Java Reference
In-Depth Information
Getting ready
In
Chapter 5
,
JavaFX Media
, we learned how to use the Image API to download images
automatically. However, the API offers little control over the download process. In this recipe,
we are going to use
HttpRequest,
which provides granular control over the content of the
image downloaded. For some portions of the code, you will need to be familiar with the use of
JavaFX data binding and triggers (see
Chapter 1
,
Getting Started with JavaFX
for details). For
a background on how to display images in JavaFX, review the recipe
Loading and displaying
images with ImageView
from
Chapter 5
,
JavaFX Media
.
To illustrate the use of
HttpRequest
, we are going to build a Google Map application.
The application uses the Google Static Map API to download static map images based on
a provided address. The example requires a Google API Key to run. You can get your own
Google API Key at
http://code.google.com/apis/maps/signup.html
.
How to do it...
The abbreviated version of the code provided next shows the essential portions needed to
show how to pull down an image from Google's map server. The code listing intentionally
leaves out portion of the code used to assemble the GUI components (topics on GUI controls
are covered in
Chapter 4
,
Components and Skinning
). Refer to
ch06/source-code/src/
http/HttpRequestGoogleMap.fx
for a complete listing of the code.
var w = 640;
var h = 480;
var bytesToRead:Long;
var currentBytesRead:Long;
var imgW = w * 0.8;
var imgH = h * 0.7;
var
converter
= URLConverter{}
var loc =
converter
.encodeString("Atlanta, GA");
var zoom:Number = 15;
var mapType="roadmap";
def apiKey="PLACE_YOUR_GOOGLE_API_KEY_HERE";
var
gmapUrl
=
bind
"http://maps.google.com/maps/api/staticmap?"
"center={loc}"
"&zoom={zoom as Integer}"
"&size={imgW as Integer}x{imgH as Integer}"
"&maptype={mapType}"
"&format=png32"
"&markers=color:blue|{loc}"
"&sensor=false"
"&key={apiKey}"
on replace
{
