Android Development

Android 2.1 SDK is out. The API level changed to 7 but its mainly a minor update.
New stuff: the animated background you already know from Nexus One and a new SignalStrength class which provides information about the device’s current network signal.

Anything else are mainly new methods on already existing classes.

The update is available as a download or as an update in your SDK Manager.

This how to will show you how you can create a simple 2D Map with Cells to place stuff on it. Just like the old school SimCity.

The first thing you need is an Activity with a SurfaceView and a Thread to trigger the drawing. Who doesn’t know these fundamentals, please read my series on 2d graphics first.

Lets start with the smallest unit for our map: the Cell.
Each Cell will have a background color and a unique ID.

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package com.droidnova.android.games;
 
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
 
/**
 * A part of the map.
 */
public class Cell {
    public int _id = 0;
    public int _backgroundColor = Color.GREEN;
 
    /**
     * Konstruktor.
     * @param id
     */
    public Cell(int id) {
        _id = id;
    }
 
    /**
     * Draw the cell
     *  
     * @param canvas Canvas to draw on.
     * @param paint Color of the "pencil".
     * @param x X coordinate.
     * @param y Y coordinate.
     */
    public void draw(Canvas canvas, Paint paint, int x, int y) {
        paint.setColor(_backgroundColor);
        canvas.drawRect(x, y, x + CellMap._cellSize, y + CellMap._cellSize, paint);
 
        paint.setColor(Color.BLACK);
        canvas.drawText("" + _id, x + 1, y + 10, paint);
    }
}

On line 32 you see, how we draw the cell. The variable _cellSize is a static variable from CellMap, which will be introduced later. Everything else should be already known.
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