java - 在主 Activity 中调用 fragment 时出错

Question

我尝试在 onCreate 内的主要 Activity 中调用 fragment (菜单 fragment )。但它抛出错误(问题已解决)其他问题-> 调用 fragment 时，在获取数据时布局为空白。我在frameLayout 中调用了它。

这是 main.xml 的 xml 文件

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF">
    <!-- The main content view -->
    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:descendantFocusability="blocksDescendants"/>
    <!-- The navigation drawer -->
    <ListView android:id="@+id/list_view"
        android:layout_width="320dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:choiceMode="singleChoice"
        android:divider="@color/grey"
        android:dividerHeight="0dp"
        android:background="#000000"/>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/homeListView"
        android:background="#FFFFFF"
        android:divider="@color/grey"
        android:dividerHeight="1dp">
    </ListView>



</android.support.v4.widget.DrawerLayout>

Home.xml -> 菜单 fragment 布局

<?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:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Topic"
        android:textSize="30dp"
        android:textColor="#000000"
        android:fontFamily="sans-serif"
        android:id="@+id/topic"
        android:background="#ffffff"
        android:padding="10dp"
        android:textStyle="bold"
        android:visibility="gone"/>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/homeListView"
        android:background="#FFFFFF"
        android:divider="@color/grey"
        android:dividerHeight="1dp">
    </ListView>

</LinearLayout>

这是 Main.java，我试图在 onCreate 方法中替换为 fragment 。

public class Main extends FragmentActivity {
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    private CharSequence mDrawerTitle;
    private CharSequence mTitle;
    private String[] mDrawerMenu;

    @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mTitle = mDrawerTitle = getTitle();
        mDrawerMenu = getResources().getStringArray(R.array.menu);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.list_view);

        // set up the drawer's list view with items and click listener
        mDrawerList.setAdapter(new ArrayAdapter<String>(this,
                R.layout.custom_menu_list, mDrawerMenu));
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

        //Call Fragment
        android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
        android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        MenuFragment fragment = new MenuFragment();
        fragmentTransaction.replace(R.id.content_frame, fragment);
        fragmentTransaction.commit();

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu items for use in the action bar
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_activity_actions, menu);
        return super.onCreateOptionsMenu(menu);
    }


    //Action bar on item click events
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action buttons
        switch(item.getItemId()) {
            case R.id.menu_icon:
                // create intent to perform web search for this planet
                Log.d("Hello","Menu clicked");
                mDrawerLayout.openDrawer(mDrawerList);
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    /* The click listener for ListView in the navigation drawer */
    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @TargetApi(Build.VERSION_CODES.HONEYCOMB)
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int position, long id) {
            Log.d("Hello", String.valueOf(position));
            //Get the option name and compare
            String text = ((TextView) arg1.findViewById(android.R.id.text1)).getText().toString();
            android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
            android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            Bundle data = new Bundle();
            data.putString("Topic",text);
            if(position == 0){
                Log.d("Click","Home Clicked");
                MenuFragment fragment = new MenuFragment();
                fragment.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, fragment);
                fragmentTransaction.commit();

            }
            else if(position == 1){
                Log.d("Click","News Clicked 2");
                NewsFragment fragment = new NewsFragment();
                fragment.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, fragment, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
            else if(position == 2){
                Log.d("Click","Opinion Clicked");
                OpinionFragment OpF = new OpinionFragment();
                OpF.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, OpF, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
            else if(position == 3){
                Log.d("Click","Features Clicked");
                FeaturesFragment FeF = new FeaturesFragment();
                FeF.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, FeF, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
            else if(position == 4){
                Log.d("Click","Arts Clicked");
                ArtsFragment ArtsF = new ArtsFragment();
                ArtsF.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, ArtsF, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
            else if(position == 5){
                Log.d("Click","Sports Clicked");
                SportsFragment SportsF = new SportsFragment();
                SportsF.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, SportsF, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
            else if(position == 6){
                Log.d("Click","Opinion Clicked");
                BlogsFragment BlogsF = new BlogsFragment();
                BlogsF.setArguments(data);
                fragmentTransaction.replace(R.id.content_frame, BlogsF, String.valueOf(position));
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }


            mDrawerLayout.closeDrawer(mDrawerList);
        }
    }

}

这是 MenuFragment.java 类

public class MenuFragment extends Fragment {
    private ProgressDialog pDialog;// Progress Dialog
    ListView newsList;
    String my_url;
    LayoutInflater inflater;
    ArrayList<HashMap<String, String>> postList; //Declare Array
    private static String url = "http://wangeltmg.com/GKN_ADMIN/GET_POSTS/";
    GetNews.CustomAdapter CA;

    // JSON Node names
    private static final String TAG_ID = "id";
    private static final String POST_ALLPOSTS = "posts";
    private static final String POST_ID = "ID";
    private static final String POST_TITLE = "post_title";
    private static final String POST_CONTENT = "post_content";
    private static final String POST_DATE = "post_date";
    private static final String GUID = "guid";

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        View view =  inflater.inflate(R.layout.home, container, false);
        newsList = (ListView) view.findViewById(R.id.homeListView);
        TextView topic = (TextView) view.findViewById(R.id.topic);
        postList = new ArrayList<HashMap<String, String>>();
        //Get arguments
        Bundle args = getArguments();
        String mytopic = args.getString("Topic");
        newsList.setOnItemClickListener(new newsListClick());
        getActivity().getActionBar().setTitle("GannonKnightNews");
        //Set topic
        topic.setText(mytopic.toUpperCase());
        //Execute getContacts
        new GetNews().execute();

        return view;
    }

    public class newsListClick implements ListView.OnItemClickListener{

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Log.d("News List","Clicked " + id);
            String text = postList.get(position).get(GUID).toString();
            String post_title = postList.get(position).get(POST_TITLE).toString();
            String post_desc = postList.get(position).get(POST_CONTENT).toString();
            Log.d("PostCOntent--->",post_desc);
            android.support.v4.app.FragmentManager fragmentManager = getFragmentManager();
            android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

            Bundle data = new Bundle();
            data.putString("url", text);
            data.putString(POST_TITLE, post_title);
            data.putString(POST_CONTENT, post_desc);
            SinglePost singleFrag = new SinglePost();
            singleFrag.setArguments(data);
            fragmentTransaction.replace(R.id.content_frame, singleFrag);
            fragmentTransaction.commit();
        }
    }

    //Async Task
    private class GetNews extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(getActivity());
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {

            // Creating service handler class instance
            ServiceHandler sh = new ServiceHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
            Log.d("Strings", "Checking Json");
            Log.d("Response: ", "> " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);
                    // contacts JSONArray
                    JSONArray posts = null;
                    // Getting JSON Array node
                    posts = jsonObj.getJSONArray(POST_ALLPOSTS);

                    // looping through All Contacts
                    for (int i = 0; i < posts.length(); i++) {

                        JSONObject c = posts.getJSONObject(i);
                        Log.d("Post->",posts.getJSONObject(i).toString());

                        String id = c.getString(POST_ID);

                        Log.d("Post->ID",id);
                        String post_title = c.getString(POST_TITLE);
                        String post_content = c.getString(POST_CONTENT);
                        String guid = c.getString(GUID);
                        Log.d("GUID->",guid);
                        String post_date = c.getString(POST_DATE);

                        //String gender = c.getString(TAG_GENDER);

                        // tmp hashmap for single post
                        HashMap<String, String> post = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        post.put(POST_ID, id);
                        post.put(POST_TITLE, post_title);
                        post.put(POST_CONTENT, post_content);
                        post.put(GUID, guid);
                        post.put(POST_DATE, post_date);
                        post.put("ListCount",String.valueOf(i));

                        // adding contact to contact list
                        postList.add(post);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            } else {
                Log.e("ServiceHandler", "Couldn't get any data from the url");
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();

            // Updating parsed JSON data into ListView
               /*
            ListAdapter adapter = new SimpleAdapter(getActivity(), postList, R.layout.list_item,
                    new String[] { POST_TITLE,POST_CONTENT, GUID },
                    new int[] {R.id.email, R.id.mobile, R.id.guid });

            newsList.setAdapter(adapter);
            */
            CA = new CustomAdapter( getActivity(), R.layout.list_item, postList);
            newsList.setAdapter(CA);
        }


        public class CustomAdapter extends ArrayAdapter<HashMap<String, String>>{

            private final ArrayList<HashMap<String, String>> objects;

            public CustomAdapter(Context context, int resource, ArrayList<HashMap<String, String>> objects) {
                //something is wrong with super
                super(context, resource, objects);
                inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                this.objects = objects;
            }

            @Override
            public int getItemViewType(int position) {

                return position;
            }

            public View getView(int position, View convertView, ViewGroup Parent){
                //convertView = new ImageView();
                //System.out.println("getView " + position + " " + convertView + " type = " + type);
                if(convertView == null){

                    convertView = inflater.inflate(R.layout.list_item,null);

                }

                android.widget.ImageView postImage = (android.widget.ImageView) convertView.findViewById(R.id.img);
                int getListPos = newsList.getFirstVisiblePosition();
                //i set the count starting 0 and saved in the hashmap array
                //to compare the first result with the first position of listview
                int count = Integer.parseInt(objects.get(position).get("ListCount"));
                my_url = objects.get(position).get(GUID);
                if(getListPos == count) {
                    //LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                    convertView = inflater.inflate(R.layout.list_item_header,null);
                    TextView HeaderText = (TextView) convertView.findViewById(R.id.headertext);
                    TextView HeaderContent = (TextView) convertView.findViewById(R.id.headercontent);
                    TextView HeaderDate = (TextView) convertView.findViewById(R.id.header_date);
                    HeaderText.setText(objects.get(position).get(POST_TITLE).toUpperCase());
                    HeaderDate.setText(objects.get(position).get(POST_DATE));
                    HeaderContent.setText(objects.get(position).get(POST_CONTENT));
                    if(objects.get(position).get(GUID).equals("NULL")) {
                        postImage.setImageResource(R.drawable.default_bg);
                    }else{
                        new DownloadImageTask((ImageView) convertView.findViewById(R.id.img)).execute(my_url);
                    }
                }
                else{
                    //CHoose list item
                    //LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                    convertView = inflater.inflate(R.layout.list_item,null);
                    TextView thisview = (TextView) convertView.findViewById(R.id.email);
                    TextView postContent = (TextView) convertView.findViewById(R.id.mobile);
                    thisview.setText(objects.get(position).get(POST_TITLE).toUpperCase());
                    postContent.setText(objects.get(position).get(POST_CONTENT));
                    if(objects.get(position).get(GUID).equals("NULL")) {
                        postImage.setImageResource(R.drawable.default_bg);
                    }else{
                        new DownloadImageTask((ImageView) convertView.findViewById(R.id.img)).execute(my_url);
                    }
                }

                return convertView;
            }


        }//Custom Adapter

    }//END getnews Async Task

    private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return mIcon11;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }//

}

Answer 1

你应该改变

 String text = ((TextView) arg1.findViewById(android.R.id.text1)).getText().toString();

至

 String text = ((TextView) arg1.findViewById(R.id.text1)).getText().toString();

您的Textview ID 是text1。并且您正在尝试使用 android.R.id.text1。

这可能是导致您出现问题的原因之一。