61 lines
2.3 KiB
Markdown
61 lines
2.3 KiB
Markdown
|
```eval_rst
|
||
|
|
.. include:: /header.rst
|
||
|
|
:github_url: |github_link_base|/others/gridnav.md
|
||
|
|
```
|
||
|
|
# Grid navigation
|
||
|
|
|
||
|
|
Grid navigation (gridnav for short) is a feature that changes the currently focused child object as arrow keys are pressed.
|
||
|
|
|
||
|
|
If the children are arranged into a grid-like layout then the up, down, left and right arrows move focus to the nearest sibling
|
||
|
|
in the respective direction.
|
||
|
|
|
||
|
|
It doesn't matter how the children are positioned, as only the current x and y coordinates are considered.
|
||
|
|
This means that gridnav works with manually positioned children, as well as [Flex](/layouts/flex) and [Grid](/layouts/grid) layouts.
|
||
|
|
|
||
|
|
Gridnav also works if the children are arranged into a single row or column.
|
||
|
|
That makes it useful, for example, to simplify navigation on a [List widget](/widgets/extra/list).
|
||
|
|
|
||
|
|
Gridnav assumes that the object to which gridnav is added is part of a [group](/overview/indev.html#groups).
|
||
|
|
This way, if the object with gridnav is focused, the arrow key presses are automatically forwarded to the object
|
||
|
|
so that gridnav can process the arrow keys.
|
||
|
|
|
||
|
|
To move the focus to the next widget of the group use `LV_KEY_NEXT/PREV` or `lv_group_focus_next/prev()` or the `TAB` key on keyboard as usual.
|
||
|
|
|
||
|
|
If the container is scrollable and the focused child is out of the view, gridnav will automatically scroll the child into view.
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
To add the gridnav feature to an object use `lv_gridnav_add(cont, flags)`.
|
||
|
|
|
||
|
|
`flags` control the behavior of gridnav:
|
||
|
|
- `LV_GRIDNAV_CTRL_NONE` Default settings
|
||
|
|
- `LV_GRIDNAV_CTRL_ROLLOVER` If there is no next/previous object in a direction,
|
||
|
|
the focus goes to the object in the next/previous row (on left/right keys) or first/last row (on up/down keys
|
||
|
|
- `LV_GRIDNAV_CTRL_SCROLL_FIRST` If an arrow is pressed and the focused object can be scrolled in that direction
|
||
|
|
then it will be scrolled instead of going to the next/previous object. If there is no more room for scrolling the next/previous object will be focused normally
|
||
|
|
|
||
|
|
`lv_gridnav_remove(cont)` Removes gridnav from an object.
|
||
|
|
|
||
|
|
## Focusable objects
|
||
|
|
|
||
|
|
An object needs to be clickable or click focusable (`LV_OBJ_FLAG_CLICKABLE` or `LV_OBJ_FLAG_CLICK_FOCUSABLE`)
|
||
|
|
and not hidden (`LV_OBJ_FLAG_HIDDEN`) to be focusable by gridnav.
|
||
|
|
|
||
|
|
|
||
|
|
## Example
|
||
|
|
|
||
|
|
```eval_rst
|
||
|
|
|
||
|
|
.. include:: ../../examples/others/gridnav/index.rst
|
||
|
|
|
||
|
|
```
|
||
|
|
## API
|
||
|
|
|
||
|
|
|
||
|
|
```eval_rst
|
||
|
|
|
||
|
|
.. doxygenfile:: lv_gridnav.h
|
||
|
|
:project: lvgl
|
||
|
|
|
||
|
|
```
|