Question: Actually I'm handling 3 languages in my app so I have:

`values/strings.xml`

`values-it/strings.xml`

`values-de/strings.xml`

When I install the app, it is properly installed in the current language of the device.
But if I change the language of the device, the language of the app doesn't switch. I have to reinstall it to switch the language.

I've seent that this happens also to other apps, but not to all. The "big" ones (whatsapp, viber, all google's, etc) change.

So the question is: how can an app follow the device's language change ?

Answer: 
If the file is not fixed length, you are out of luck. Some function will have to read the file. If the file is fixed length, you can open the file, use the function `file.seek(line*linesize)`. Then read the file from there.
You can use the method `fileObject.seek(offset[, whence])`

```
#offset -- This is the position of the read/write pointer within the file.

#whence -- This is optional and defaults to 0 which means absolute file positioning, other values are 1 which means seek relative to the current position and 2 means seek relative to the file's end.

file = open("test.txt", "r")
line_size = 8 # Because there are 6 numbers and the newline
line_number = 5
file.seek(line_number * line_size, 0)
for i in range(5):
    print(file.readline())
file.close()

```

To this code I use the next file:

```
100101
101102
102103
103104
104105
105106
106107
107108
108109
109110
110111

```