android - RecyclerView中的Android调色板

我打算从我的bitmap中的每个RecyclerView获取每种鲜艳的颜色，并将其设置为文本的背景。所以我尝试了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();
                        }
                    }

但是，没有显示吐司，并且我一直使用null pointer exception logcat接收following：

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)

最佳答案

显然，调色板在您的位图中找不到鲜艳的色彩。这就是为什么有NPE的原因。您可以尝试让调色板生成更多颜色-Palette p = Palette.generate(bitmap, 24);。但是也不能保证会找到鲜艳的色彩。

不幸的是，到目前为止还没有官方的Palette文档。您可以参考this article以获得更多信息。