在片段和活动之间导航

Question

我在片段和活动之间的导航遇到了麻烦，我使用了Android Studios2.2.3的自动生成模板，并自定义了它来在片段之间导航。

我添加了五个片段，并在导航抽屉活动中使用片段来使用本教程。

public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();
    Fragment fragment = null;
    Class fragmentClass = null;
    if (id == R.id.nav_schedule) {
     fragmentClass = ScheduleFragment.class;
    } else if (id == R.id.nav_assingment) {
        fragmentClass = AssignmentsFragment.class;
    } else if (id == R.id.nav_teachers) {
        fragmentClass = TeachersFragment.class;
    } else if (id == R.id.nav_score) {
        fragmentClass = ScoreFragment.class;
    } else if (id == R.id.nav_events) {
        fragmentClass = EventsFragment.class;
    } else if (id == R.id.nav_setting) {

    }else if (id == R.id.nav_about) {
        Intent intent = new Intent(getApplicationContext(),AboutActivity.class);
        startActivity(intent);
    }else if (id == R.id.nav_logout) {
        Intent i = new Intent(getApplicationContext(),LoginActivity.class);
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
        startActivity(i);
    }
         try {
             try {
                 fragment = (Fragment) fragmentClass.newInstance();
             } catch (InstantiationException e) {
                 e.printStackTrace();
             } catch (IllegalAccessException e) {
                 e.printStackTrace();
             }
             FragmentManager fragmentManager = getSupportFragmentManager();
             fragmentManager.beginTransaction().replace(R.id.container, fragment).commit();
         }catch (android.app.Fragment.InstantiationException e){
             e.printStackTrace();
         }
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

Answer 1

您必须在清单中定义活动。