我正在尝试从我的数据库中删除记录。我有这个Contact ListView列出了数据库中的记录。在itemLongClick上打开操作栏中的菜单，我可以在其中选择编辑或删除。当选择删除时，我打开一个对话框，询问他们是否确定要删除记录。如果是，那么我需要将所选项目的_id传递给DatabaseHandler，其中方法将删除RowID等于传递的_id的记录。
public class ActivityListContacts extends Activity {
// DatabaseHandler db = new DatabaseHandler(ActivityAddNewContact.this);
DatabaseHandler db;
final Context context = this;
private ActionMode mActionMode;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview_contacts);
populateContactList();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.contactlistmenu, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Take appropriate action for each action item click
switch (item.getItemId()) {
case R.id.addcontact:
Intent i = new Intent(this, ActivityAddNewContact.class);
startActivity(i);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void populateContactList() {
DatabaseHandler db = new DatabaseHandler(this);
TextView tvFullName = (TextView) findViewById(R.id.tvContactFullNameC);
// TextView tvCompany = (TextView)
// findViewById(R.id.tvContactListCompany);
Cursor cursor = db.fetchContacts();
// Allow activity to manage lifetime of the cursor.
// DEPRECATED! Runs on the UI thread, OK for small/short queries.
startManagingCursor(cursor);
// Setup mapping from cursor to view fields:
String[] fromFieldNames = new String[] { db.KEY_NAMECONCAT, db.KEY_COMPANY };
int[] toViewIDs = new int[] { R.id.tvContactFullNameC, R.id.tvContactListCompany };
SimpleCursorAdapter myCursorAdapter = new SimpleCursorAdapter(this, // Context
R.layout.item_contactlist, // Row layout template
cursor, // cursor (set of DB records to map)
fromFieldNames, // DB Column names
toViewIDs // View IDs to put information in
);
// Set the adapter for the list view
ListView contactList = (ListView) findViewById(R.id.lvContacts);
contactList.setAdapter(myCursorAdapter);
db.close();
contactList
.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView parent,
View view, int position, long id) {
System.out.println("Long click");
startActionMode(modeCallBack);
view.setSelected(true);
Log.w("CONTACT", "Long click item " + id);
startActionMode.setTag(id);
return true;
}
});
}
private ActionMode.Callback modeCallBack = new ActionMode.Callback() {
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
mode.setTitle("Options");
mode.getMenuInflater().inflate(R.menu.contactlistdialog, menu);
return true;
}
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
int contactid = item.getItemId();
Log.w("CONTACT", "Contact selected is ID# " + contactid);
switch (contactid) {
case R.id.delete: {
// Delete the Contact Record
// First ask if you are sure you want to delete, If yes then
// delete, if No then dismiss
Log.w("CONTACT", "Switch Contact ID " + contactid);
AlertDialog.Builder alert = new AlertDialog.Builder(ActivityListContacts.this);
// set title
alert.setTitle(R.string.contact_alert_title);
// set dialog message
alert.setMessage(R.string.contact_alert_message);
alert.setCancelable(false);
alert.setPositiveButton(R.string.contact_alert_yes,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int contactid) {
// If YES then delete the contact from database
Log.w("CONTACT", "Contact passed to DB is ID# " + contactid);
db.deleteContact(contactid);
dialog.cancel();
}
}).setNegativeButton(R.string.contact_alert_no,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int contactid) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alert.create();
// show it
alertDialog.show();
mode.finish();
break;
}
case R.id.edit: {
// Edit the Contact Record
break;
}
default:
return false;
}
return false;
}
@Override
public void onDestroyActionMode(ActionMode mode) {
}
};
/**
* private void registerListClickCallback() { ListView contactList =
* (ListView) findViewById(R.id.lvContacts);
* contactList.setOnItemClickListener(new AdapterView.OnItemClickListener()
* {
*
* @Override public void onItemClick(AdapterView<?> parent, View view, int
* position, long id) {
*
* updateItemForId(id); } }); } private void updateItemForId(long
* idInDB) { Cursor cursor = db.getRow(idInDB); if
* (cursor.moveToFirst()) { long idDB =
* cursor.getLong(db.COL_ROWID); String name =
* cursor.getString(db.COL_NAME); int studentNum =
* cursor.getInt(db.COL_STUDENTNUM); String favColour =
* cursor.getString(db.COL_FAVCOLOUR);
*
* favColour += "!"; db.updateRow(idInDB, name, studentNum,
* favColour); } cursor.close(); populateContactList(); }
*
*
*
*
*
*
*
* }
**/
@Override
protected void onPause() {
super.onPause();
}
@Override
protected void onDestroy() {
super.onDestroy();
this.finish();
}
}
以上是目前的全班。 OnItemLongClick位于populateContactList（）中。在那里，我从适配器获得“长ID”。其中的日志消息显示该项目的正确RowID。现在我们知道id是正确的项目，我需要将该id一直传递给DialogBox Positive按钮，该按钮执行数据库处理程序中的删除记录。