Image resolution for mdpi, hdpi, xhdpi and xxhdpi

Question

I have a background for my app in resolutions 720x1280 pixels, 1080x1920 pixels and 1440x2560 pixels.

In which folders (mdpi, hdpi, xhdpi and xxhdpi) should I put ea

Answer 1

Your inputs lack one important information of device dimension. Suppose now popular phone is 6 inch(the diagonal of the display), you will have following results

DPI: Dots per inch - number of dots(pixels) per segment(line) of 1 inch. DPI=Diagonal/Device size

Scaling Ratio= Real DPI/160. 160 is basic density (MHDPI)

DP: (Density-independent Pixel)=1/160 inch, think of it as a measurement unit