将数据从片段传递到片段错误

Question

我使用 Bundle 在 Fragment 之间传递数据。但是，我运行陷入了一些问题。我的 Bundle 不工作，我不知道为什么。因为我做的一切都和以前一样。

这是我的 Activity:

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

    BottomNavigationView bottomNav = findViewById(R.id.lista_navigation);
    bottomNav.setOnNavigationItemSelectedListener(navListener);

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container_lista,
                new Tantargylista()).commit();
    }
}

private BottomNavigationView.OnNavigationItemSelectedListener navListener =
    new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment selectedFragment = null;

            switch (item.getItemId()) {
                case R.id.nav_tantargylista:
                    selectedFragment = new ObjectList();
                    break;
                case R.id.nav_dolgozatlista:
                    selectedFragment = new ExamList();
                    break;
            }

            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container_lista,
                    selectedFragment).commit();

            return true;
        }
    };
}

我的第一个片段：

View v;
DB mydb;
ListView listView;
String teszt;

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

    listView = (ListView)v.findViewById(R.id.Jegyekview);
    mydb = new DB(getActivity());

    final ArrayList<String> thelist = new ArrayList<>();
    Cursor data = mydb.getTantargynev();

    if (data.getCount() == 0) {
        Toast.makeText(getActivity(), "Empty", Toast.LENGTH_SHORT).show();

    } else {
        while (data.moveToNext()) {
            thelist.add(data.getString(0));
        ListAdapter listadapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, thelist);
        listView.setAdapter(listadapter);
    }

    listView.setOnItemClickListener(
            new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                    teszt = thelist.get(i);

                    Bundle bundle = new Bundle();
                    bundle.putString("test", teszt);

                    Fragment targyAdatok = new targyAdatok();

                    Fragment jegyekAllando = new jegyekAllando();
                    jegyekAllando.setArguments(bundle);
                    FragmentTransaction FragTan = getActivity().getSupportFragmentManager().beginTransaction();
                    FragTan.replace(R.id.jegyekMenu, targyAdatok);
                    FragTan.commit();
                }
            }
        });
    }

    return v;
}

第二个 Fragment 有一个 Button。如果按下Button，则第三个Fragment打开。

Button button = (Button)v.findViewById(R.id.elemzes);
elemzes.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        Fragment jegyekAllando = new jegyekAllando();
        FragmentTransaction FragTan2 = getFragmentManager().beginTransaction();
        FragTan2.replace(R.id.fragment_container_lista,jegyekAllando);
        FragTan2.commit();
    }
});

我的第三个片段：

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

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

    Bundle bundle = getArguments();
    String jegyAtlagSt = bundle.getString("test");
    //Here crash the program. :/

    return rootView;
}

Answer 1

我认为问题是您的第二个片段没有将包从第一个片段传递到这段代码中的第三个片段

Button button = (Button)v.findViewById(R.id.elemzes);
    elemzes.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Fragment jegyekAllando = new jegyekAllando();
            FragmentTransaction FragTan2 = getFragmentManager().beginTransaction();
            FragTan2.replace(R.id.fragment_container_lista,jegyekAllando);
            FragTan2.commit();
        }
    });

Answer 2

您在打开第三个 Fragment 时没有传递第二个 Fragment 的任何内容。因此，您需要执行以下操作。

Button button = (Button)v.findViewById(R.id.elemzes);
elemzes.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        Fragment jegyekAllando = new jegyekAllando();

        // Get a bundle
        Bundle bundle = new Bundle();
        bundle.putString("test", teszt);

        // Set as argument
        jegyekAllando.setArguments(bundle);

        // Begin the transaction
        FragmentTransaction FragTan2 = getFragmentManager().beginTransaction();
        FragTan2.replace(R.id.fragment_container_lista,jegyekAllando);
        FragTan2.commit();
    }
});

将数据从片段传递到片段错误

Passing data from Fragments to Fragments error

java

android

bundle

android-fragments