Question

I need to build an application which enables me to edit the build.prop by using my own application. This is to optimize some of the values in the build.prop. Of course, I can edit this file using a file manager with root access. But my problem is, I need to edit this using an application that I create, and make it easy for the novice users to edit the file with recommended settings by my application. Please help me figure out this. Thanks for you time!

Answer 1

Something like this should work. Code hasn’t been tested and might need some changes

Requesting Superuser Access

process = Runtime.getRuntime().exec("su");
os = new DataOutputStream(process.getOutputStream());
os.writeBytes("mount -o remount rw /system/\n"); 
os.writeBytes("exit\n");
os.flush();
process.waitFor();

File file=new File("/system/build.prop");

Read file

FileInputStream fis = openFileInput("/system/build.prop");
String content = "";
byte[] input = new byte[fis.available()];
while (fis.read(input) != -1) {}
content += new String(input);

EDIT String content here.

Write file

DataOutputStream outstream= new DataOutputStream(new FileOutputStream(file,false));
String body = content;
outstream.write(body.getBytes());
outstream.close();

Remember to backup your build.prop in-case something goes wrong during editing.