启动画面确定，启动时加载哪个活动？

我正在制作一个启动画面，它Activity根据应用程序是否是第一次（或不）启动来确定要加载的内容。

代码在它自己的 Activity - 中运行MainActivity，它将充当启动画面。如果是第一次启动，我加载IntroActivity.. 如果之前启动过，我加载PrimaryActivity.

我有几个问题：

1) - 是否使用runOnUiThread正确的方法来做到这一点？

2) - 我在 StackOverflow 上研究了与启动画面相关的主题，建议使用 a Handler- 在我的特定用例中是否推荐使用？

3) -Thread一旦我确定要加载哪个活动，我是否应该关闭它，如果是，我应该怎么做？

奖金：

4) - 我打算最终使这个活动成为一个弹出式加载窗口..

实现这一目标的最简单方法是什么？

在此先感谢您提供的任何帮助！

我当前的代码如下所示：

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //  Make a Toast pop-up.
    Toast.makeText(MainActivity.this, "Checking Settings...", Toast.LENGTH_LONG).show();


    ////  BEGIN PREFERENCES CHECK  ////

    //  Set the wait time for the Splash screen.
    final int SPLASH_WAIT_TIME = 5000;

    //  Start new Thread to check for first start and load appropriate Activity.
    Thread t = new Thread(new Runnable() {
        @Override
        public void run() {

                //  Wait before continuing.
                try {
                    Thread.sleep(SPLASH_WAIT_TIME);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            //  Initialize SharedPreferences.
            SharedPreferences getPrefs = PreferenceManager
                    .getDefaultSharedPreferences(getBaseContext());

            //  Create a new boolean and preference and set it to true.
            boolean isFirstStart = getPrefs.getBoolean("firstStart", true);

            //  If the App has NEVER started before...
            if (isFirstStart) {

                //  Declare an Intent for loading IntroActivity.
                final Intent intentLoadIntro = new Intent(MainActivity.this, IntroActivity.class);

                //  Launch IntroActivity.
                runOnUiThread(new Runnable() {
                    @Override public void run() {
                        startActivity(intentLoadIntro);
                    }
                });

                //  Make a new Preferences Editor.
                SharedPreferences.Editor prefsEditor = getPrefs.edit();
                //  Edit Preference to make firstStart False so Intro never loads again.
                prefsEditor.putBoolean("firstStart", false);
                //  Apply the changes.
                prefsEditor.apply();

                //  Close MainActivity so the Back hardware button doesn't return to it.
                finish();

            }

            //  If the App HAS been started before...
            else {

                //  Declare an Intent for loading PrimaryActivity.
                final Intent intentLoadPrimary = new Intent (MainActivity.this, PrimaryActivity.class);

                //  Launch PrimaryActivity.
                runOnUiThread(new Runnable() {
                    @Override public void run() {
                        startActivity(intentLoadPrimary);
                    }
                });

                //  Close MainActivity so the Back hardware button doesn't return to it.
                finish();

            }

        }
    });

    //  Start Thread t to determine Activity to load after Splash (MainActivity).
    t.start();

//  END of onCreate.
}

//  End of MainActivity.
}