我有两个碎片FragmentHome
和FragmentAbout
,我在应用中添加了NavigationDrawer
,当我点击Home
时,它会打开FragmentHome
,而About
则会打开FragmentAbout
,当我打开FragmentAbout
时,我也将其添加到后退栈中。这很好地发挥了作用。
现在的问题是,当我点击About
并按下返回按钮时,它会回到FragmentHome
,但是NavigationDrawer
仍然显示About
作为选定项,我希望在从FragmentAbout
按下返回按钮时,将此选定项更改为Home
。
主页 Activity:
public class ActivityHome extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
Toolbar toolbar;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
// Toolbar
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Drawer layout
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.nav_drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.nav_drawer_open, R.string.nav_drawer_close);
assert drawer != null;
drawer.setDrawerListener(toggle);
toggle.syncState();
// Navigation view
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
assert navigationView != null;
navigationView.setNavigationItemSelectedListener(this);
// Open first menu item
navigationView.getMenu().performIdentifierAction(R.id.nav_home, 0);
// Set first item checked
navigationView.setCheckedItem(R.id.nav_home);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
final MenuItem menuItem = item;
// Check if menu item is selected
if (item.isChecked())
item.setChecked(false);
else
item.setChecked(true);
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_home) {
// Open home fragment
getSupportFragmentManager().beginTransaction()
.replace(R.id.frame_layout, new FragmentHome())
.commit();
} else if (id == R.id.nav_about) {
toolbar.setTitle("About");
// Open home fragment
getSupportFragmentManager().beginTransaction()
.replace(R.id.frame_layout, new FragmentAbout())
.addToBackStack(null)
.commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.nav_drawer_layout);
assert drawer != null;
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.nav_drawer_layout);
assert drawer != null;
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}}
主页碎片
public class FragmentHome extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_home, container, false);
}
@Override
public void onResume() {
super.onResume();
((AppCompatActivity)getActivity()).getSupportActionBar().setTitle(R.string.fragment_home_title);
}
}
FragmentAbout
的代码与 FragmentHome
相同,只是布局不同。
我在stackoverflow上搜索了很多,但尚未找到任何解决方案,所以如果有人知道如何做,请告诉我。