从导航抽屉打开新碎片时的口吃

Question

My app uses a navigation drawer and loads a new fragment into my activity when a row is selected from the drawer. It works ok but there is substantial lag and stuttering on the drawer closing animation. What can I do to eliminate the lag?

public class MainActivity extends BaseActivity {

    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    public static MenuItem menuItem;
    public static MenuItem marketListItem;
    public static MenuItem mapItem;

    // nav drawer title
    private  CharSequence mDrawerTitle;

    // used to store app title
    private CharSequence mTitle;

    // slide menu items
    private String[] navMenuTitles;
    private TypedArray navMenuIcons;

    private ArrayList<NavDrawerItem> navDrawerItems;
    private NavDrawerListAdapter adapter;

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

        ActionBar bar = getActionBar();
        bar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#0E4D8B")));

        mTitle = mDrawerTitle = getTitle();

        // load slide menu items
        navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

        // nav drawer icons from resources
        navMenuIcons = getResources().obtainTypedArray(R.array.nav_drawer_icons);

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

        navDrawerItems = new ArrayList<NavDrawerItem>();

        // adding nav drawer items to array
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[6], navMenuIcons.getResourceId(6, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[7], navMenuIcons.getResourceId(7, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[8], navMenuIcons.getResourceId(8, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[9], navMenuIcons.getResourceId(9, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[10], navMenuIcons.getResourceId(10, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[11], navMenuIcons.getResourceId(11, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[12], navMenuIcons.getResourceId(12, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[13], navMenuIcons.getResourceId(13, -1)));
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[14], navMenuIcons.getResourceId(14, -1)));

        // recycle the typed array
        navMenuIcons.recycle();

        // setting the nav drawer list adapter
        adapter = new NavDrawerListAdapter(getApplicationContext(), navDrawerItems);
        mDrawerList.setAdapter(adapter);

        // enabling action bar app icon and set it as toggle button
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.drawable.ic_drawer,
                R.string.app_name, R.string.app_name) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                // calling onPrepareOptionsMenu() to show action bar icons
                invalidateOptionsMenu();
            }

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

        if(savedInstanceState == null) {
            // on first time display view for first nav item
            displayView(0);
        }

        mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
    }

    /**
     * Slide menu item click listener
     */
    private class SlideMenuClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            // display view for selected nav drawer item
            displayView(position);
        }
    }

    /**
     * Displaying fragment view for selected nav drawer list item
     */
    private void displayView(int position) {
        // update the main content by replacing fragments
        Fragment fragment = null;
        switch (position) {
            case 0:
                // Action Alerts
                fragment = new ActionAlertsFragment();
                break;
            case 1:
                // Ag News
                fragment = new AgNewsFragment();
                break;
            case 2:
                // Market Updates
                fragment = new MarketUpdatesFragment();
                break;
            case  3:
                // Tours & Conferences
                fragment = new ToursFragment();
                break;
            case 4:
                // KFB Magazine
                fragment = new KFBMagFragment();
                break;
            case 5:
                // Member Benefits
                fragment = new BenefitsFragment();
                break;
            case 6:
                // Ag Facts
                fragment = new AgFactsFragment();
                break;
            case 7:
                // Farm Markets
                fragment = new RSFMFragment();
                break;
            case 8:
                // Weather
                fragment = new WeatherLocationFragment();
                break;
            case 9:
                // Annual Meeting
                fragment = new AnnualMeetingFragment();
                break;
            case 10:
                // Media
                fragment = new MediaFragment();
                break;
            case 11:
                // My KYFB
                fragment = new MyKYFB();
                break;
            case 12:
                // About KYFB
                break;
            case 13:
                // Contact Info
                break;
            case 14:
                // Preferences
                break;
            default:
                break;
        }

        if(fragment != null) {
            FragmentManager fragmentManager = getFragmentManager();
            fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();

            // update selected item and title, then close the drawer
            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(navMenuTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);
        }
        else {
            // error in creating fragment
            Log.e("MainActivity", "Error in creating fragment");
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        menuItem = (MenuItem)menu.findItem(R.id.action_settings);
        marketListItem = (MenuItem)menu.findItem(R.id.marketList);
        mapItem = (MenuItem)menu.findItem(R.id.map);
        menuItem.setVisible(false);
        marketListItem.setVisible(false);
        mapItem.setVisible(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.action_settings:
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    /***
     * Called when invalidateOptionsMenu() is triggered
     */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // if nav drawer is opened, hide the action items
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

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

    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // sync the toggle state after onRestoreInstanceState has occurred
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // pass any configuration changes to the drawer toggle
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

Answer 1

Your fragment is likely doing a lot of work in onCreate().

But, in general, you should use delayed runnable with a ~250ms holdoff before launching the fragment, to allow the drawer time to close.

        // launch the target Activity after a short delay, to allow the close animation to play
    mHandler.postDelayed(new Runnable() {
        @Override
        public void run() {
            goToNavDrawerItem(itemId);
        }
    }, NAVDRAWER_LAUNCH_DELAY);

    mDrawerLayout.closeDrawer(Gravity.START);

You can find the example in more detail in the Google IO app code on Github: Google IO 2014 code

Answer 2

You could just perform the action in the onDrawerClosed() callback of the ActionBarDrawerToggle that you've attached as the DrawerListener for your NavigationDrawer.

Then you won't have to hardcode a delay in your app. After all there's no guarantee that the animation time for the drawer close animation will remain constant.

Answer 3

Please check out my own solution described here:

https://stackoverflow.com/a/29133407/928956

In my own solution i take advantage from

mDrawerLayout.setDrawerListener()

method.