I am building an Android TV app with the following layout:
Both lists on the left and on the right are RecyclerViews with vertical LinearLayoutManagers, Header view is static. Navigation with D-PAD works fine within one list, but when switching from one list to another there are issues. Focus moves from, say list1's item 5 to list2' item 5. When list 2 is short has less than 5 items, it just loses focus.
I want the last focused item index saved and when the user navigates list1-list2-list1 the item with that index to gain focus again and also prevent the views from losing focus. Is there any good solution to this?
Required behaviour: user navigates to the top of the list and presses "UP" - focus stays where it was, nothing happens. user navigates to the bottom of the list and presses "DOWN" - focus stays where it was, nothing happens. user navigates from list1 to list2 - the item, that previously had focus in list2, gains focus or item0 gains focus if none was focused previously.
main layout:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ImageView
android:id="@+id/iv_background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="false"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="27dp"
android:layout_marginLeft="48dp"
android:layout_marginRight="48dp"
android:layout_marginTop="27dp"
android:orientation="horizontal"
>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:focusable="false"
android:orientation="horizontal"
>
<ImageView
android:id="@+id/iv_poster"
android:layout_width="@dimen/episodes_list_item_height"
android:layout_height="@dimen/episodes_list_image_width"
/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical"
>
<TextView
android:id="@+id/tv_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<TextView
android:id="@+id/tv_release_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
/>
<TextView
android:id="@+id/tv_rating"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:drawableLeft="@drawable/ic_star_white_24dp"
android:drawablePadding="@dimen/view_padding_small"
/>
</FrameLayout>
<TextView
android:id="@+id/tv_description"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
</LinearLayout>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_seasons_list"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:focusable="false"
/>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_episodes_list"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="3"
android:focusable="false"
/>
</LinearLayout>
</FrameLayout>
item layout, used for both lists:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="@dimen/seasons_list_item_height"
android:orientation="horizontal"
android:focusable="true"
>
<TextView
android:id="@+id/tv_title"
android:layout_width="0dp"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:layout_weight="1"
/>
<TextView
android:id="@+id/tv_episodes_count"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:ems="10"
/>
</LinearLayout>
Digging through Google's Leanback library sources answered my payers. If you face the same trouble, just wrap your RecyclerViews with this and don't forget to set
private boolean mPersistFocusVertical = false;
if you want the focus to be persisted when searching horizontally, like in my layout.
Modify your main layout as below.
For directional navigation we can add properties like nextFocusDown, nextFocusLeft, nextFocusRight, nextFocusUp to focus relevant items as per our requirements.
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ImageView
android:id="@+id/iv_background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="false"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="27dp"
android:layout_marginLeft="48dp"
android:layout_marginRight="48dp"
android:layout_marginTop="27dp"
android:orientation="horizontal"
>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:focusable="false"
android:orientation="horizontal"
>
<ImageView
android:id="@+id/iv_poster"
android:layout_width="@dimen/episodes_list_item_height"
android:layout_height="@dimen/episodes_list_image_width"
/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical"
>
<TextView
android:id="@+id/tv_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<TextView
android:id="@+id/tv_release_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
/>
<TextView
android:id="@+id/tv_rating"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:drawableLeft="@drawable/ic_star_white_24dp"
android:drawablePadding="@dimen/view_padding_small"
/>
</FrameLayout>
<TextView
android:id="@+id/tv_description"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
</LinearLayout>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_seasons_list"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:focusable="false"
android:nextFocusDown="@+id/rv_episodes_list"
/>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_episodes_list"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="3"
android:focusable="false"
android:nextFocusUp="@+id/rv_seasons_list"
/>
</LinearLayout>
Hope this will solve your problem !!
来源：https://stackoverflow.com/questions/35203829/android-tv-move-focus-between-recyclerviews