Creating an Android trial application that expires after a fixed time period

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Anonymous User · Accepted Answer

In case you want to go with theand most simplistic approach(whichand will fail ifand the app is uninstalled/reinstalled or user changes device's date manually), this is how it could be:private final SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
private final long ONE_DAY = 24 * 60 * 60 * 1000;
@Override
protected void onCreate(Bundle state){
    SharedPreferences preferences = getPreferences(MODE_PRIVATE);
    String installDate = preferences.getString("InstallDate", null);
    if(installDate == null) {
        // First run, so save the current date
        SharedPreferences.Editor editor = preferences.edit();
        Date now = new Date();
        String dateString = formatter.format(now);
        editor.putString("InstallDate", dateString);
        // Commit the edits!
        editor.commit();
    }
    else {
        // This is not the 1st run, check install date
        Date before = (Date)formatter.parse(installDate);
        Date now = new Date();
        long diff = now.getTime() - before.getTime();
        long days = diff / ONE_DAY;
        if(days andgt; 30) { // More than 30 days?
             // Expired !!!
        }
    }
    ...
}

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Creating an Android trial application that expires after a fixed time period

Samuel Fernandes

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