我试图设置哪个片段应在启动时首先显示。为了确定这一点，我检查用户是否使用ParseUser.getCurrentUser（）登录以及设备上是否存在文件。在启动时，我想设置要显示的片段。为此，我将此代码放在onCreate方法的初始片段中。
if (ParseUser.getCurrentUser() != null) {
File f = new File(getActivity().getFilesDir() + "/display_store.bin");
if (f.exists() && !f.isDirectory()) {
ft.replace(R.id.container, new Display()).commit();
} else {
ft.replace(R.id.container, new CollectionFragment()).commit();
}
} else {
ft.replace(R.id.container, new Authentication()).commit();
}
我能够确定在启动时显示哪个片段。但是在我的导航抽屉中，当我选择“我的信息”和“我的显示”时，它仅将片段替换为“我的显示器”，而我无法从“导航抽屉”中显示“我的信息”。由于某种原因，它只是忽略了CollectionFragment。
主要活动：
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import com.microsoft.windowsazure.mobileservices.*;
import com.parse.Parse;
import com.parse.ParseUser;
import java.io.File;
import java.net.MalformedURLException;
public class MainActivity extends Activity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
private static MobileServiceClient mClient;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
Parse.enableLocalDatastore(this);
Parse.initialize(this, "api", "key");
try {
mClient = new MobileServiceClient("url", "key", this);
} catch (MalformedURLException e) {
e.printStackTrace();
}
}
public static MobileServiceClient getmClient() {
return mClient;
}
@Override
//Sets fragment
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
.commit();
}
public void onSectionAttached(int number) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
switch (number) {
case 1:
mTitle = "Home";
break;
case 2:
mTitle = "My Information";
ft.replace(R.id.container, new CollectionFragment()).commit();
break;
case 3:
mTitle = "My Display";
ft.replace(R.id.container, new Display()).commit();
break;
case 4:
mTitle = "Donate";
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.org"));
startActivity(browserIntent);
break;
case 5:
mTitle = "Settings";
break;
case 6:
mTitle = "Log Out";
ParseUser.logOut();
ft.replace(R.id.container, new Authentication()).commit();
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
private boolean runOnce = false;
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.form_welcome_screen_fragment, container, false);
return rootView;
}
@Override
public void onStart() {
super.onStart();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
if (ParseUser.getCurrentUser() != null) {
File f = new File(getActivity().getFilesDir() + "/display_store.bin");
if (f.exists() && !f.isDirectory()) {
ft.replace(R.id.container, new Display()).commit();
} else {
ft.replace(R.id.container, new CollectionFragment()).commit();
}
} else {
ft.replace(R.id.container, new Authentication()).commit();
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
导航抽屉片段：
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
/**
* Fragment used for managing interactions for and presentation of a navigation drawer.
* See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
* design guidelines</a> for a complete explanation of the behaviors implemented here.
*/
public class NavigationDrawerFragment extends Fragment {
/**
* Remember the position of the selected item.
*/
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
/**
* Per the design guidelines, you should show the drawer on launch until the user manually
* expands it. This shared preference tracks this.
*/
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
/**
* A pointer to the current callbacks instance (the Activity).
*/
private NavigationDrawerCallbacks mCallbacks;
/**
* Helper component that ties the action bar to the navigation drawer.
*/
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ListView mDrawerListView;
private View mFragmentContainerView;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public NavigationDrawerFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Read in the flag indicating whether or not the user has demonstrated awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
selectItem(mCurrentSelectedPosition);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of actions in the action bar.
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mDrawerListView = (ListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
});
mDrawerListView.setAdapter(new ArrayAdapter<String>(
getActionBar().getThemedContext(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1,
new String[]{
getString(R.string.title_section1),
getString(R.string.title_section2),
getString(R.string.title_section3),
getString(R.string.title_section4),
getString(R.string.title_section5),
getString(R.string.title_section6),
}));
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
return mDrawerListView;
}
public boolean isDrawerOpen() {
return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
}
/**
* Users of this fragment must call this method to set up the navigation drawer interactions.
*
* @param fragmentId The android:id of this fragment in its activity's layout.
* @param drawerLayout The DrawerLayout containing this fragment's UI.
*/
public void setUp(int fragmentId, DrawerLayout drawerLayout) {
mFragmentContainerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(
getActivity(), /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /* "open drawer" description for accessibility */
R.string.navigation_drawer_close /* "close drawer" description for accessibility */
) {
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
if (!isAdded()) {
return;
}
getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!isAdded()) {
return;
}
if (!mUserLearnedDrawer) {
// The user manually opened the drawer; store this flag to prevent auto-showing
// the navigation drawer automatically in the future.
mUserLearnedDrawer = true;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
}
getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
};
// If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
// per the navigation drawer design guidelines.
if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(mFragmentContainerView);
}
// Defer code dependent on restoration of previous instance state.
mDrawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
private void selectItem(int position) {
mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallbacks = (NavigationDrawerCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
}
}
@Override
public void onDetach() {
super.onDetach();
mCallbacks = null;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Forward the new configuration the drawer toggle component.
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// If the drawer is open, show the global app actions in the action bar. See also
// showGlobalContextActionBar, which controls the top-left area of the action bar.
if (mDrawerLayout != null && isDrawerOpen()) {
inflater.inflate(R.menu.main, menu);
showGlobalContextActionBar();
}
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// if (item.getItemId() == R.id.sort) {
// Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
// return true;
// }
return super.onOptionsItemSelected(item);
}
/**
* Per the navigation drawer design guidelines, updates the action bar to show the global app
* 'context', rather than just what's in the current screen.
*/
private void showGlobalContextActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setTitle(R.string.app_name);
}
private ActionBar getActionBar() {
return getActivity().getActionBar();
}
/**
* Callbacks interface that all activities using this fragment must implement.
*/
public static interface NavigationDrawerCallbacks {
/**
* Called when an item in the navigation drawer is selected.
*/
void onNavigationDrawerItemSelected(int position);
}
}
任何帮助将非常感激！！！
最佳答案
设置好抽屉后，请在onCreate(Bundle savedInstanceState)方法中写入以下内容：
mNavigationDrawerFragment.setUp(R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
if (savedInstanceState == null) {
// on first time to display view for first navigation item based on the number
onSectionAttached(2); // 2 is your fragment's number for "CollectionFragment"
}
请注意，您的
Fragment的数字为2。该数字是从您的public void onSectionAttached(int number)方法获得的。如果case 2:打开CollectionFragment，则您的Fragment的数字为2（因为case的数字为2）。然后，稍微更改您的onSectionAttached()：public void onSectionAttached(int number) {
// update the main content by replacing fragments
Fragment fragment = null;
switch (number) {
case 1:
mTitle = "Home";
break;
case 2:
mTitle = "My Information";
fragment = new CollectionFragment();
break;
case 3:
mTitle = "My Display";
fragment = new Display();
break;
case 4:
mTitle = "Donate";
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.org"));
startActivity(browserIntent);
break;
case 5:
mTitle = "Settings";
break;
case 6:
mTitle = "Log Out";
ParseUser.logOut();
fragment = new Authentication();
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, fragment).commit();
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
所以现在，您只需要调用
onSectionAttached(your fragment's number);以显示您想要的Fragment。