回收者视图中的Android高亮圆圈

Question

Samsung Health Screenshot

I'm making a bar chart that shows a bar and a date using a recycler view that scrolls horizontally. And I'm wondering how I can create something like the black highlight circle in Samsung health?

I thought of setting a background for the date and set the background visible only when the item is in the center of the screen, but I found the Samsung's black circle doesn't just show up or disappear with the date as shown in the picture. How did it achieve the effect to change the part of the color of the date when it is overlapping with the circle?

Thanks for the help.

Answer 1

There is one quick way of doing it using PotterDuff CLEAR mode. When you are drawing date text on top of black circle. Use clear mode to change the color of the overlapped text and use setLayerType(View.LAYER_TYPE_HARDWARE,null); while initializing your custom view.

You can learn about PotterDuff here