Java Reference
In-Depth Information
F
Display and add interaction
—once the images are loaded in the
images[]
sequence,
we can now create the
ImageView
object assigned to variable
imgView
that will
display the images.
The
ImageView
instance requests focus using the
imgView.
requestFocus()
function call. This causes the
imgView
component to receive keyboard events.
A keyboard input event-handler function is attached to
imgView
to handle keyboard key presses. The code loops through the
sequence of
images
to look for an
Image
instance whose
url
property contains the value of the key pressed, as shown in the
following snippet:
for(i in images){
if(i.url.contains("{e.text}.png")) {
img = i;
break;
}
}
When the image is found, the value is assigned to
imgView.image
for display.
There's more...
A general approach to loading multiple images automatically is to use a predictable sequence
to name your image files. For instance, for this recipe, we can use a numeric sequence of
integers as a part of the file name instead of just the alphabet sequence of letters. So, the
image for letter A is named
letter_0.png
, the image for letter B is named
letter_1.png
,
and so forth, with the image for letter Z named
letter_25.png
. By doing this, our code gets
even smaller, where we no longer need the sequence
alphabet[]
to store the image names.
We can load the images as follows:
for (id in [0..25]){
insert Image {
url: "{__DIR__}images/letter_{id}.png"
backgroundLoading: false
width:imgW height:imgH
} into images;
}
See also
F
Chapter 1
—
Creating
and
using
JavaFX
sequences
F
Chapter 5
—
Loading
and
displaying
images
with
ImageView
