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Question

我的MainActivity在应用程序首次加载时显示welcomeScreen片段。当用户单击开始按钮时，它会切换到MainScreen Fragment。如果先前已按下开始按钮，如何跳过welcomeScreen片段？

MainActivity.java：

import layout.WelcomeScreenFragment;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    SearchView searchView;

    final static String[] NEEDED_PERMISSIONS = {Manifest.permission.WRITE_EXTERNAL_STORAGE,
            Manifest.permission.INTERNET,
            Manifest.permission.ACCESS_NETWORK_STATE};


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.my_toolbar);
        setSupportActionBar(toolbar);

        if (ContextCompat.checkSelfPermission(getApplicationContext(), NEEDED_PERMISSIONS[0])
                != PackageManager.PERMISSION_GRANTED &&
                ContextCompat.checkSelfPermission(getApplicationContext(), NEEDED_PERMISSIONS[1])
                        != PackageManager.PERMISSION_GRANTED &&
                ContextCompat.checkSelfPermission(getApplicationContext(), NEEDED_PERMISSIONS[2])
                        != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, NEEDED_PERMISSIONS, 808);
            Log.i(TAG, "onCreate: Requesting Permissions");

        }

//        Makes sure that the root_layout view is not null before doing anything
        if (findViewById(R.id.root_layout) != null) {

//            Makes sure that there's no saved instance before proceeding
            if (savedInstanceState == null) {
                FragmentManager fm = getSupportFragmentManager();
                FragmentTransaction manager = fm.beginTransaction();
                manager
                        .add(R.id.root_layout, WelcomeScreenFragment.newInstance(), "welcomeScreen")
                        .commit();
            }

        }
    }