在Android中单击backpressed()方法时,如何更新可扩展的listview?
我有可扩展的列表视图。如果我单击groupview,我想找到子视图,如果子视图为零,那么它将转到另一个活动,否则它将显示所有子视图 这里我的代码有一个问题。例如,如果我的子视图大小为零,那么如果我单击groupview,它将进入另一个活动。然后我再次按下,然后单击另一个组视图,它显示我的子视图的上一个大小,这是最后一个组视图显示的大小(大小为零)。有人可以帮助我解决这个问题吗在Android中单击backpressed()方法时,如何更新可扩展的listview?,android,expandablelistview,Android,Expandablelistview,我有可扩展的列表视图。如果我单击groupview,我想找到子视图,如果子视图为零,那么它将转到另一个活动,否则它将显示所有子视图 这里我的代码有一个问题。例如,如果我的子视图大小为零,那么如果我单击groupview,它将进入另一个活动。然后我再次按下,然后单击另一个组视图,它显示我的子视图的上一个大小,这是最后一个组视图显示的大小(大小为零)。有人可以帮助我解决这个问题吗 public class ExpandableListActivity extends Activity {
public class ExpandableListActivity extends Activity {
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
int group_position,child_position;
boolean flag=false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.expandable_list);
// 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);
expListView.setOnGroupClickListener(new OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
if(child_position == 0){
// TODO Auto-generated method stub
Intent intent=new Intent(ExpandableListActivity.this,MainActivity.class);
startActivity(intent);
}
return false;
}
});
}
/*
* Preparing the list data
*/
private void prepareListData() {
listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();
// Adding child data
listDataHeader.add("Top 250");
listDataHeader.add("Now Showing");
listDataHeader.add("Coming Soon..");
// Adding child data
List<String> top250 = new ArrayList<String>();
top250.add("The Shawshank Redemption");
top250.add("The Godfather");
top250.add("The Godfather: Part II");
top250.add("Pulp Fiction");
top250.add("The Good, the Bad and the Ugly");
top250.add("The Dark Knight");
top250.add("12 Angry Men");
List<String> nowShowing = new ArrayList<String>();
nowShowing.add("The Conjuring");
nowShowing.add("Despicable Me 2");
nowShowing.add("Turbo");
nowShowing.add("Grown Ups 2");
nowShowing.add("Red 2");
nowShowing.add("The Wolverine");
List<String> comingSoon = new ArrayList<String>();
// comingSoon.add("2 Guns");
// comingSoon.add("The Smurfs 2");
// comingSoon.add("The Spectacular Now");
// comingSoon.add("The Canyons");
// comingSoon.add("Europa Report");
listDataChild.put(listDataHeader.get(0), top250); // Header, Child data
listDataChild.put(listDataHeader.get(1), nowShowing);
listDataChild.put(listDataHeader.get(2), comingSoon);
}
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.expand_list_item, null);
}
TextView txtListChild = (TextView) convertView
.findViewById(R.id.lblListItem);
txtListChild.setText(childText);
convertView.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent=new Intent(ExpandableListActivity.this,MainActivity.class);
startActivity(intent);
}
});
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
child_position=this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
group_position=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(final 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.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;
}
}
公共类ExpandableListActivity扩展活动{
可扩展列表适配器;
ExpandableListView解释视图;
列表列表数据头;
HashMapListDataChild;
int组位置、子位置;
布尔标志=假;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.expandable_列表);
//获取列表视图
expListView=(ExpandableListView)findViewById(R.id.lvExp);
//准备列表数据
prepareListData();
listAdapter=新的ExpandableListAdapter(此,listDataHeader,listDataChild);
//设置列表适配器
expListView.setAdapter(listAdapter);
expListView.setOnGroupClickListener(新OnGroupClickListener(){
@凌驾
公共布尔onGroupClick(ExpandableListView父视图、视图v、int-groupPosition、长id){
如果(子位置==0){
//TODO自动生成的方法存根
意向意向=新意向(ExpandableListActivity.this,MainActivity.class);
星触觉(意向);
}
返回false;
}
});
}
/*
*准备列表数据
*/
私有void prepareListData(){
listDataHeader=新的ArrayList();
listDataChild=newHashMap();
//添加子数据
添加(“前250名”);
添加(“现在显示”);
添加(“即将推出…”);
//添加子数据
List top250=新的ArrayList();
top250.添加(“肖申克的救赎”);
添加(“教父”);
top250.添加(“教父:第二部分”);
top250.添加(“低俗小说”);
添加(“好、坏、丑”);
添加(“黑暗骑士”);
添加(“12个愤怒的男人”);
List nowShowing=新建ArrayList();
现在显示。添加(“变戏法”);
添加(“卑鄙的我2”);
现在显示。添加(“Turbo”);
现在显示。添加(“成年人2”);
现在显示。添加(“红色2”);
现在显示。添加(“狼獾”);
List comingSoon=新建ArrayList();
//很快就来。添加(“2支枪”);
//很快就来。添加(“蓝精灵2”);
//即将到来。添加(“现在的壮观”);
//即将到来。添加(“峡谷”);
//即将出版。添加(“欧罗巴报告”);
listDataChild.put(listDataHeader.get(0),top250);//头,子数据
listDataChild.put(listDataHeader.get(1),现在显示);
listDataChild.put(listDataHeader.get(2),即将出现);
}
公共类ExpandableListAdapter扩展了BaseExpandableListAdapter{
私人语境(private Context)(私人语境);;
私有列表_listDataHeader;//头标题
//标题标题、子标题格式的子数据
私有HashMap_listDataChild;
公共ExpandableListAdapter(上下文、列表listDataHeader、,
HashMap listChildData){
这._context=context;
这。_listDataHeader=listDataHeader;
这。_listDataChild=listChildData;
}
@凌驾
公共对象getChild(int-groupPosition、int-ChildPosition){
返回此。_listDataChild.get(此。_listDataHeader.get(groupPosition))
.get(childpositionon);
}
@凌驾
公共长getChildId(int-groupPosition,int-childPosition){
返回子位置;
}
@凌驾
公共视图getChildView(int groupPosition,final int childPosition,
布尔值isLastChild、视图转换视图、视图组父级){
最终字符串childText=(字符串)getChild(groupPosition,childPosition);
if(convertView==null){
LayoutInflater infalInflater=(LayoutInflater)this.\u上下文
.getSystemService(上下文布局\充气机\服务);
convertView=infalInflater.充气(R.layout.expand\u list\u项,空);
}
TextView txtListChild=(TextView)convertView
.findviewbyd(R.id.lblListItem);
setText(childText);
setOnClickListener(新的OnClickListener()
{
@凌驾
公共void onClick(视图v){
//TODO自动生成的方法存根
意向意向=新意向(ExpandableListActivity.this,MainActivity.class);
星触觉(意向);
}
});
返回视图;
}
@凌驾
公共整数getChildrenCount(整数组位置){
child\u position=this.\u listDataChild.get(this.\u listDataHeader.get(groupPosition))
.size();
组位置=组位置;
返回此。_listDataChild.get(此。_listDataHeader.get(groupPosition))
.size();
}
@凌驾
公共对象getGroup(int-groupPosition){
返回此。\u listDataHeader.get(groupPosition);
}
@凌驾
public int getGroupCount(){
返回此值。_listDataHeader.size();
}
@凌驾
公共长getGroupId(int-groupPosition){
返回组位置
@Override
public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
if(listAdapter.getChildrenCount(groupPosition) == 0){
// TODO Auto-generated method stub
Intent intent=new Intent(ExpandableListActivity.this,MainActivity.class);
startActivity(intent);
}
return false;
}
@Override
public int getChildrenCount(int groupPosition) {
child_position=this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
// group_position=groupPosition; <<<change to below>>>
ExpandableListActivity.this.groupPosition=groupPosition;
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
}