Java Saving Data In File Internal

[fireflies]

Hello
I am trying to read data from one activity, save it to a file... and when open another activity I will be able to read that file(by opening it).

I searched for tutorials, all they are showing on the same activity. I figured out how the code works.. but I'm not able to understand what will be the directory (parent directory while saving file). This is getting me confused that how can I make new file if no file still created, or if created then edit that file in the first activity... and how to even get the directory when I want to open it in another activity??

I learned from this page first: https://developer.android.com/training/data-storage/files.html

It is confusing because here

File file = new File(context.getFilesDir(), filename);

is getting error because of the "context". What will be the context??

 

[jedishrfu]

Try using the filesystem apis to help you determine the working directory. Often these are questions that to search for the answer will take longer than actually testing it on your device.

 

[jedishrfu]

Here's a simple Processing java example:

void setup() {
  File curdir = new File(".");
  println("curdir="+curdir.getAbsoluteFile());
}

 

[fireflies]

What about the code in this link? (Cause I already changed it all :( )

http://instinctcoder.com/read-and-write-text-file-in-android-studio/

But here it also says, that the file is saved in external memory... How can I change that to internal memory? (I haven't read the external memory part before I changed all the coding)

 

[jedishrfu]

Its okay to write to external memory that's the SD card. My code was to show you where it would write your file. The DOT means the current directory and the api tells you what directory is considered the current directory.

 

[fireflies]

Actually the app is kind of a diary. If I use external data then it is not secure anymore. Other applications can read the data too.

 

[jedishrfu]

encrypt it then

 

[fireflies]

Cannot it be made to internal storage?

 

[jedishrfu]

If you can read/write internal storage then so can other apps.

https://developer.android.com/training/data-storage/files.html

but if you want to protect them then use encryption or zip them up with encryption to save space and prevent anyone from reading them.

https://developer.android.com/reference/java/util/zip/package-summary.html

 

[fireflies]

Can you give me any link about how to encrypt or zip the files from the code?

 

[jedishrfu]

Here’s one

https://www.mkyong.com/java/how-to-compress-files-in-zip-format/