How to write build time stamp into apk

Question

1. Making some changes in Android Contacts package
2. Using mm (make) command to build this application

Because I have to change and build this app again and again, so I want to add a build time stamp in the Contacts.apk to check the build time when we runn it in the handset.

As we know, when we run mm command, the Android.mk (makefile) in Contacts package will be called.

And now, we can get the build time using date-macro.

But how we can write this build time stamp into a file that our application can read at runtime?

Any suggestions?

Answer 1

Method which checks date of last modification of classes.dex, this means last time when your app's code was built:

  try{      ApplicationInfo ai = getPackageManager().getApplicationInfo(getPackageName(), 0);      ZipFile zf = new ZipFile(ai.sourceDir);      ZipEntry ze = zf.getEntry("classes.dex");      long time = ze.getTime();      String s = SimpleDateFormat.getInstance().format(new java.util.Date(time));      zf.close();   }catch(Exception e){   } 

Tested, and works fine, even if app is installed on SD card.

Answer 2

If you use Gradle, you can add buildConfigField with timestamp updated at build time.

android {     defaultConfig {         buildConfigField "long", "TIMESTAMP", System.currentTimeMillis() + "L"     } } 

Then read it at runtime.

Date buildDate = new Date(BuildConfig.TIMESTAMP);