Всякий раз, когда я запускаю это приложение, все работает нормально. Но ничего не происходит, когда я нажимаю на параметры ящика. При отладке я понял, что метод onNavigationItemSelected даже не вызывается системой. Но когда я фиксирую транзакцию фрагмента в методе onCreate, все работает нормально. вот активность.java
ublic class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener{
DrawerLayout drawerLayout;
ActionBarDrawerToggle toggle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id._toolbar);
setSupportActionBar(toolbar);
NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
drawerLayout = findViewById(R.id.drawerlayout);
toggle = new ActionBarDrawerToggle(this, drawerLayout, R.string.nav_opened, R.string.nav_closed);
drawerLayout.addDrawerListener(toggle);
Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
displayView(R.id.nav_home);
}
@Override
protected void onPostCreate(@Nullable Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
toggle.syncState();
}
@Override
public void onConfigurationChanged(@NonNull Configuration newConfig) {
super.onConfigurationChanged(newConfig);
toggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
if(toggle.onOptionsItemSelected(item))
return true;
return super.onOptionsItemSelected(item);
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
displayView(item.getItemId());
return true;
}
@Override
public void onBackPressed() {
if(drawerLayout.isDrawerOpen(GravityCompat.START))
drawerLayout.closeDrawer(GravityCompat.START);
else
super.onBackPressed();
}
public void displayView(int viewId) {
Fragment fragment = null;
String title = getString(R.string.app_name);
switch (viewId) {
case R.id.nav_home:
//fragment = new HomeFragment();
break;
case R.id.nav_search:
fragment = new SearchFragment();
break;
case R.id.nav_list:
//fragment = new EatenListFragment();
break;
case R.id.nav_graph:
fragment = new SevenDayGraphFragment();
break;
case R.id.nav_settings:
//fragment = new SettingsFragment();
break;
}
if (fragment != null) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.commit();
}
// set the toolbar title
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle(title);
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawerlayout);
drawer.closeDrawer(GravityCompat.START);
}
}
А вот xml файл активности
<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawerlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:openDrawer="start"
tools:context=".MainActivity">
<include layout="@layout/appbar"
android:layout_height="match_parent"
android:layout_width="match_parent"/>
<com.google.android.material.navigation.NavigationView
android:id="@+id/nav_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/nav_header"
app:menu="@menu/activity_main_drawer">
</com.google.android.material.navigation.NavigationView>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent" android:id="@+id/content_frame"/>
<androidx.fragment.app.FragmentContainerView
android:id="@+id/fragment_container_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</androidx.drawerlayout.widget.DrawerLayout>
