SharedPreferences
/*============StartActivity.java============*/
public class StartActivity extends AppCompatActivity {
private static final String PREF_LOGIN = "LOGIN_PREF";
private static final String KEY_CREDENTIALS = "LOGIN_CREDENTIALS";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedPreferences preferences = getSharedPreferences(PREF_LOGIN, MODE_PRIVATE);
Intent intent = null;
if(preferences.contains(KEY_CREDENTIALS)){ //if user is currently logged in;
intent = new Intent(this, MainActivity.class);
}else { //if user is not yet logged in;
intent = new Intent(this, LoginActivity.class);
}
startActivity(intent);
}
}
/*============LoginActivity.java============*/
public class LoginActivity extends AppCompatActivity {
public static final String PREF_LOGIN = "LOGIN_PREF";
public static final String KEY_CREDENTIALS = "LOGIN_CREDENTIALS";
private Button loginButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
//...
loginButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//call login api...
//on your sucess callback; we save the credentials...
/*
SharedPreferences.Editor editor = getSharedPreferences(PREF_LOGIN, MODE_PRIVATE).edit();
editor.putString(KEY_CREDENTIALS, "DUMMY CREDENTIALS");
editor.commit();
*/
//on your failure callback; we clear the credentials...
/*
SharedPreferences.Editor editor = getSharedPreferences(PREF_LOGIN, MODE_PRIVATE).edit();
editor.clear();
editor.commit();
*/
}
});
}
</ProgAli>
