In this case, the Android operating system also supports the download of fonts, so that if necessary, we download the relevant font and save it inside the Android operating system. Fonts are downloaded by the font provider and the font provider checks to see if the corresponding font is present within the operating system. If there is no relevant font, the font provider will download it and save it inside the Android operating system.It should be noted that all fonts that are similar or similar and have the same style are classified in one group. Fonts that have the same style and are similar to each other are grouped into groups such as font families. Users must consider unique specifications in order to use these similar fonts. In this way, they can choose their unique names or specify their characteristics. Android Support Library v26 uses API level 26 to support and use fonts. If we consider APIs whose level is less than 26, then we have to specify android: namespace and app: namespace for them. If we do not specify android: namespace and app : namespace for them and consider only android: namespace, they may not be displayed on lower than 26 operating systems. So in order for all fonts to be displayed with an API level less than 26, both android: namespace and app: namespace must be specified, otherwise if not specified, both fonts will not be displayed. APIs with a level below 26 do not support fonts and must be set to android: namespace and app: namespace in order to be displayed.
