Study the small print of the consumer’s welcome display screen to create a extra partaking and customized expertise
Understanding the internals of the Leanback API could be difficult at occasions, however that is what we, as builders, must do to verify we are able to create apps that look and performance correctly. genuine with its customers. On this submit, we are going to dive into HeadersSupportFragment
is part of BrowseSupportFragment
and is sort of all the time the primary piece of content material a consumer sees in an Android TV app. We are going to study its creation course of, the way it works and the way we are able to customise it.
As acknowledged within the introduction, the HeadersSupportFragment
Is part of BrowseSupportFragment.
The BrowseSupportFragment
is often the primary display screen customers see when opening the Android TV app, and it is the place customers can browse and uncover content material.
HeadersSupportFragment creation and configuration
The BrowseSupportFragment
there’s a operate known as onCreateHeadersSupportFragment()
liable for returning an occasion of HeadersSupportFragment
used inside it. It is a public operate, so you possibly can override it if you wish to present your personal customized implementation HeadersSupportFragment
.
public HeadersSupportFragment onCreateHeadersSupportFragment() {
return new HeadersSupportFragment();
}
Then nonetheless in BrowseSupportFragment.onCreateView()
the HeadersSupportFragment
added to its container by a FragmentTransaction
carried out by BrowseSupportFragment
. Then the next steps happen:
- Replace
HeadersSupportFragment
visibility based mostly on standing handed toBrowseSupportFragment.setHeaderState(state)
. Out there states are:
/** The headers fragment is enabled and proven by default. */
public static closing int HEADERS_ENABLED = 1;
/** The headers fragment is enabled and hidden by default. */
public static closing int HEADERS_HIDDEN = 2;
/** The headers fragment is disabled and can by no means be proven. */
public static closing int HEADERS_DISABLED = 3;
- name
HeadersSupportFragment.setPresenterSelector()
overcomePresenterSelector
supplied forBrowseSupportFragment.setHeaderPresenterSelector()
. ThisPresenterSelector
ought to help at the least three forms of objects. That’s,DividerRow
,SectionRow
AndRow
.
Observe: the HeadersSupportFragment
There are already out-of-the-box implementations for these Row
varieties, however we are able to present customized implementations. As one HeaderSupportFragment
is a subclass of BaseRowSupportFragmeent
customise its rows, it is only a matter of getting a customized Presenter
for its objects.
- The
HeadersSupportFragment
has its adapter,OnHeaderViewSelectedListener
AndOnHeaderClickedListener
set. The adapter is liable for delivering the objects. The default implementation for itOnHeaderViewSelectedLister
change or choose the content material ofBrowseSupportFrament
. ForOnHeaderClickedListener
Its default setting is hiddenHeaderSupportFragment
when an merchandise is clicked. - Background coloration of
HeadersSupportFragment
set utilizing the colour supplied forBrowseSupportFragment.setBrandColor()
. For instance:
override enjoyable onCreateHeadersSupportFragment(): HeadersSupportFragment {
// This can be performed on the onViewCreated()
brandColor = Colour.RED
return tremendous.onCreateHeadersSupportFragment()
}
- At this level, the
BrowseSupportFragment.onViewCreated()
finish andBrowseSupportFragment.onStart()
might be known as. InsideonStart()
the affiliation ofHeadersSupportFragment
might be set based mostly on the Leanback theme attribute namedbrowseRowsMarginTop
. This attribute, because the title implies, can also be utilized byBrowseSupportFragment
to set the highest margin of the primary row. - If you wish to change
HeadersSupportFragment
align the objects, you want to take action after the decision totremendous.onCreate()
override enjoyable onStart() {
tremendous.onStart()
headersSupportFragment.setAlignment(400)
}
Observe: The concept of eachHeadersSupportFragment
And BrowseSupportFragment
use the identical worth from browseRowsMarginTop
setting a high margin helps them higher align the chosen row on the header with the chosen row on BrowseSupportFragment
when BrowseSupportFragment
used just for show ListRows
. If BrowseSupportFragment
exhibiting a PageRow
this affiliation will not be vital as a result of PageRow
content material will fill the complete paragraph.
We are going to embody PageRows
and particulars of BrowseSupportFragment
on one other submit. Remember to observe me to be notified when it is launched!
- You possibly can allow or disable the titles of a
BrowseSupportFragment
by organising a nameBrowseSupportFragment.setHeaderState(state)
and go the specified state. - Change
HeadersSupportFragment
background coloration by callingHeadersSupportFragment.setBrandColor(coloration)
. - Change or provide new varieties
Presenter
for youHeadersSupportFragment
. - Change
OnHeaderViewSelectedListener
AndOnHeaderClickListener
your deploymentHeadersSupportFragment
.
As we noticed earlier, the HeadersSupportFragment
ought to help three totally different merchandise varieties: DividerRow
, SectionRow
And Row
. Let’s have a look at how these things are displayed with their defaults Presenter
deployment.
IconSectionRow and IconSectionPresenter
To point out how we are able to customise the objects of a HeadersSupportFragment
we are going to create a IconSectionPresenter
which is able to make a SectionRow
with a picture to the left of its textual content.
Let’s begin by making a subclass of SectionRow
accommodates the id of a drawable to make use of on the row.
class IconSectionRow(
@DrawableRes val icon: Int,
headerItem: HeaderItem
) : SectionRow(headerItem)
Then we have to create a Presenter
able to performing the creation and binding of a IconSectionRow
. We are going to do it by increasing RowHeaderPresenter
and simply add a couple of traces.
And that is R.format.icon_section_row
.
Observe: When making a format for non-focusable rows, equivalent to dividers and sections, disable deal with its mother or father view. In any other case, they are going to be capable to obtain focus and this will generally result in ClassCastException
relying in your merchandise kind and ViewHolder
used for it as HeadersSupportFragment
attempt to transmit chosen objects ViewHolders
ARRIVE RowHeaderPresenter.ViewHolder
.
DividerRow and DividerSpacePresenter
Much like how we create customized Presenter
giveSectionRow
we are going to make one for DividerRow
. We’ll construct a presenter that shows the divider as an area as an alternative of 1dp
line. On this case we solely want a customized presenter, as a result of the merchandise, DividerRow
doesn’t must include any extra data (just like the phrase image IconSectionRow
).
Add customized presenters
Lastly, we’ve got so as to add each newly created presenters HeadersSupportFragment
presenter selector. Ensure you are doing this solely after the incoming name BrowseSupportFragment.onCreateView()
ending, like HeadersSupportFragment
solely initialized inside it.
your inside BrowseSupportFragment
or in your customized implementation HeadersSupportFragment
please do the next:
Theme managed properties
Some phrase attributes HeadersSupportFragment
powered by your app theme. When creating themes for Android TV apps, it is best to broaden from Theme.Leanback
. This base theme has all of the properties that Leanback parts use to set measurement, margin, padding, coloration, and so forth. Beneath is a listing of properties utilized by HeadersSupportFragment
.
-
lb_browse_headers_width
: Width ofHeadersSupportFragment
. -
lb_browse_headers_paddding_end
:HeadersSupportFragment
finish buffer. -
lb_browse_headers_z
: Altitude ofHeadersSupportFragment
authentic view. -
lb_browse_header_fading_length
: Pale edge width. The fade edge covers the top of the title textual content when the textual content is just too lengthy. -
lb_headers_right_fading
: The drawable background utilized by the fade edge. -
headersVerticalGridStyle
: Fashion forVerticalGridView
LaterHeadersSupportfragment
. The default theme is configured as proven under:
-
lb_section_header
&lb_header
: Default format file forSectionRow
AndRow
views, respectively.
Observe: above pattern appnone of those theme properties are modified.
Thanks for studying this text! Ensure to examine the pattern app specifically created for this text. Have a look at official doc ABOVE HeadersSupportFragment
.
Additionally, take a look at this record that I created together with my Android TV Leanback collection articles:
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📺 Backrest Information for Android TV
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