如何从可扩展列表视图中删除 child
How to remove child from Expandable Listview
我几乎需要的是,每当单击 child 时,我都需要出现一个警报,询问此人是否确定要删除提醒。如果他们按是,则需要将其删除,那是怎么做到的?我的代码如下。到目前为止,我尝试过的解决方案在尝试删除它时没有任何反应。例如,使用 listDataChild.remove(childPosition)
不起作用。
import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ExpandableListView;
import android.widget.Toast;
import androidx.appcompat.app.AlertDialog;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import Recycler.ExpandableListAdapter;
public class MainActivity extends Activity {
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();
Button home = findViewById(R.id.HomeBtn);
Button menu = findViewById(R.id.MenuBtn);
home.setBackgroundResource(R.drawable.home_button);
home.setBackgroundResource(R.drawable.btn_bg_yes_select);
menu.setBackgroundResource(R.drawable.menu_button);
menu.setBackgroundResource(R.drawable.btn_bg_not_select);
home.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
home.setBackgroundResource(R.drawable.btn_bg_yes_select);
menu.setBackgroundResource(R.drawable.btn_bg_not_select);
}
});
menu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent MainToMenu = new Intent(MainActivity.this, MenuActivity.class);
MainActivity.this.startActivity(MainToMenu);
overridePendingTransition(0, 0);
}
});
// get the listview
expListView = (ExpandableListView) findViewById(R.id.lvExp);
// preparing list data
prepareListData();
listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);
// setting list adapter
expListView.setAdapter(listAdapter);
//Expand Listview on Start
expListView.expandGroup(0);
expListView.expandGroup(1);
expListView.expandGroup(2);
// Listview on child click listener
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//Need it Here!
}
});
alertDialog.show();
return false;
}
});
}
private void prepareListData() {
// Adding child data
listDataHeader.add("Today");
listDataHeader.add("Yesterday");
listDataHeader.add("Older");
// Adding child data
List<String> TodayList = new ArrayList<String>();
TodayList.add("Today Example");
TodayList.add("Today Example");
List<String> YesterdayList = new ArrayList<String>();
YesterdayList.add("Yesterday Example");
YesterdayList.add("Yesterday Example");
List<String> OlderList = new ArrayList<String>();
OlderList.add("Old Example");
OlderList.add("Old Example");
listDataChild.put(listDataHeader.get(0), TodayList); // Header, Child data
listDataChild.put(listDataHeader.get(1), YesterdayList);
listDataChild.put(listDataHeader.get(2), OlderList);
}
}
public class ExpandableListAdapter extends BaseExpandableListAdapter {
private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;
public ExpandableListAdapter(Context context, List<String> listDataHeader,
HashMap<String, List<String>> listChildData) {
this._context = context;
this._listDataHeader = listDataHeader;
this._listDataChild = listChildData;
}
@Override
public Object getChild(int groupPosition, int childPosititon) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.get(childPosititon);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final String childText = (String) getChild(groupPosition, childPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.test_list_item, null);
}
TextView txtListChild = (TextView) convertView
.findViewById(R.id.lblListItem);
txtListChild.setText(childText);
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
}
@Override
public Object getGroup(int groupPosition) {
return this._listDataHeader.get(groupPosition);
}
@Override
public int getGroupCount() {
return this._listDataHeader.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String headerTitle = (String) getGroup(groupPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.test_list_group, null);
}
TextView lblListHeader = (TextView) convertView
.findViewById(R.id.lblListHeader);
lblListHeader.setTypeface(null, Typeface.BOLD);
lblListHeader.setText(headerTitle);
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
我可以通过单击进入 private void prepareListData()
来修复它。然后我添加了使用子位置和组位置的代码,它得到了要从列表数据中删除的文本。
代码-
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
String ValueToRemove = listDataChild.get(listDataHeader.get(groupPosition)).get(childPosition);
TodayList.remove(ValueToRemove);
YesterdayList.remove(ValueToRemove);
OlderList.remove(ValueToRemove);
listAdapter.notifyDataSetChanged();
}
});
alertDialog.show();
return false;
}
});
首先用groupPosition获取选中的组项列表,然后用childPosition从组列表中删除选中的项。
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
List<String> selectedGroupList = listDataChild.get(listDataHeader.get(groupPosition));
selectedGroupList.remove(childPosition);
listAdapter.notifyDataSetChanged();
}
});
alertDialog.show();
return false;
}
});
我几乎需要的是,每当单击 child 时,我都需要出现一个警报,询问此人是否确定要删除提醒。如果他们按是,则需要将其删除,那是怎么做到的?我的代码如下。到目前为止,我尝试过的解决方案在尝试删除它时没有任何反应。例如,使用 listDataChild.remove(childPosition)
不起作用。
import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ExpandableListView;
import android.widget.Toast;
import androidx.appcompat.app.AlertDialog;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import Recycler.ExpandableListAdapter;
public class MainActivity extends Activity {
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();
Button home = findViewById(R.id.HomeBtn);
Button menu = findViewById(R.id.MenuBtn);
home.setBackgroundResource(R.drawable.home_button);
home.setBackgroundResource(R.drawable.btn_bg_yes_select);
menu.setBackgroundResource(R.drawable.menu_button);
menu.setBackgroundResource(R.drawable.btn_bg_not_select);
home.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
home.setBackgroundResource(R.drawable.btn_bg_yes_select);
menu.setBackgroundResource(R.drawable.btn_bg_not_select);
}
});
menu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent MainToMenu = new Intent(MainActivity.this, MenuActivity.class);
MainActivity.this.startActivity(MainToMenu);
overridePendingTransition(0, 0);
}
});
// get the listview
expListView = (ExpandableListView) findViewById(R.id.lvExp);
// preparing list data
prepareListData();
listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);
// setting list adapter
expListView.setAdapter(listAdapter);
//Expand Listview on Start
expListView.expandGroup(0);
expListView.expandGroup(1);
expListView.expandGroup(2);
// Listview on child click listener
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//Need it Here!
}
});
alertDialog.show();
return false;
}
});
}
private void prepareListData() {
// Adding child data
listDataHeader.add("Today");
listDataHeader.add("Yesterday");
listDataHeader.add("Older");
// Adding child data
List<String> TodayList = new ArrayList<String>();
TodayList.add("Today Example");
TodayList.add("Today Example");
List<String> YesterdayList = new ArrayList<String>();
YesterdayList.add("Yesterday Example");
YesterdayList.add("Yesterday Example");
List<String> OlderList = new ArrayList<String>();
OlderList.add("Old Example");
OlderList.add("Old Example");
listDataChild.put(listDataHeader.get(0), TodayList); // Header, Child data
listDataChild.put(listDataHeader.get(1), YesterdayList);
listDataChild.put(listDataHeader.get(2), OlderList);
}
}
public class ExpandableListAdapter extends BaseExpandableListAdapter {
private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;
public ExpandableListAdapter(Context context, List<String> listDataHeader,
HashMap<String, List<String>> listChildData) {
this._context = context;
this._listDataHeader = listDataHeader;
this._listDataChild = listChildData;
}
@Override
public Object getChild(int groupPosition, int childPosititon) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.get(childPosititon);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final String childText = (String) getChild(groupPosition, childPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.test_list_item, null);
}
TextView txtListChild = (TextView) convertView
.findViewById(R.id.lblListItem);
txtListChild.setText(childText);
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
}
@Override
public Object getGroup(int groupPosition) {
return this._listDataHeader.get(groupPosition);
}
@Override
public int getGroupCount() {
return this._listDataHeader.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String headerTitle = (String) getGroup(groupPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.test_list_group, null);
}
TextView lblListHeader = (TextView) convertView
.findViewById(R.id.lblListHeader);
lblListHeader.setTypeface(null, Typeface.BOLD);
lblListHeader.setText(headerTitle);
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
我可以通过单击进入 private void prepareListData()
来修复它。然后我添加了使用子位置和组位置的代码,它得到了要从列表数据中删除的文本。
代码-
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
String ValueToRemove = listDataChild.get(listDataHeader.get(groupPosition)).get(childPosition);
TodayList.remove(ValueToRemove);
YesterdayList.remove(ValueToRemove);
OlderList.remove(ValueToRemove);
listAdapter.notifyDataSetChanged();
}
});
alertDialog.show();
return false;
}
});
首先用groupPosition获取选中的组项列表,然后用childPosition从组列表中删除选中的项。
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Remove Reminder");
alertDialog.setMessage("Are you sure you want to delete this reminder");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
List<String> selectedGroupList = listDataChild.get(listDataHeader.get(groupPosition));
selectedGroupList.remove(childPosition);
listAdapter.notifyDataSetChanged();
}
});
alertDialog.show();
return false;
}
});