我已经从使用了newView
和bindView
的ResourceCursorAdapter
切换到了使用仅有getView
方法的SimpleCursorAdapter
。现在我在onLoaderFinished
中遇到了错误,尽管我的适配器和游标对象都不为null,但是在adapter.swapCursor(cursor)
上给出了NullPointerException
。下面是我所有的代码。非常感谢任何帮助(我没剩多少头发可供拔了)。
import android.annotation.SuppressLint;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.ResourceCursorAdapter;
import android.util.Log;
import android.util.SparseBooleanArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.TextView;
public class ContactSelect extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor> {
private static final int LOADER_ID = 1;
private MyAdapter adapter;
private ListView list;
private View row;
private SparseBooleanArray checkedState = new SparseBooleanArray();
@SuppressLint({ "NewApi", "NewApi" })
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.activity_contact_select);
adapter = new MyAdapter(this, R.layout.contacts_select_row, null, null, null, 0);
getSupportLoaderManager().initLoader(LOADER_ID, null, this);
list = (ListView)findViewById(R.id.list);
list.setAdapter(adapter);
list.setEmptyView(findViewById(R.id.empty));
}
@SuppressLint("NewApi")
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
final String projection[] = new String[]{ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME};
final Uri uri = ContactsContract.Contacts.CONTENT_URI;
final String selection = ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1" +
" AND " + ContactsContract.Contacts.IN_VISIBLE_GROUP + " =1";
final String order = ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC";
final CursorLoader loader = new CursorLoader(this, uri, projection, selection, null, order);
return loader;
}
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
for(int i=0;i<cursor.getCount();i++){
checkedState.put(i, false);
}
adapter.swapCursor(cursor);
}
public void onLoaderReset(Loader<Cursor> loader) {
adapter.swapCursor(null);
}
private class MyAdapter extends SimpleCursorAdapter implements OnClickListener{
private CheckBox markedBox;
private TextView familyText;
private Context context;
private Cursor cursor;
public MyAdapter(Context context, int layout, Cursor c, String[] from,
int[] to, int flags) {
super(context, layout, c, from, to, flags);
this.context = context;
this.cursor = getCursor();
}
@Override
public View getView(int position, View view, ViewGroup group) {
final LayoutInflater li = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = li.inflate(R.layout.contacts_select_row, group, false);
view.setTag(cursor.getPosition());
view.setOnClickListener(this);
familyText = (TextView)view.findViewById(R.id.contacts_row_family_name);
markedBox = (CheckBox)view.findViewById(R.id.contacts_row_check);
familyText.setText(cursor.getString(cursor.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME)));
boolean currentlyChecked = checkedState.get(cursor.getPosition());
markedBox.setChecked(currentlyChecked);
setProgressBarIndeterminateVisibility(false);
return super.getView(position, view, group);
}
public void onClick(View view) {
int rowId = (Integer)view.getTag();
Log.d("OnClick", String.valueOf(rowId));
boolean currentlyChecked = checkedState.get(rowId);
markedBox.setChecked(!currentlyChecked);
checkedState.put(rowId, !currentlyChecked);
Log.d("checkedState", "checkedState(" + rowId + ") = " + checkedState.get(rowId));
}
}
}