我正在构建的应用程序使用导航抽屉android.support.v4.widget.DrawerLayout
,MainActivity
扩展android.support.v7.app.AppCompatActivity
。我有一个父片段,它被子片段替换。在父片段上,默认汉堡图标正确切换导航抽屉。在子片段上,使用此片段将汉堡包图标替换为后退箭头图标
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
((MainActivity)getActivity()).setSupportActionBar(toolbar);
在子片段上,单击按钮单击事件onOptionsItemSelected()
在onStop()
上再次显示父片段的汉堡图标。
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public void onStop() {
super.onStop();
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
MainActivity.toggle.syncState();
}
在父片段上,汉堡包图标现在显示正确,但在单击它时,导航抽屉不会再次显示。
谁能帮忙我做错了什么?
以下是相关文件:
主活动.java
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
public static ActionBarDrawerToggle toggle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
try {
Fragment fragment = (Fragment) ParentFragment.class.newInstance();
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_content, fragment).commit();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.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/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<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:headerLayout="@layout/nav_header_main"
app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
父片段.java
public class ParentFragment extends Fragment implements View.OnClickListener {
public static ParentFragment newInstance() {
ParentFragment fragment = new ParentFragment();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public void onClick(View v) {
int i = v.getId();
Fragment fragment = null;
if(i == R.id.child_fragment_button) {
fragment = new ChildFragment();
}
if(fragment != null) {
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_content, fragment)
.addToBackStack(null)
.commit();
}
}
}
子片段.java
public class ChildFragment extends Fragment {
private Toolbar toolbar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
// Show back button
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
((MainActivity)getActivity()).setSupportActionBar(toolbar);
}
@Override
public void onStop() {
super.onStop();
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
MainActivity.toggle.syncState();
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
我终于想出了解决方案。感谢这个答案。
以下是我所做的更改:
子片段.java
public class ChildFragment extends Fragment {
private Toolbar toolbar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
// Show back button
toggle = MainActivity.toggle;
toggle.setDrawerIndicatorEnabled(false);
toggle.setToolbarNavigationClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentManager manager = getActivity().getSupportFragmentManager();
manager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
toggle.setDrawerIndicatorEnabled(true);
}
});
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
toolbar.setNavigationIcon(((MainActivity)getActivity()).getDrawerToggleDelegate().getThemeUpIndicator());
}
@Override
public void onStop() {
super.onStop();
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
default:
return super.onOptionsItemSelected(item);
}
}
}