Java将数据从一个片段的Lis​​tView传递到另一个片段

Question

Movie ListView Fragment Movie Info Fragment

What I have is an app that has a database of movies, in my first tab fragment I have a listview which has all the movies in my database. I want it so when I click a movie in the listview it grabs the movie's database id and moves to the next tab which displays the movie info.

Main Activity (The activity that holds my tabs view pager)

public class MainActivity extends AppCompatActivity {
    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setOffscreenPageLimit(1);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show();
            }
        });
    }

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

    @Override
    public boolean onOptionsItemSelected (MenuItem item){
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public static class SectionsPagerAdapter extends FragmentPagerAdapter {
        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    return new FragmentMain();
                case 1:
                    return new FragmentManuallyAddMovie();
                case 2:
                    return new FragmentAddInternetMovie();
            }
            return null;
        }

        @Override
        public int getCount() {
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "MOVIES";
                case 1:
                    return "ADD";
                case 2:
                    return "SEARCH";
            }
            return null;
        }
    }

    public static class PlaceholderFragment extends Fragment {
        private static final String ARG_SECTION_NUMBER = "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;
        }
    }
}

FragmentMain (Where the movies database is displayed in a listview)

public class FragmentMain extends Fragment implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, View.OnClickListener {

private MoviesDBHandler handler;
private SimpleCursorAdapter adapter;
private ListView lvMovies;

public FragmentMain() {
    // Required empty public constructor
}

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

    handler = new MoviesDBHandler(this.getActivity());

    v.findViewById(R.id.btn_delete_all_movies).setOnClickListener(this);

    lvMovies = (ListView) v.findViewById(R.id.lv_movies);
    lvMovies.setEmptyView(v.findViewById(R.id.tv_instructionsa));

    lvMovies.setOnItemClickListener(this);
    lvMovies.setOnItemLongClickListener(this);
    return v;
}

@Override
public void onResume() {
    super.onResume();
    String[] from = {MoviesDBHelper.MOVIES_TITLE, MoviesDBHelper.MOVIES_GENRE, MoviesDBHelper.MOVIES_YEAR, MoviesDBHelper.MOVIES_PLOT, MoviesDBHelper.MOVIES_RATING, MoviesDBHelper.MOVIES_RUNTIME, MoviesDBHelper.MOVIES_IMAGE_URL};
    int[] to = {R.id.tv_title, R.id.tv_genre, R.id.tv_year, R.id.tv_plot, R.id.tv_rating, R.id.tv_runtime, R.id.img_movie_poster};

    adapter = new SimpleCursorAdapter(this.getActivity(), R.layout.movie_list_item, handler.getMovies(), from, to, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);

    adapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
        @Override
        public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
            if(columnIndex == cursor.getColumnIndex(MoviesDBHelper.MOVIES_IMAGE_URL)) {
                DatabaseDownloadImage task = new DatabaseDownloadImage((ImageView) view);
                task.execute(cursor.getString(columnIndex));
                return true;
            }
            return false;
        }
    });
    lvMovies.setAdapter(adapter);
}

public class DatabaseDownloadImage extends AsyncTask<String, Integer, Bitmap> {

    private ImageView imageView;

    public DatabaseDownloadImage(ImageView imageView) {
        this.imageView = imageView;
    }

    @Override
    protected Bitmap doInBackground(String... params) {
        String address = params[0];
        HttpURLConnection connection = null;
        Bitmap b = null;

        try {
            URL url = new URL(address);
            connection = (HttpURLConnection) url.openConnection();

            if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                return null;
            }
            else {
                b = BitmapFactory.decodeStream(connection.getInputStream());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return b;
    }

    protected void onPostExecute(Bitmap bitmap) {
        if (bitmap == null) {
            return;
        }
        imageView.setImageBitmap(Bitmap.createScaledBitmap(bitmap, 120, 180, false));
    }
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        //Delete all movies from database
        case R.id.btn_delete_all_movies:
            AlertDialog deleteMovieDialog = new AlertDialog.Builder(this.getActivity()).create();
            deleteMovieDialog.setTitle("Delete All Movies?");
            deleteMovieDialog.setIcon(R.drawable.ic_delete);
            deleteMovieDialog.setButton(DialogInterface.BUTTON_POSITIVE, "No", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
            deleteMovieDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Yes", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    handler.deleteAllMovies();
                    adapter.changeCursor(handler.getMovies());
                }
            });
            deleteMovieDialog.show();
            break;
    }
}

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

}

@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, final long id) {
    AlertDialog deleteMovieDialog = new AlertDialog.Builder(this.getActivity()).create();
    deleteMovieDialog.setTitle("Delete Movie?");
    deleteMovieDialog.setIcon(R.drawable.ic_delete);
    deleteMovieDialog.setButton(DialogInterface.BUTTON_POSITIVE, "No", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {

        }
    });
    deleteMovieDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Yes", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            handler.deleteMovie(id);
            adapter.changeCursor(handler.getMovies());
        }
    });
    deleteMovieDialog.show();
    return true;
}

}

Answer 1

All Fragment-to-Fragment communication is done through the associated Activity. Two Fragments should never communicate directly.

http://developer.android.com/intl/es/training/basics/fragments/communicating.html

You can communicate the two fragments with a static variable in the MainActivity that you change in the first fragment and get the content of this variable in the second fragment.

Update:

Create Movie.class, to save all the data of a one movie:

public class Movie() {

    String title;
    String genre;
    int year;
    String plot;
    int rating;
    int runtime;
    String img;

    public Movie(String title, String genre, int year, String plot, int rating, int runtime, String img) {
        this.title=title;
        this.genre=genre;
        this.year=year;
        this.plot=plot;
        this.rating=rating;
        this.runtime=runtime;
        this.img=img;
    }

    public String getTitle() {
        return title;
    } 
    public void setTitle(String title) {
        this.title=title;
    }

    //The same for the other variables
}

and in your MainActivity create a static variable of Movie :

public static Movie movie;

In onClick method save the data of the movie:

MainActivity.movie=new Movie(title, genre, year,plot,rating,runtime,img);

And to get the movie in the second fragment:

String title=MainActivity.movie.getTitle();
String genre=MainActivity.movie.getGenre();
...