How to store a boolean value using SharedPreferences in Android?

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(); 
Boolean statusLocked = prefs.edit().putBoolean("locked", true).commit();

if you dont care about the return value (status) then you should use .apply() which is faster because its asynchronous.

prefs.edit().putBoolean("locked", true).apply();

to get them back use

Boolean yourLocked = prefs.getBoolean("locked", false);

while false is the default value when it fails or is not set

In your code it would look like this:

boolean locked = true;
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(); 
if (locked) { 
//maybe you want to check it by getting the sharedpreferences. Use this instead if (locked)
// if (prefs.getBoolean("locked", locked) {
   prefs.edit().putBoolean("locked", true).commit();
} else {
   startActivity(new Intent(parent.getContext(), Tag1.class));
}