How to hide status bar?

Question

How can I hide the status bar for a specific activity?

I found this similar question, but none of the answers worked for me. The app just crashed every time I tried

Answer 1

if (Build.VERSION.SDK_INT < 16)//before Jelly Bean Versions
{ 
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                         WindowManager.LayoutParams.FLAG_FULLSCREEN);
}
else // Jelly Bean and up
{ 
    View decorView = getWindow().getDecorView();
    // Hide the status bar.
    int ui = View.SYSTEM_UI_FLAG_FULLSCREEN;
    decorView.setSystemUiVisibility(ui);

    //Hide actionbar
    ActionBar actionBar = getActionBar();
    actionBar.hide();
}