0

私がやりたかったのは、フラグメントを使用してViewpager内のlistViewにデータを入力することですが、メインクラスが拡張されているため、ListFragmentを使用する必要がFragmentActivityありFragmentますListActivityか? LogCat でこれを指すmViewPager.setAdapter

public class tabs extends FragmentActivity implements ActionBar.TabListener {

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide fragments for each of the
     * three primary sections of the app. We use a {@link android.support.v4.app.FragmentPagerAdapter}
     * derivative, which will keep every loaded fragment in memory. If this becomes too memory
     * intensive, it may be best to switch to a {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    AppSectionsPagerAdapter mAppSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will display the three primary sections of the app, one at a
     * time.
     */
    ViewPager mViewPager;

    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.load_main_groups_activty);
        db = new DatabaseHandler(this);
        mContext = getBaseContext();

        //Need this for not getting null pointer exception 
        productsList = new  ArrayList<HashMap<String, ?>>();

        // Create the adapter that will return a fragment for each of the three primary sections
        // of the app.
        mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());

        // Set up the action bar.
        final ActionBar actionBar = getActionBar();

        // Specify that the Home/Up button should not be enabled, since there is no hierarchical
        // parent.
        actionBar.setHomeButtonEnabled(false);
        //actionBar.setDisplayShowTitleEnabled(false);

        // Specify that we will be displaying tabs in the action bar.
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Set up the ViewPager, attaching the adapter and setting up a listener for when the
        // user swipes between sections.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mAppSectionsPagerAdapter); //Logacat Error: at line 127
        mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // When swiping between different app sections, select the corresponding tab.
                // We can also use ActionBar.Tab#select() to do this if we have a reference to the
                // Tab.
                actionBar.setSelectedNavigationItem(position);
            }
        });

        // For each of the sections in the app, add a tab to the action bar.
        for (int i = 0; i < mAppSectionsPagerAdapter.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
            // listener for when this tab is selected.
            actionBar.addTab(
                    actionBar.newTab()
                            .setText(mAppSectionsPagerAdapter.getPageTitle(i))
                            .setTabListener(this));
        }
    }

    /**
     * A fragment that launches other parts of the demo application.
     */
public  static class LaunchpadSectionFragment extends ListFragment{



        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_section_launchpad, container, false);

            Holder holder = new Holder();

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

        LoadAllProducts task = new LoadAllProducts();
        task.execute();

        MySimpleArrayAdapter adapter = new MySimpleArrayAdapter(
                mContext, productsList,
                R.layout.load_main_groups_listview, FolderName);

        holder.lv= (ListView)rootView.findViewById(R.id.listView);

        holder.lv.setAdapter(adapter);
            return rootView;
        }

 class Holder {
            ListView lv;
            ViewPager pager;
        }


        class LoadAllProducts extends AsyncTask<String, String, String> {


            /**
             * Before starting background thread Show Progress Dialog
             * */
            @Override
            protected void onPreExecute() {
                super.onPreExecute();

                pDialog = new ProgressDialog(getActivity());
                pDialog.setMessage("Loading products. Please wait...");
                pDialog.setIndeterminate(false);
                pDialog.setCancelable(false);

                pDialog.show();

            }

            /**
             * getting All products from url
             * */
            protected String doInBackground(String... args) {
                // Building Parameters


                return null;
            }

            /**
             * After completing background task Dismiss the progress dialog
             * **/
            protected void onPostExecute(String file_url) {
                // dismiss the dialog after getting all products
                pDialog.dismiss();
                // updating UI from Background Thread


                getActivity().runOnUiThread(new Runnable() {
                    public void run() {
                        /**
                         * Updating parsed JSON data into ListView
                         * */


                        MySimpleArrayAdapter adapter = new MySimpleArrayAdapter(
                                mContext, productsList,
                                R.layout.load_main_groups_listview, FolderName);
                        setListAdapter(adapter);

                    }
                });

            }

        }
    }

load_main_groups_activtyと、メイン レイアウトのビューをカスタマイズするための別のレイアウトがありますload_main_groups_listview

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:orientation="vertical"  
                android:background="@color/white"     
                >
    <!-- Main ListView
         Always give id value as list(@android:id/list)
    -->
    <ListView
            android:id="@+id/listView"
            android:layout_width="fill_parent"
            android:layout_alignParentTop="true"
            android:layout_alignParentBottom="true"
            android:layout_height="wrap_content" 

            >
    </ListView>

</RelativeLayout>

LogCat:

07-18 10:27:34.366: E/AndroidRuntime(13948): FATAL EXCEPTION: main
07-18 10:27:34.366: E/AndroidRuntime(13948): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jinisys.restoplusordering/com.jinisys.restoplusordering.tabs}: java.lang.NullPointerException
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread.access$600(ActivityThread.java:130)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.os.Looper.loop(Looper.java:137)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread.main(ActivityThread.java:4745)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at java.lang.reflect.Method.invokeNative(Native Method)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at java.lang.reflect.Method.invoke(Method.java:511)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at dalvik.system.NativeStart.main(Native Method)
07-18 10:27:34.366: E/AndroidRuntime(13948): Caused by: java.lang.NullPointerException
07-18 10:27:34.366: E/AndroidRuntime(13948):    at com.jinisys.restoplusordering.tabs.onCreate(tabs.java:121)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.Activity.performCreate(Activity.java:5008)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-18 10:27:34.366: E/AndroidRuntime(13948):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
07-18 10:27:34.366: E/AndroidRuntime(13948):    ... 11 more
4

1 に答える 1

0

端的に言えば、ListActivity と ListFragment、またはそのバリアントを使用しないことです。

通常のフラグメントとアクティビティを使用するだけで、

  1. ListView をレイアウトに配置します。
  2. ArrayListAdapter (または BaseAdapter など) を拡張するプライベート クラス アダプターを作成します。
  3. フラグメントの onActivityCreated() でアダプターを割り当てます

ListActivity と ListFragment は非常に制限されており、非表示にしたり結合したりしてはならないものを非表示にして結合しようとします。

Vogellaには素晴らしいチュートリアルがあります

http://www.vogella.com/tutorials/AndroidListView/article.html

フラグメント内での使用と同じです。

于 2013-07-18T03:02:19.743 に答える