We long know that nightly / night-time apps can extend the battery life of smartphones with OLED screens. This is true for Android, and it's true with the iPhone. This is because individual pixels need to continue working in dark areas of the screen, and to show real black, they practically do not use juice. How to SlashGear Google repeated this at this Android Dev Summit this week, showing a series of slides that compare the removal of different colors. (The company used these original data points for its Pixel smartphone.)
You can see that the white color is far and forefoot the most power. Therefore, Google admitted that highlighting white in all its apps and Android style guides is better than perfect. It is everywhere, and it does not change the design of Google's modified materials.
Fortunately, the company seems to recognize the value of the dark mode. YouTube and Android already have messages, and Google also opens this feature in your phone app and tests it on the mobile Google feed. Android can also set a dark theme for the Quick Settings drop down and App Drawer, but Google has not yet gone so far as adding the whole system to the night mode. (This is something Samsung intends to do with its new UI.)
As an example of a dark mode that comes to battery life, just look at the big difference below where Pixel is set to 100 percent brightness. The energy savings of the dark mode are obvious. Most often, I try to grapple with the traditional look of these apps, because I see white text in black, but I'm pleased to see that Google recognizes that the value is quite white. Choose where it makes sense.