android DrawerLayout导航片段重新加载，无需单击DrawerLayout项目

Question

我正在创建具有DrawerLayout导航的简单应用程序。其中一个菜单项是My 。在My屏幕中，有一个按钮可以打开、更改密码、屏幕和相同的片段。如果我打开DrawerLayout的菜单并在不单击的情况下关闭它，那么‘Screen屏幕再次加载。

以下是我的代码

public class HomeActivity extends ActionBarActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;

private CharSequence mDrawerTitle;
private CharSequence mTitle;

private ArrayList<SideMenuEntity> listSideMenuItems;
private SideMenuAdapter adapterSideMenu;

Menu menu;
Fragment fragment;
AsyncTaskHelper loadFragmentTask;
int position, old_position;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);

    mTitle = mDrawerTitle = getTitle();

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.list_slidermenu);

    listSideMenuItems = new ArrayList<>();

    for(String str : Constant.SIDE_MENU_ITEMS)
    {
        listSideMenuItems.add(new SideMenuEntity(str));
    }

    // setting the nav drawer list adapter
    adapterSideMenu = new SideMenuAdapter(getApplicationContext(),listSideMenuItems);
    mDrawerList.setAdapter(adapterSideMenu);

    mDrawerList.setOnItemClickListener(new ListView.OnItemClickListener()
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id)
        {
            displayView(position);
        }
    });

    ActionBar actionbar = getSupportActionBar();
    actionbar.setDisplayHomeAsUpEnabled(true);
    actionbar.setHomeButtonEnabled(true);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.mipmap.ic_launcher,R.string.app_name, R.string.app_name)
    {
        public void onDrawerClosed(View view) {
            getSupportActionBar().setTitle(mTitle);
            invalidateOptionsMenu();

            if (fragment != null) {
                _setFragmentContainer(fragment, listSideMenuItems.get(position).title);
            }
        }

        public void onDrawerOpened(View drawerView) {
            getSupportActionBar().setTitle(mDrawerTitle);
            // calling onPrepareOptionsMenu() to hide action bar icons
            invalidateOptionsMenu();
        }
    };

    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null)
    {
        old_position = -1;
        displayView(-1);

        _setFragmentContainer(fragment, listSideMenuItems.get(position).title);
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    this.menu = menu;
    getMenuInflater().inflate(R.menu.menu_home_setting, menu);

    _setActionBarHomeVisible(false);

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // toggle nav drawer on selecting action bar app icon/title
    if (mDrawerToggle.onOptionsItemSelected(item)) {
        return true;
    }
    // Handle action bar actions click
    switch (item.getItemId())
    {
        case R.id.title_bar_home:
            displayView(0);
            return true;

        case R.id.title_bar_setting:
            _setFragmentContainer(new SettingFragment(), "Setting");               
        return true;

        default:
            return super.onOptionsItemSelected(item);
    }
}

/***
 * Called when invalidateOptionsMenu() is triggered
 */
@Override
public boolean onPrepareOptionsMenu(Menu menu)
{
    return super.onPrepareOptionsMenu(menu);
}

/**
 * Diplaying fragment view for selected nav drawer list item
 *
 */
protected void displayView(int p)
{
    position = p >= 0 ? p : 0;

    fragment = null;

    switch (position)
    {
        case Constant.SIDE_MENU_ITEM_DAHSHBOARD:
            fragment = new DashboardFragment();               
            break;

        case Constant.SIDE_MENU_ITEM_MY_PROFILE:              
            fragment = new MyProfileFragment();
            break;
    }

    mDrawerList.setItemChecked(position, true);
    mDrawerList.setSelection(position);
    mDrawerLayout.closeDrawer(mDrawerList);
}

@Override
public void setTitle(CharSequence title) {
    mTitle = title;
    getSupportActionBar().setTitle(mTitle);
}

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    mDrawerToggle.syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    mDrawerToggle.onConfigurationChanged(newConfig);
}

/**-------------- private functions ---------------------*/

public void _setFragmentContainer(Fragment fragment, String title)
{
    FragmentManager fragmentManager = getSupportFragmentManager();
    fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
    setTitle(title);
}

}

Answer 1

尝试添加超级构造函数：

public void onDrawerClosed(View view) {
    super.onDrawerClosed(view);
    getSupportActionBar().setTitle(mTitle);
    invalidateOptionsMenu();

    if (fragment != null) {
        _setFragmentContainer(fragment, listSideMenuItems.get(position).title);
    }
}

public void onDrawerOpened(View drawerView) {
    super.onDrawerOpened(drawerView);
    getSupportActionBar().setTitle(mDrawerTitle);
    // calling onPrepareOptionsMenu() to hide action bar icons
    invalidateOptionsMenu();
}

Answer 2

我自己解决问题。实际上，每当DrawerLayout关闭时，onDrawerClosed事件就会触发，然后我只在_setFragmentContainer()函数之后空出片段变量

if (fragment != null) 
{
   _setFragmentContainer(fragment, listSideMenuItems.get(position).title);
   fragment = null;
}

现在DrawerLayout菜单关闭了，因为片段为null，所以它不会再次加载片段。