0
我试图实现一个底部导航栏，当导航项被点击时改变片段。但是，当我点击导航栏项目时，碎片不会改变。使用log.d，我注意到没有调用onNavigationItemSelected。 我该如何解决这个问题？onNavigationItemSelected未被调用的底部导航栏
要注意，startFeedFragment，startScheduleFragment，& startSettingsFragment实现同样的方式，他们的工具栏中的按钮工作。我也参考了这个tutorial和这个question寻求帮助。
MainActivity.java
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setUpRecycler();
startFeedFragment();
BottomNavigationView bottomNavBar = (BottomNavigationView) findViewById(R.id.navigation);
bottomNavBar.bringToFront();
bottomNavBar.setOnNavigationItemSelectedListener(this);
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
Log.d("NAV BAR", "onNavigationItemSelected hit");
switch (item.getItemId()) {
case R.id.feedMenu:
startFeedFragment();
Log.d("NAV BAR", "feed");
break;
case R.id.myScheduleMenu:
startScheduleFragment();
Log.d("NAV BAR", "schedule");
break;
case R.id.settingsMenu:
startSettingsFragment();
Log.d("NAV BAR", "settings lol");
break;
default:
Log.d("NAV BAR", "false");
return false;
}
return true;
}
/**
* Switches out the fragment for {@link FeedFragment} and sets an appropriate title. startScheduleFragmens & startSettingsFragment are implemented the same way
*/
private void startFeedFragment()
{
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragmentContainer, new FeedFragment());
transaction.commit();
getSupportActionBar().setTitle(R.string.title_fragment_feed);
}
}
片段从XML文件
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<FrameLayout
android:id="@+id/fragmentContainer"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/navigation"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:itemBackground="@android:color/white"
app:itemIconTint="@color/colorPrimaryDark"
app:itemTextColor="@color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="@menu/bottom_nav"
android:elevation="8dp"/>
</android.support.constraint.ConstraintLayout>
</android.support.design.widget.CoordinatorLayout>
