片段中的意外令牌

Question

我正在尝试在片段中嵌入 if 语句，以验证某个联系人是否有电话号码。如果是这样，我想提取联系人数据。出于某种原因，无论我尝试在代码中的何处放置 if 语句，我都会在 Android Studio 中收到“意外令牌”错误/错误：尝试编译时类型的非法开始。

import android.provider.ContactsContract.Contacts;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.CursorAdapter;
import android.support.v4.widget.SimpleCursorAdapter;
import android.database.Cursor;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.app.ListFragment;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.content.Context;
public class ContactsFragment extends ListFragment implements LoaderCallbacks<Cursor> {

private CursorAdapter mAdapter;

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

    // create adapter once
    Context context = getActivity();
    int layout = android.R.layout.activity_list_item;
    Cursor c = null; // there is no cursor yet
    int flags = 0; // no auto-requery! Loader requeries.
    mAdapter = new SimpleCursorAdapter(context, layout, c, FROM, TO, flags);
}

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

    // each time we are started use our listadapter
    setListAdapter(mAdapter);
    // and tell loader manager to start loading
    getLoaderManager().initLoader(0, null, this);
}

// columns requested from the database
private static final String[] PROJECTION = {


        Contacts.HAS_PHONE_NUMBER,
        Contacts._ID, // _ID is always required
        Contacts.DISPLAY_NAME_PRIMARY // that's what we want to display
};

// and name should be displayed in the text1 textview in item layout

public String[] phone = { Contacts.HAS_PHONE_NUMBER};
if (phone > 0) {
private static final String[] FROM = { Contacts.DISPLAY_NAME_PRIMARY };
private static final int[] TO = { android.R.id.text1 };
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {

    // load from the "Contacts table"
    Uri contentUri = Contacts.CONTENT_URI;

    // no sub-selection, no sort order, simply every row
    // projection says we want just the _id and the name column
    return new CursorLoader(getActivity(),
            contentUri,
            PROJECTION,
            null,
            null,
            null);
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    // Once cursor is loaded, give it to adapter
    mAdapter.swapCursor(data);
}

@Override
public void onLoaderReset(Loader<Cursor> loader) {
    // on reset take any old cursor away
    mAdapter.swapCursor(null);
}

}

在这种情况下，ContactsContract.Contacts.HAS_PHONE_NUMBER 是一个值为 0 或 1 的字符串。我想从我的列表中删除所有电子邮件地址（因此我通过电话号码进行验证）。

谢谢！

Answer 1

您实际上不需要if 声明。为您的 CursorLoader 提供正确的选择参数。

下面的工作代码，解释见 cmets。

public class ContactsFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor> {

    private CursorAdapter mAdapter;

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

        // create adapter once
        Context context = getActivity();
        int layout = android.R.layout.activity_list_item;
        Cursor c = null; // there is no cursor yet
        int flags = 0; // no auto-requery! Loader requeries.
        mAdapter = new SimpleCursorAdapter(context, layout, c, FROM, TO, flags);
    }

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

        // each time we are started use our listadapter
        setListAdapter(mAdapter);
        // and tell loader manager to start loading
        getLoaderManager().initLoader(0, null, this);
    }

    // columns requested from the database
    private static final String[] PROJECTION = {
            ContactsContract.Contacts.HAS_PHONE_NUMBER,
            ContactsContract.Contacts._ID, // _ID is always required
            ContactsContract.Contacts.DISPLAY_NAME_PRIMARY // that's what we want to display
    };

    // and name should be displayed in the text1 textview in item layout

    public String[] phone = {ContactsContract.Contacts.HAS_PHONE_NUMBER};
    private static final String[] FROM = {ContactsContract.Contacts.DISPLAY_NAME_PRIMARY};
    private static final int[] TO = {android.R.id.text1};

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {

        // load from the "Contacts table"
        Uri contentUri = ContactsContract.Contacts.CONTENT_URI;

        // no sub-selection, no sort order, simply every row
        // projection says we want just the _id and the name column
        return new CursorLoader(getActivity(),
                contentUri,
                PROJECTION,
                ContactsContract.Contacts.HAS_PHONE_NUMBER + " =?", // This is selection string, were looking for records that HAS_PHONE_NUMER is 1
                new String[]{"1"}, // 1 means that contact has a phone number
                null);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        // Once cursor is loaded, give it to adapter
        mAdapter.swapCursor(data);
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
        // on reset take any old cursor away
        mAdapter.swapCursor(null);
    }
}