Android™ Application Development - Bahar Ali Khan

Chapter 11: Advanced Android Development
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As the previous image is limited to black and white, you’ll need to create the control in order to see the
full effect.
1. Start by modifying the colors.xml resource fi le to include color values for the border gradient,
the glass compass shading, the sky, and the ground. Also update the colors used for the border
and the face markings.
#FFFF
#F000
#FFFF
#7AAA
#FF444444
#FF323232
#FF414141
#FFFFFFFF
#FFA52A2A
#FFFFC125
#FF5F9EA0
#FF00008B
2. The Paint and Shader objects used for the sky and ground in the artifi cial horizon are created
based on the size of the current View, so they’re not static like the Paint objects you created in
Chapter 4. Instead of creating Paint objects, construct the gradient arrays and colors they use.
int[] borderGradientColors;
float[] borderGradientPositions;
int[] glassGradientColors;
float[] glassGradientPositions;
int skyHorizonColorFrom;
int skyHorizonColorTo;
int groundHorizonColorFrom;
int groundHorizonColorTo;
3. Update the CompassView’s initCompassView method to initialize the variables created in Step
2 using the resources from Step 1. The existing method code can be left largely intact, with some
changes to the textPaint, circlePaint, and markerPaint variables, as highlighted below:
protected void initCompassView() {
setFocusable(true);
// Get external resources
Resources r = this.getResources();
circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
circlePaint.setColor(R.color.background_color);
circlePaint.setStrokeWidth(1);
circlePaint.setStyle(Paint.Style.STROKE);
northString = r.getString(R.string.cardinal_north);