VOID_COLOR);
                canvas.drawRect(mRect, paint);
            }
        }

    }

    /**
     * Determine which cell the marble currently occupies.
     * 
     * @param x
     *            Current x co-ordinate.
     * @param y
     *            Current y co-ordinate.
     * @return The actual cell occupied by the marble.
     */
    public int getCellType(int x, int y) {
        // convert the x,y co-ordinate into row and col values.
        int mCellCol = x / TILE_SIZE;
        int mCellRow = y / TILE_SIZE;

        // location is the row,col coordinate converted so we know where in the
        // maze array to look.
        int mLocation = 0;

        // if we are beyond the 1st row need to multiple by the number of
        // columns.
        if (mCellRow > 0)
            mLocation = mCellRow * MAZE_COLS;

        // add the column location.
        mLocation += mCellCol;

        return mMazeData[mLocation];
    }

    /**
     * Closes the specified stream.
     * 
     * @param stream
     *            The stream to close.
     */
    private static void closeStream(Closeable stream) {
        if (stream != null) {
            try {
                stream.close();
            } catch (IOException e) {
                // Ignore
            }
        }
    }
}