Android™ Application Development - Bahar Ali Khan

Paint glassPaint = new Paint();
glassPaint.setShader(glassShader);
Chapter 11: Advanced Android Development
canvas.drawOval(innerBoundingBox, glassPaint);
glassGradientColors,
glassGradientPositions,
TileMode.CLAMP);
18. All that’s left is to draw two more circles as clean borders for the inner and outer face boundaries.
Then restore the canvas to upright, and fi nish the onDraw method.
// Draw the outer ring
canvas.drawOval(boundingBox, circlePaint);
}
// Draw the inner ring
circlePaint.setStrokeWidth(2);
canvas.drawOval(innerBoundingBox, circlePaint);
canvas.restore();
Bringing Map Overlays to Life
In Chapter 7, you learned how to use Overlays to add annotation layers to MapViews. The Canvas used
for annotating MapView Overlays is the same class as the one used to draw new View controls. As a
result, all of the advanced features described so far in this section can be used to enhance map Overlays.
That means you can use any of the draw methods, transparency, Shaders, Color Masks, and Filter
Effects to create rich Overlays using the Android graphics framework.
Interacting with Overlays
Touch-screen interaction in MapViews is handled individually by each of its Overlays. To handle map
taps within an Overlay, override the onTap event.
The following code snippet shows an onTap implementation that receives the map coordinates of the
tap and the MapView on which the tap occurred:
@Override
public boolean onTap(GeoPoint point, MapView map) {
// Get the projection to convert to and from screen coordinates
Projection projection = map.getProjection();
}
// Return true if we handled this onTap()
return [ … hit test passed … ];
The MapView can be used to obtain the Projection of the map when it was tapped. Used in conjunction
with the GeoPoint parameter, you can determine the position on screen of the real-world longitude
and latitude pressed.
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