Android determines whether the program is started for the first time

public class Welcome extends Activity {
  private final long SPLASH_LENGTH = 2000;
  Handler handler = new Handler();

  public void onCreate(Bundle savedInstanceState) {
    (savedInstanceState);
    setContentView(.farst_img);
    
    //Define a setting record how many times the APP is started!  !  !    SharedPreferences setting = getSharedPreferences(".hr_jie", 0);
    Boolean user_first = ("FIRST", true);
    if (user_first) {// Jump to the welcome page for the first time      ().putBoolean("FIRST", false).commit();
      tiaozhuanzhu();
    } else {//If it is the second startup, it will jump to the main page directly      tiaozhuanfu();
    }
  }
  
  public void tiaozhuanzhu(){ 
  (new Runnable() { //Use handler's postDelayed to achieve delay jump     
      public void run() {  
        Intent intent = new Intent(, Welcome_four.class);  
        startActivity(intent);  
        finish();    
      }  
    }, SPLASH_LENGTH);//Skip to the main interface of MainActivity in 2 seconds}
  
  public void tiaozhuanfu(){ 
  (new Runnable() {//Use handler's postDelayed to achieve delay jump     
      public void run() {  
        Intent intent = new Intent(, );  
        startActivity(intent);  
        finish();    
      }  
    }, SPLASH_LENGTH);//Redirect to the application welcome interface in 2 seconds}
}