19.5. Control of the Display function
A few lines of code are enough to use a Yocto-Display. Here is the skeleton of a Java code snippet
to use the Display function.
[
...
]
// Retrieving the object representing the module (connected here locally by USB)
YAPI
.
EnableUSBHost
(this);
YAPI
.
RegisterHub
(
"usb"
);
display
=
YDisplay
.
FindDisplay
(
"YD128X32-123456.display"
);
// Hot-plug is easy: just check that the device is online
if
(
display.
isOnline
())
{
//Use display.get_displayLayer()
...
}
[
...
]
Let us look at these lines in more details.
YAPI.EnableUSBHost
The
YAPI.EnableUSBHost
function initializes the API with the Context of the current application.
This function takes as argument an object of the
android.content.Context
class (or of a
subclass). If you intend to connect your application only to other machines through the network, this
function is facultative.
YAPI.RegisterHub
The
yAPI.RegisterHub
function initializes the Yoctopuce API and indicates where the modules
should be looked for. The parameter is the address of the virtual hub able to see the devices. If the
string "usb" is passed as parameter, the API works with modules locally connected to the machine. If
the initialization does not succeed, an exception is thrown.
YDisplay.FindDisplay
The
YDisplay.FindDisplay
function allows you to find a display from the serial number of the
module on which it resides and from its function name. You can use logical names as well, as long
as you have initialized them. Let us imagine a Yocto-Display module with serial number
YD128X32-123456
which you have named "
MyModule
", and for which you have given the
display
function the name "
MyFunction
". The following five calls are strictly equivalent, as long as
"
MyFunction
" is defined only once.
display
=
YDisplay
.
FindDisplay
(
"YD128X32-123456.display"
)
display
=
YDisplay
.
FindDisplay
(
"YD128X32-123456.MyFunction"
)
display
=
YDisplay
.
FindDisplay
(
"MyModule.display"
)
display
=
YDisplay
.
FindDisplay
(
"MyModule.MyFunction"
)
display
=
YDisplay
.
FindDisplay
(
"MyFunction"
)
YDisplay.FindDisplay
returns an object which you can then use at will to control the display.
isOnline
The
isOnline()
method of the object returned by
YDisplay.FindDisplay
allows you to
know if the corresponding module is present and in working order.
get_displayLayer
The
get_displayLayer()
method of the object returned by
YDisplay.FindDisplay
allows
you to retrieve the object corresponding to one of the screen layers. This object implements all the
graphical routines.
19. Using the Yocto-Display with Android
116
www.yoctopuce.com
Содержание Yocto-Display
Страница 1: ...Yocto Display User Manual...
Страница 2: ......
Страница 40: ...34 www yoctopuce com...
Страница 52: ...46 www yoctopuce com...
Страница 84: ...78 www yoctopuce com...
Страница 92: ...86 www yoctopuce com...
Страница 130: ...124 www yoctopuce com...
Страница 158: ...22 High level API Reference 152 www yoctopuce com On failure throws an exception or returns a negative error code...
Страница 422: ...416 www yoctopuce com...
Страница 424: ...24 Characteristics 418 www yoctopuce com...