Dreamingwhale Dreamingwhale - 2 months ago 20
Android Question

RecyclerView onCreateViewHolder called excessively when scrolling fast with DPAD

I'm developing on Amazon Fire TV.

Because it's a TV app(No touch), I need focusables inside row's layout to be able to navigate around.

I have a really simple Recyclerview with image, text, and a focusable. When I press up or down, it all scrolls and stuff correctly, but I noticed that when I navigate faster than scroll can keep up, it creates new viewholders (Off screen) and lags up the UI.

I have created an activity with Creation numbers on it. When I scroll slowly, the highest creation # is 10. But when I scroll fast, I get cards with creation number 60 in a second. This causes an enormous lag and the application drops a lot of frames. Is my approach totally wrong?

Use the code below to test this out.

/**
* Created by sylversphere on 15-04-15.
*/
public class LandfillActivity extends Activity{

private Context context;

private static int ticketNumber;
private static int getTicket(){
ticketNumber ++;
return ticketNumber;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
context = this;
setContentView(R.layout.landfill_activity);
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
GridLayoutManager glm = new GridLayoutManager(context, 2);
recyclerView.setLayoutManager(glm);
SickAdapter sickAdapter = new SickAdapter();
recyclerView.setAdapter(sickAdapter);
}

public class SickViewHolder extends RecyclerView.ViewHolder{
TextView ticketDisplayer;
public ImageView imageView;
public SickViewHolder(View itemView) {
super(itemView);
ticketDisplayer = (TextView) itemView.findViewById(R.id.ticketDisplayer);
imageView = (ImageView) itemView.findViewById(R.id.imageView);

itemView.findViewById(R.id.focus_glass).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
context.startActivity(new Intent(context, LouisVuittonActivity.class));
}
});
}
public void setTicket(int value){
ticketDisplayer.setText(""+value);
}
}

public class SickAdapter extends RecyclerView.Adapter<SickViewHolder>{

@Override
public SickViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
SickViewHolder svh = new SickViewHolder(getLayoutInflater().inflate(R.layout.one_row_element, null));
svh.setTicket(getTicket());
return svh;
}

@Override
public void onBindViewHolder(SickViewHolder holder, int position) {
String[] image_url_array = getResources().getStringArray(R.array.test_image_urls);
Picasso.with(context).load(image_url_array[position % image_url_array.length] ).fit().centerCrop().into(holder.imageView);
}

@Override
public int getItemCount() {
return 100000;
}
}
}


one_row_element.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">

<FrameLayout
android:layout_width="match_parent"
android:layout_height="200dp"
android:orientation="horizontal">

<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
android:src="@mipmap/sick_view_row_bg" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left|center_vertical"
android:layout_marginLeft="15dp"
android:orientation="horizontal">

<TextView
android:id="@+id/virusTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Creation #"
android:textColor="#fff"
android:textSize="40sp" />

<TextView
android:id="@+id/ticketDisplayer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1"
android:textColor="#fff"
android:textSize="40sp" />


</LinearLayout>

<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/focus_glass"
android:background="@drawable/subtle_focus_glass"
android:focusable="true"
android:focusableInTouchMode="true"/>

</FrameLayout>
</FrameLayout>


test_image_urls.xml (Urls not owned by me)

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="test_image_urls"
formatted="false">
<item>http://farm4.static.flickr.com/3175/2737866473_7958dc8760.jpg</item>
<item>http://farm4.static.flickr.com/3276/2875184020_9944005d0d.jpg</item>
<item>http://farm3.static.flickr.com/2531/4094333885_e8462a8338.jpg</item>
<item>http://farm4.static.flickr.com/3289/2809605169_8efe2b8f27.jpg</item>
<item>http://2.bp.blogspot.com/_SrRTF97Kbfo/SUqT9y-qTVI/AAAAAAAABmg/saRXhruwS6M/s400/bARADEI.jpg</item>
<item>http://fortunaweb.com.ar/wp-content/uploads/2009/10/Caroline-Atkinson-FMI.jpg</item>
<item>http://farm4.static.flickr.com/3488/4051378654_238ca94313.jpg</item>
<item>http://farm4.static.flickr.com/3368/3198142470_6eb0be5f32.jpg</item>
<item>http://www.powercai.net/Photo/UploadPhotos/200503/20050307172201492.jpg</item>
<item>http://www.web07.cn/uploads/Photo/c101122/12Z3Y54RZ-22027.jpg</item>
<item>http://www.mitravel.com.tw/html/asia/2011/Palau-4/index_clip_image002_0000.jpg</item>
<item>http://news.xinhuanet.com/mil/2007-05/19/xinsrc_36205041914150623191153.jpg</item>
<item>http://ib.berkeley.edu/labs/koehl/images/hannah.jpg</item>
<item>http://down.tutu001.com/d/file/20110307/ef7937c2b70bfc2da539eea9df_560.jpg</item>
<item>http://farm3.static.flickr.com/2278/2300491905_5272f77e56.jpg</item>
<item>http://www.pic35.com/uploads/allimg/100526/1-100526224U1.jpg</item>
<item>http://img.99118.com/Big2/1024768/20101211/1700013.jpg</item>
<item>http://farm1.static.flickr.com/45/139488995_bd06578562.jpg</item>
</string-array>
</resources>


subtle_focus

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_focused="true" android:drawable="@color/glass_focus"/>
<item android:drawable="@color/glass_normal"/>
</selector>


glass_normal is #9000
glass_focus is #0000

Your help is much appreciated. Thank you!

Answer

For anyone else looking for a quick hack, Do this. This will delay selection until it's been inflated and selected. I don't know how but it works. Just return null on onFocusSearchFailed.

 /**
 * Created by sylversphere on 15-04-22.
 */
public class SomeGridLayoutManager extends GridLayoutManager{

    private final Context context;

    public SomeGridLayoutManager(Context context, int spanCount) {
        super(context, spanCount);
        this.context = context;
    }

    public SomeGridLayoutManager(Context context, int spanCount, int orientation, boolean reverseLayout) {
        super(context, spanCount, orientation, reverseLayout);
        this.context = context;
    }

    @Override
    public View onFocusSearchFailed(View focused, int focusDirection, RecyclerView.Recycler recycler, RecyclerView.State state) {
        return null;
    }
}
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