Question

我开发了一个有一个活动的应用程序，在这个活动中，在抽屉列表项目（侧面）中添加了一些片段。所以我的问题是当我打开任何抽屉片段项目然后按下后退按钮应用程序去所以当按下它的开放的珍贵碎片时，如何处理像3 - 2 -1这样的后退事件。

主要活动代码

    public class MainActivity extends FragmentActivity {
    private DrawerLayout DrawerLayout;
    private ListView DrawerList;
    private ActionBarDrawerToggle DrawerToggle;

    private CharSequence DrawerTitle;

    private CharSequence Title;

    private String[] MenuTitles;
    private TypedArray MenuIcons;

    private DrawerListAdapter adapter;
    private ArrayList<DrawerItem> DrawerItems;

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

        Title = DrawerTitle = getTitle();

        MenuTitles = getResources().getStringArray(R.array.drawer_items);

        MenuIcons = getResources().obtainTypedArray(R.array.drawer_icons);

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

        DrawerItems = new ArrayList<DrawerItem>();

        DrawerItems.add(new DrawerItem(MenuTitles[0], MenuIcons.getResourceId(
                0, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[1], MenuIcons.getResourceId(
                1, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[2], MenuIcons.getResourceId(
                2, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[3], MenuIcons.getResourceId(
                3, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[4], MenuIcons.getResourceId(
                4, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[5], MenuIcons.getResourceId(
                5, -1)));

        DrawerItems.add(new DrawerItem(MenuTitles[6], MenuIcons.getResourceId(
                6, -1)));

        MenuIcons.recycle();

        DrawerList.setOnItemClickListener(new SlideMenuClickListener());

        adapter = new DrawerListAdapter(getApplicationContext(), DrawerItems);
        DrawerList.setAdapter(adapter);

        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        DrawerToggle = new ActionBarDrawerToggle(this, DrawerLayout,
                R.drawable.ic_drawer, R.string.app_name, R.string.app_name) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(Title);

                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(DrawerTitle);

                invalidateOptionsMenu();
            }
        };
        DrawerLayout.setDrawerListener(DrawerToggle);

        if (savedInstanceState == null) {

            displayView(0);
        }
    }

    private class SlideMenuClickListener implements
            ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                                long id) {

            displayView(position);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if (DrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }

        switch (item.getItemId()) {
            case R.id.action_settings:
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {

        boolean drawerOpen = DrawerLayout.isDrawerOpen(DrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    @SuppressLint("NewApi")
    private void displayView(int position) {

        Fragment fragment = null;
        switch (position) {
            case 0:
                fragment = new Home_Activity();
                break;
            case 1:
                fragment = new Activity_two();
                break;
            case 2:
                fragment = new Activity_three();
                break;
            case 3:
                fragment = new Activity_four();
                break;
            case 4:
                fragment = new Activity_five();
                break;
            case 5:
                fragment = new Activity_six();
                break;
            case 6:
                fragment = new Activity_seven();
                break;

            default:
                break;



FragmentTransaction transaction = getFragmentManager().beginTransaction();
            transaction.replace(R.id.frame_container, fragment);
            transaction.addToBackStack(null);
            transaction.commit();
        }

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

            DrawerList.setItemChecked(position, true);
            DrawerList.setSelection(position);
            setTitle(MenuTitles[position]);
            DrawerLayout.closeDrawer(DrawerList);
        } else {

            Log.e("MainActivity", "Error in creating fragment");
        }
    }

    @SuppressLint("NewApi")
    @Override
    public void setTitle(CharSequence title) {
        Title = title;
        getActionBar().setTitle(Title);
    }

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

        DrawerToggle.syncState();
    }


one fragment code...

    public class Activiy_three extends Fragment {

    private GridView gallery;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.activity_three_fragment,
                container, false);
        List<Item> Images = new ArrayList<Item>();
        //todo : develop as per date photo
        Images.add(new Item("Image 1", R.drawable.penguins));
        Images.add(new Item("Image 1", R.drawable.pulips));
        Images.add(new Item("Image 1", R.drawable.lighthouse));
        Images.add(new Item("Image 1", R.drawable.koala));
        Images.add(new Item("Image 1", R.drawable.jellyfish));
        Images.add(new Item("Image 1", R.drawable.hydrangeas));
        Images.add(new Item("Image 1", R.drawable.chrysanthemum));
        Images.add(new Item("Image 1", R.drawable.home));

        gallery = (GridView) v.findViewById(R.id.gridview);
        Global.photoAdapter = new PhotoAdapter(getActivity(), Images,false);
        gallery.setAdapter(Global.photoAdapter);

        gallery.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View view, int
                    position, long id) {

//                Intent i = new Intent(getActivity(), FullImageActivity.class);
//                i.putExtra(Global.Id, position);
//                startActivity(i);

                Fragment fragment = new FullImageActivity();
                FragmentManager fragmentManager = getFragmentManager();

                Bundle args = new Bundle();
                args.putInt(Global.Id, position);
                fragment.setArguments(args);

                fragmentManager.beginTransaction()
                        .replace(R.id.frame_container, fragment).commit();
            }
        });
        return v;
    }
}

Answer 1

您需要将片段添加到Backstack

FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, fragment);
transaction.addToBackStack(null);
transaction.commit();

您可以使用popBackStack()从堆栈中弹出片段

http://developer.android.com/reference/android/app/FragmentManager.html#popBackStack()

编辑：

你有什么

 default:
            break;

 FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.frame_container, fragment);
        transaction.addToBackStack(null);
        transaction.commit();
    }

应该是

private void displayView(int position) {

    Fragment fragment = null;
    switch (position) {
        case 0:
            fragment = new Home_Activity();
            break;
        case 1:
            fragment = new Activity_two();
            break;
        case 2:
            fragment = new Activity_three();
            break;
        case 3:
            fragment = new Activity_four();
            break;
        case 4:
            fragment = new Activity_five();
            break;
        case 5:
            fragment = new Activity_six();
            break;
        case 6:
            fragment = new Activity_seven();
            break;

        default:
            break;

    }

    if (fragment != null) {
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.frame_container, fragment);
        transaction.addToBackStack(null);
        transaction.commit();

        DrawerList.setItemChecked(position, true);
        DrawerList.setSelection(position);
        setTitle(MenuTitles[position]);
        DrawerLayout.closeDrawer(DrawerList);
    } else {

        Log.e("MainActivity", "Error in creating fragment");
    }
}

Answer 2

您可以使用在API级别14中引入的FragmentManager.BackStackEntry的getName方法

FragmentManager.BackStackEntry backEntry=getFragmentManager().getBackStackEntryAt(getActivity().getFragmentManager().getBackStackEntryCount()-1);
String str=backEntry.getName();
Fragment fragment=getFragmentManager().findFragmentByTag(str);

如何在android活动中处理抽屉列表片段中的后退事件

2 个答案: