I want to make app look like Ultra Power Saving Mode (galaxy s5). it change screen only display black and white color. I don't know how to make it.
Can anyone give some advice or information about how to do this?
Thanks a lot.
Your basic idea is flawed.
Samsung had to build off of Android to make the
Ultra Power Saving Mode. This isn't something that you can just create yourself simply by creating a black and white app.
What happens if the battery drains away? Some start turning things off, like Wi-Fi or Bluetooth, or even just activate Airplane Mode. Lower the screen's brightness. A bunch of random, individual things all meant to give the battery just a little bit longer of a push.
Samsung wanted to make that easier, and take things a bit further, by including their Ultra Power Saving Mode in the Galaxy S5. It does all of those things, with some tweaks. Instead of lowering the screen's brightness only, it actually turns it grayscale, and gives you a black-and-white representation of your phone's display. So even if you do use an app, like respond to an important text message, it'll remain grayscale. It turns off things like Bluetooth and Wi-Fi. It will also turn off your phone's data connection when the display is off, and switch back on when you start using your phone.
Even the lock screen changes, as you'll no longer see the weather report there, and Samsung's fancy animation is gone, replaced by a simple indicator as to how to unlock the device. Once you do, the next screen is just a short six-item list of pre-approved applications that you can use while in the mode.
So there are MANY things that when all combined will save the battery of the device; changing the screen from color to gray-scale will not be a major improvement. Also, depending on how you implement it, you can actually be making the performance worse!!
Samsung has tweaked almost everything and tested everything to make sure that all the tweaks in that mode actually save battery power. That isn't going to be something that you will be doing by yourself.