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androidpaletteandroid-recyclerview

Android Palette in RecyclerView

Im planning to get every vibrant color from each bitmap in my RecyclerView and set it as a background to my text. so i tried the following :

        Picasso.with(ctx)
                .load(curs.getString(curs
                        .getColumnIndex(TimelineDatabase.KEY_IMAGE)))
                .into(holder.ivUserPost, new Callback() {

                    @Override
                    public void onSuccess() {
                        try {
                            Bitmap bitmap = ((BitmapDrawable) holder.ivUserPost
                                    .getDrawable()).getBitmap();
                            Palette palette = Palette.generate(bitmap);
                            Toast.makeText(ctx,
                                    palette.getVibrantColor().getRgb(),
                                    Toast.LENGTH_LONG).show();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }

However, no toast is shown, and i keep receiving a null pointer exception with the following logcat:

07-27 07:13:34.163: W/System.err(4900): java.lang.NullPointerException: Attempt to invoke virtual method 'int android.support.v7.graphics.PaletteItem.getRgb()' on a null object reference
07-27 07:13:34.163: W/System.err(4900):     at com.joy.timeline.Fetch$TimelineFetchAdapter$2.onSuccess(Fetch.java:354)
07-27 07:13:34.163: W/System.err(4900):     at com.squareup.picasso.RequestCreator.into(RequestCreator.java:514)
07-27 07:13:34.163: W/System.err(4900):     at com.joy.timeline.Fetch$TimelineFetchAdapter.onBindViewHolder(Fetch.java:344)
07-27 07:13:34.163: W/System.err(4900):     at com.joy.timeline.Fetch$TimelineFetchAdapter.onBindViewHolder(Fetch.java:1)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:2925)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:2527)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.LinearLayoutManager$RenderState.next(LinearLayoutManager.java:1425)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:999)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:524)
07-27 07:13:34.163: W/System.err(4900):     at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:1461)
07-27 07:13:34.164: W/System.err(4900):     at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:1600)
07-27 07:13:34.164: W/System.err(4900):     at android.view.View.layout(View.java:15273)
07-27 07:13:34.164: W/System.err(4900):     at android.view.ViewGroup.layout(ViewGroup.java:4763)
07-27 07:13:34.164: W/System.err(4900):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1069)
Solution

  • Obviously, Palette could not find vibrant color in your bitmap. That's why there is an NPE. You can try to ask palette to generate more colors - Palette p = Palette.generate(bitmap, 24);. But there is also no guarantee it will find a vibrant color.

    Unfortunately, there is no official Palette documentation so far. You can refer to this article for more information