单击导航抽屉中的项目时没有任何反应。我已尝试将代码块替换为onCreate()方法中的片段，以测试我的FragmentTransaction是否正常工作且效果良好。我不知道自己做错了什么。这是我从教程中学到的导航抽屉的代码
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
private DrawerLayout mDrawerLayout;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ActionBar actionbar = getSupportActionBar();
actionbar.setDisplayHomeAsUpEnabled(true);
actionbar.setHomeAsUpIndicator(R.drawable.ic_menu);
mDrawerLayout = findViewById(R.id.drawer_layout);
mDrawerLayout.addDrawerListener(
new DrawerLayout.DrawerListener() {
@Override
public void onDrawerSlide(@NonNull View drawerView, float slideOffset) {
}
@Override
public void onDrawerOpened(@NonNull View drawerView) {
}
@Override
public void onDrawerClosed(@NonNull View drawerView) {
}
@Override
public void onDrawerStateChanged(int newState) {
}
}
);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, mDrawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
mDrawerLayout.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView)findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
item.setChecked(true);
mDrawerLayout.closeDrawers();
int id = item.getItemId();
FragmentTransaction ft = getFragmentManager().beginTransaction();
switch (id) {
case R.id.nav_budget:
BudgetMain fragBudgetMain = new BudgetMain();
ft.replace(R.id.flContent, fragBudgetMain);
ft.addToBackStack(null);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
break;
case R.id.nav_expenses:
Expenses fragExp = new Expenses();
ft.replace(R.id.flContent, fragExp);
ft.addToBackStack(null);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
break;
case R.id.nav_selfassessment:
SelfAssessment fragSelf = new SelfAssessment();
ft.replace(R.id.flContent, fragSelf);
ft.addToBackStack(null);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
break;
case R.id.nav_mealcard:
MealCard fragMeal = new MealCard();
ft.replace(R.id.flContent, fragMeal);
ft.addToBackStack(null);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
break;
case R.id.nav_ranking:
Ranking fragRanking = new Ranking();
ft.replace(R.id.flContent, fragRanking);
ft.addToBackStack(null);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
break;
}
mDrawerLayout.closeDrawer(GravityCompat.START);
return true;
}
这是我的activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Use DrawerLayout as root container for activity -->
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:background="@drawable/gradient2">
<!-- Layout to contain contents of main body of screen (drawer will slide over this) -->
<!-- Container for contents of drawer - use NavigationView to make configuration easier -->
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:menu="@menu/drawer_view"
app:headerLayout="@layout/nav_header"/>
<include
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.v4.widget.DrawerLayout>
这是我的app_bar_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.activity.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?android:attr/actionBarSize"
android:background="@drawable/gradient"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="@+id/flContent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="?android:attr/actionBarSize"/>
</android.support.design.widget.CoordinatorLayout>
我的drawer_view.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<group android:checkableBehavior="single">
<item
android:id="@+id/nav_home"
android:icon="@drawable/ic_home"
android:title="Home"/>
<item
android:id="@+id/nav_budget"
android:icon="@drawable/ic_budget"
android:title="Budget"/>
<item
android:id="@+id/nav_expenses"
android:icon="@drawable/ic_expenses"
android:title="Expenses"/>
<item
android:id="@+id/nav_mealcard"
android:icon="@drawable/ic_mealcard"
android:title="Meal Card"/>
<item
android:id="@+id/nav_selfassessment"
android:icon="@drawable/ic_selfassessment"
android:title="Self-Assessment"/>
<item
android:id="@+id/nav_ranking"
android:icon="@drawable/ic_ranking"
android:title="Ranking"/>
</group>
</menu>
答案 0 :(得分：-1)
请试试这个：
mDrawerList.bringToFront();
mDrawerLayout.requestLayout();
所以onCreate（）方法看起来像这样：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ActionBar actionbar = getSupportActionBar();
actionbar.setDisplayHomeAsUpEnabled(true);
actionbar.setHomeAsUpIndicator(R.drawable.ic_menu);
mDrawerLayout = findViewById(R.id.drawer_layout);
mDrawerLayout.addDrawerListener(
new DrawerLayout.DrawerListener() {
@Override
public void onDrawerSlide(@NonNull View drawerView, float slideOffset) {
}
@Override
public void onDrawerOpened(@NonNull View drawerView) {
}
@Override
public void onDrawerClosed(@NonNull View drawerView) {
}
@Override
public void onDrawerStateChanged(int newState) {
}
}
);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, mDrawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
mDrawerLayout.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView)findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
mDrawerList.bringToFront();
mDrawerLayout.requestLayout();
}