将捆绑数据从主要活动发送到片段

Question

我有两个选项卡上的片段活动，我正在尝试使用 bundle 将变量从主类发送到片段。

但我收不到任何信息，我只会得到空值。

感谢您的帮助！

public class DetailedInfo extends AppCompatActivity {

    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;


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

        /////INFO, I WANT TO SEND
        InfoFragment fragment = new InfoFragment ();
        Bundle args = new Bundle();
        args.putString("key", "text i want to send" );
        fragment.setArguments(args);
        ////


        //TABS setup
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        // Create the adapter that will return a fragment for each of the two
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

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

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

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

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

    }


    public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

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

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    return PicturesFragment.newInstance(position + 1);
                case 1:
                    return InfoFragment.newInstance(position + 1);


            }
            return null;

        }

        @Override
        public int getCount() {
            return 2;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "Pictures";
                case 1:
                    return "Info";

            }
            return null;
        }
    }

    public static class PicturesFragment extends Fragment {

        private static final String ARG_SECTION_NUMBER = "section_number";

        public static PicturesFragment newInstance(int sectionNumber) {
            PicturesFragment fragment = new PicturesFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

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

            return detailedpictures;
        }
    }

    public static class InfoFragment extends Fragment {

        private static final String ARG_SECTION_NUMBER = "section_number";

        public static InfoFragment newInstance(int sectionNumber) {
            InfoFragment fragment = new InfoFragment ();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState ) {
            View detailedinfo = inflater.inflate(R.layout.fragment_detailed_info, container, false);

            ////INFO, I WANT TO RECEIVE
            Bundle bundle = getArguments();
            String customtext = bundle.getString("key");
            TextView detailtext= (TextView)detailedinfo.findViewById(R.id.info);
            detailtext.setText(customtext);
            ////

            return detailedinfo;
        }
    }
}

Answer 1

由于您没有在片段上使用 sectionNumber，我建议如下：

public static class InfoFragment extends Fragment {

public static InfoFragment newInstance(String value) {
    InfoFragment fragment = new InfoFragment ();
    Bundle args = new Bundle();
    args.putInt("key", value);
    fragment.setArguments(args);
    return fragment;
}

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState ) {
    View detailedinfo = inflater.inflate(R.layout.fragment_detailed_info, container, false);

    ////INFO, I WANT TO RECEIVE
    Bundle bundle = getArguments();
    String customtext = bundle.getString("key");
    TextView detailtext= (TextView)detailedinfo.findViewById(R.id.info);
    detailtext.setText(customtext);
    ////

    return detailedinfo;
}

}

public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

private InfoFragment infoFragment;
private PictureFragment picFragment;

public SectionsPagerAdapter(FragmentManager fm, InfoFragment infoFrg, PictureFragment picFrg) {
    super(fm);
    this.infoFragment = infoFrg;
    this.picFragment  = picFrg;
}

@Override
public Fragment getItem(int position) {
    switch (position) {
        case 0:
            return infoFragment;
        case 1:
            return picFragment;
    }
    return null;
}

最后：

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

  /////INFO, I WANT TO SEND
  InfoFragment infoFragment = InfoFragment.newInstance("text I want to send");
  ////
  PictureFragment picFrament = PictureFragment.newInstance(0);

  //TABS setup
  Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
  setSupportActionBar(toolbar);
  getSupportActionBar().setDisplayHomeAsUpEnabled(true);
  // Create the adapter that will return a fragment for each of the two
  // primary sections of the activity.
  mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager(), infoFragment, picFragment);

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

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