小编Inf*_*ixd的帖子

我是 Android 应用程序开发的新手，需要一些帮助。我注意到当我WebView使用导航选项卡尝试我的片段时，它们保持它们的状态很好，但是当我切换到使用导航抽屉时，每次我点击一个抽屉项目，然后点击我已经加载的抽屉项目回到那个抽屉项目，它只是重新加载WebView.

主要活动代码：

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    NavigationView navigationView = null;
    Toolbar toolbar = null;

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

        //Set the fragment initially
        MainFragment fragment = new MainFragment();
        android.support.v4.app.FragmentTransaction fragmentTransaction =
                getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.fragment_container, fragment);
        fragmentTransaction.commit();

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);

        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        navigationView = (NavigationView) findViewById(R.id.nav_view);

        //How to change elements in the …