所以我正在使用Navigation View实现一个带有5个抽屉（片段）的应用程序，每次点击抽屉时，它会加载/替换content某个layout选定的片段抽屉：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setupToolbar();
setupCollapsingToolbar();
setupNavigationDrawer();
}
public void setupToolbar() {
toolbar = (Toolbar) findViewById(R.id.toolbar);
if (toolbar != null) {
setSupportActionBar(toolbar);
}
}
public void setupCollapsingToolbar() {
collapsing_toolbar = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
collapsing_toolbar.setTitle(toolbar.getTitle());
}
public void setupNavigationDrawer() {
drawer_layout = (DrawerLayout) findViewById(R.id.drawer_layout);
navigation_view = (NavigationView) findViewById(R.id.navigation_view);
navigation_view.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
fragment_manager = getSupportFragmentManager();
fragment_transaction = fragment_manager.beginTransaction();
//fragment_transaction.setCustomAnimations(R.anim.fade_in, R.anim.fade_out);
menuItem.setChecked(true);
switch (menuItem.getItemId()) {
case R.id.cor:
fragment_transaction.replace(R.id.content, cor_fragment);
break;
case R.id.sched:
fragment_transaction.replace(R.id.content, sched_fragment);
break;
case R.id.eval:
fragment_transaction.replace(R.id.content, eval_fragment);
break;
case R.id.inc:
fragment_transaction.replace(R.id.content, inc_fragment);
break;
case R.id.clear:
fragment_transaction.replace(R.id.content, clear_fragment);
break;
}
mHandler = new Handler();
mHandler.removeCallbacksAndMessages(null);
int delay = 400;
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
fragment_transaction.addToBackStack(null);
fragment_transaction.commit();
}
}, delay);
// The millisecond delay is arbitrary and was arrived at through trial and error
drawer_layout.closeDrawers();
return true;
}
});
drawer_toggle = new ActionBarDrawerToggle(this, drawer_layout, toolbar, R.string.open_drawer, R.string.close_drawer) {
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
}
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
}
};
drawer_layout.setDrawerListener(drawer_toggle);
drawer_toggle.syncState();
drawer_layout.openDrawer(GravityCompat.START);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_toolbar, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
drawer_layout.openDrawer(GravityCompat.START);
return true;
case R.id.action_sign_out:
onSignOutClicked();
return true;
}
return super.onOptionsItemSelected(item);
}
因此，我尝试合并<CollapsingToolbarLayout>，当我尝试将其添加到fragment_main.xml时：
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<include layout="@layout/fragment_main"/>
<include layout="@layout/navigation_drawer"/>
</android.support.v4.widget.DrawerLayout>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar"
android:layout_width="match_parent"
android:layout_height="210dp"
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginBottom="32dp"
app:expandedTitleMarginEnd="64dp"
app:expandedTitleMarginStart="48dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/cover_nav_header"
android:fitsSystemWindows="true"
android:scaleType="centerCrop"
app:layout_collapseMode="parallax" />
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:background="@color/primary_dark"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:minHeight="?attr/actionBarSize"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:theme="@style/ActionBarPopupThemeOverlay"
app:menu="@menu/menu_toolbar"
app:layout_collapseMode="pin"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<!-- <android.support.v4.widget.NestedScrollView
android:id="@+id/nested_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior"> -->
<FrameLayout
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
android:orientation="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
<!-- </android.support.v4.widget.NestedScrollView> -->
</android.support.design.widget.CoordinatorLayout>
然后，仅 <FrameLayout> 会滚动！它根本不会影响Collasping Toolbar。
我尝试选择<NestedScrollView>（您可以从我评论的内容中看到）而不是<FrameLayout>或<LinearLayout>，但是内容赢了“ t被片段的布局取代，只能看到一个白色的空白区域。
我也试过嵌套它，<NestedScrollView>作为父项，<FrameLayout>作为孩子，但无济于事。
为什么Collapsing Toolbar不会崩溃有什么特别的原因吗？我错过了Collapsing Toolbar指南的内容吗？因为据我所知，所有这些都在.xml而且没有那么多Java干扰，只在.java文件中设置标题。
这是否与我 MainActivity.java 中的 fragment_transaction.replace() 有关？这只是我的推测。