Question

我有活动的布局：

    <fragment
        android:name="com.myapp.fragment1"
        android:id="@+id/fragment1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:layout="@layout/fragment1" />

    <fragment
        android:name="com.myapp.listfragment1"
        android:id="@+id/fragment2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

第一个片段（fragment1）扩展了Fragment，而第二个片段扩展了ListFragment。我没有为listfragment布局。

活动代码为：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_info);
}

在setContentView上抛出异常：

错误扩充类片段

ListFragment代码是：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setListAdapter(new MyListAdapter(getActivity(), prices));
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    getListView().setDivider(null);
}

在活动中拥有多个片段的正确方法是什么？

Answer 1

您可以使用SectionsPagerAdapter（滑动视图）或NavigationDrawer（导航抽屉）来执行此操作。我已经为我的一个应用程序使用了滑动视图。这是代码。

MainActivity.java

public class MainActivity extends AppCompatActivity implements ActionBar.TabListener {


    SectionsPagerAdapter mSectionsPagerAdapter;


    /**
     * The {@link ViewPager} that will host the section contents.
     */
    ViewPager mViewPager;

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


        // Set up the action bar.
        final ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());



        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        // When swiping between different sections, select the corresponding
        // tab. We can also use ActionBar.Tab#select() to do this if we have
        // a reference to the Tab.
        mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                actionBar.setSelectedNavigationItem(position);
            }
        });


        //Getting icons in icons veriable

        final int[] ICONS = new int[]{

                R.drawable.chat,
                R.drawable.friends,
                R.drawable.profile,



        };

        // For each of the sections in the app, add a tab to the action bar.
        for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
            // Create a tab with text corresponding to the page title defined by
            // the adapter. Also specify this Activity object, which implements
            // the TabListener interface, as the callback (listener) for when
            // this tab is selected.
            actionBar.addTab(
                    actionBar.newTab()
                            .setIcon(getResources().getDrawable(ICONS[i])).setTabListener(this));
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Take appropriate action for each action item click
        switch (item.getItemId()) {
            case R.id.action_search:
                // search action
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    @Override
    public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
        // When the given tab is selected, switch to the corresponding page in
        // the ViewPager.
        mViewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    }

    @Override
    public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }


        @Override
        public Fragment getItem(int index) {

            switch (index) {
                case 0:
                    // Top Rated fragment activity
                    return new ChatFragment();
                case 1:
                    return new FriendsFragment();
                    // Games fragment activity
                    //return new ProfileFragment();
                case 2:
                    // Movies fragment activity
                    //return new FriendsFragment();
                    return new ProfileFragment();

            }

            return null;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            Locale l = Locale.getDefault();
            switch (position) {
                case 0:
                    return getString(R.string.chat_tab).toUpperCase(l);
                case 1:
                    return getString(R.string.friends_tab).toUpperCase(l);
                case 2:
                    return getString(R.string.profile_tab).toUpperCase(l);
            }
            return null;
        }
    }

    /**
     * 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";

        /**
         * 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.fragment_main, container, false);
            return rootView;
        }
    }
}

FriendsFragment.java

public class FriendsFragment extends Fragment {

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

        View rootView = inflater.inflate(R.layout.fragment_friends, container, false);

        return rootView;
    }


    }

activity_main.xml中

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/pager"
    android:layout_width="match_parent" android:layout_height="match_parent"
    tools:context=".MainActivity" />

fragment_main.xml

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity$PlaceholderFragment">

    <TextView 
        android:id="@+id/section_label" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

fragment_friends.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent" android:layout_height="match_parent">

    <TextView
        android:id="@+id/email_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="@string/friends_tab"
        android:layout_gravity="center"
        android:gravity="center"/>

</LinearLayout>

这只是我项目的示例代码。您可以将自己的代码用于java或xml。在这里，我试图展示如何使用滑动视图调用MainActivity中的片段。希望它有所帮助。

在活动布局中填充类片段时出错

1 个答案: