Question

我正在尝试学习片段，我正在使用在eclipse中创建的Multiform项目模板。我在onListItemClick.中传递数据时遇到问题我将数据加载到SQL数据库中这是一个名称和地址列表。在列表视图中，我列出了名称，并且我希望在ListView中单击名称时列出名称和地址。可能有更好的方法来做到这一点，但我只是从这开始。

public class CustomerListFragment extends ListFragment {
       private Callbacks mCallbacks = sDummyCallbacks;
public interface Callbacks {

    public void onItemSelected(String id);
}

private static Callbacks sDummyCallbacks = new Callbacks() {
    public void onItemSelected(String id) {
    }
};

 @Override
public void onListItemClick(ListView listView, View view, int position, long id) {
    super.onListItemClick(listView, view, position, id);
    long myLong = values.get(position).getId();  
    mCallbacks.onItemSelected(String.valueOf(myLong));
}

在Detail片段中，我有以下内容。即使我从数据中传递Id，ARG_ITEM_ID也始终具有组件的id值。

public class CustomerDetailFragment extends Fragment {

public static final String ARG_ITEM_ID = "_id";
DataSource cusdatasource;
sqlCustomer selectedCustomer;

 @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    datasource = new DataSource(getActivity());
    datasource.open();

    if (getArguments().containsKey(ARG_ITEM_ID)) {
       mItem = DummyContent.ITEM_MAP.get(getArguments().getString(ARG_ITEM_ID));
    }
    selectedCustomer = datasource.getCustomer("here I need the _id from the list item clicked");

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.test_detail_customer, container, false);
    if (selectedCustomer != null) {
        ((TextView) rootView.findViewById(R.id.editText1)).setText(selectedCustomer.getName());
        ((TextView) rootView.findViewById(R.id.editText2)).setText(selectedCustomer.getStreet());
        ((TextView) rootView.findViewById(R.id.editText3)).setText(selectedCustomer.getCitySZ());
    }
    return rootView;
}

关于主要活动我有这个：

 public void onItemSelected(String id) {
        Bundle arguments = new Bundle();
        arguments.putString(CustomerDetailFragment.ARG_ITEM_ID, id);
        CustomerDetailFragment fragment = new CustomerDetailFragment();
        fragment.setArguments(arguments);
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.customer_detail_container, fragment)
                .commit();
 }

Answer 1

如果您尝试通过myLong界面将Callbacks值传递给DetailsFragment，那么您的表现并不正确。回调的想法是有人实现它并将自己注册为监听器，因此当用户单击调用实现的列表项时（而不只是有一个不执行任何操作的空实现）。您可以在活动的片段之间保留通信，以显示要管理的片段。例如：

public class CustomerListFragment extends ListFragment {
       private Callbacks mCallbacks;

public interface Callbacks {

    public void onItemSelected(String id);
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
            mCallbacks = (Callbacks) activity;
    } catch (ClassCastException ex) {
        Log.e(TAG, "Casting the activity as a Callbacks listener failed"
                + ex);
        mCallbacks = null;
    }
}


@Override
public void onListItemClick(ListView listView, View view, int position, long id) {
    long myLong = values.get(position).getId();  
    if (mCallbacks != null) {
        mCallbacks.onItemSelected(myLong);
    }
}
// ...

然后在您的活动中保存两个片段：

public class MainActivity extends FragmentActivity implements CustomerListFragment.Callbacks {

// ...

public void onItemSelected(Long id) {
    Bundle arguments = new Bundle();
    arguments.putLong(CustomerDetailFragment.ARG_ITEM_ID, id);
    CustomerDetailFragment fragment = new CustomerDetailFragment();
    fragment.setArguments(arguments);
    getSupportFragmentManager().beginTransaction()
            .replace(R.id.customer_detail_container, fragment)
            .commit();
}


//...

然后从传递给CustomerDetailFragment的参数中检索id：

long theId = -1;
if (getArguments().containsKey(ARG_ITEM_ID)) {
      theId = getArguments().getLong(ARG_ITEM_ID));
}
selectedCustomer = datasource.getCustomer(theId);

将Callback onListItemClick上的数据传递给片段

1 个答案: