Android：傳遞給方法時上下文為空

Question

在我的應用程序類中，InboxTabFragment的實例化如下所示：

InboxTabFragment.java

public class InboxFragmentTab extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor> {
private static final Uri SMS_CONTENT_URI = Uri.parse("content://sms");
private static final Uri SMS_INBOX_CONTENT_URI = Uri.withAppendedPath(SMS_CONTENT_URI, "inbox");
private static final String COLUMNS[] = new String[] {"person", "address", "body", "date", "type"};

SimpleCursorAdapter adapter;
Context context;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.inbox_layout, container, false);
    getLoaderManager().initLoader(0, null, this);
    return rootView;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
}

@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    CursorLoader loader = new CursorLoader(this.getActivity(), SMS_INBOX_CONTENT_URI, COLUMNS,
            null, null, null);
    return loader;
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor c) {
    ArrayList<Sms> result = new ArrayList<Sms>();

    if(c!=null) {
        for(boolean hasData = c.moveToFirst(); hasData; hasData=c.moveToNext()){
            boolean isSent = c.getInt(c.getColumnIndex("type")) == 2;
            String address = c.getString(c.getColumnIndex("address"));

            String sender = ContactManager.getContactName(context, address);
            String receiver = "Me";

            Sms sms = new Sms(address, c.getString(c.getColumnIndex("body")), new Date(Long.parseLong(c.getString(c.getColumnIndex("date")))), isSent ? sender : receiver);
            sms.setSender(isSent ? receiver : sender);
            result.add(sms);
        }
    }
    SmsAdapter adapter = new SmsAdapter(getActivity(), R.layout.row, result);
    setListAdapter(adapter);
}

@Override
public void onLoaderReset(Loader<Cursor> loader) {

}

問題發生在網上：

String sender = ContactManager.getContactName(context, address);

方法參數中傳遞的上下文為null，我不知道如何處理。 如果有人想幫助我解決此問題，我將不勝感激。

Answer 1

嘗試context = this.getActivity().getApplicationContext(); 在使用它之前。

Answer 2

您永遠不會將值分配給context對象。 加：

context = this.getActivity().getApplicationContext();