我有一个多级(3级,Root – > Parent – > Child)ExpandableListView包含也是ExpandableListViews的子级.
我没有填补它们的问题;但是,当我第一次显示Activity(onCreate)时,我需要在Parent级别中展开特定项.
我成功地扩展了Parent的相关Root项,但我似乎无法扩展Parent项.调用给定的侦听器,但结果不会反映在我的多级列表中.
我称之为扩展的活动：
public class Activity {
private int groupToExpand = 4, childToExpand = 3;
protected void onCreate(Bundle savedInstance) {
final ExpandableListView elv = (ExpandableListView) findViewById(R.id.elv);
if (arrayList!= null && !arrayList.isEmpty()) {
elv.setAdapter(new RootAdapter(this, arrayList);
// this selects the correct group, but doesn't expand the child.
elv.setSelectedChild(groupToExpand, childToExpand, true);
elv.expandGroup(groupToExpand); // this works.
}
}
}
我的Root适配器：
public class RootAdapter extends Baseexpandablelistadapter {
private List<Objects> arrayList;
private Context context;
private LayoutInflater inflater;
public RootAdapter(Context context, List<Objects> arrayList) {
this.context = context;
this.arrayList = arrayList;
this.inflater = LayoutInflater.from(context);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
final Objects parent = (Objects) getGroup(groupPosition);
return parent.arrayList.get(childPosition);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final Objects o = (Objects) getChild(groupPosition, childPosition);
CustomExpandableListView elv = (CustomExpandableListView) convertView;
ChildViewHolder holder;
if (elv == null) {
holder = new ChildViewHolder();
elv = new CustomExpandableListView(context);
elv.setGroupIndicator(null);
elv.setDivider(null);
elv.setCacheColorHint(Color.parseColor("#00000000"));
elv.setChildDivider(null);
elv.setChildindicator(null);
elv.setScrollingCacheEnabled(false);
elv.setAnimationCacheEnabled(false);
holder.cListView = elv;
elv.setTag(holder);
} else {
holder = (ChildViewHolder) elv.getTag();
}
final ParentAdapter adapter = new ParentAdapter(context, o);
holder.cListView.setAdapter(adapter);
return elv;
}
private static class ChildViewHolder {
CustomExpandableListView cListView;
}
@Override
public int getChildrenCount(int groupPosition) {
final Objects parent = (Objects) getGroup(groupPosition);
return parent.arrayList.size();
}
@Override
public Object getGroup(int groupPosition) {
return arrayList.get(groupPosition);
}
@Override
public int getGroupCount() {
return arrayList.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
View layout = convertView;
GroupViewHolder holder;
final Objects o = (Objects) getGroup(groupPosition);
if (layout == null) {
layout = inflater.inflate(R.layout.item_to_inflate, parent, false);
holder = new GroupViewHolder();
holder.title = (TextView) layout.findViewById(R.id.title);
holder.image = (ImageView) layout.findViewById(R.id.image);
layout.setTag(holder);
} else {
holder = (GroupViewHolder) layout.getTag();
}
holder.title.setText(o.title.trim());
return layout;
}
@Override
public boolean hasstableIds() {
return true;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
private static class GroupViewHolder {
TextView title;
ImageView image;
}
public class CustomExpandableListView extends ExpandableListView {
public CustomExpandableListView(Context context) {
super(context);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
heightMeasureSpec = MeasureSpec.makeMeasureSpec(2000, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
}
最后我的ParentAdapter：
public class ParentAdapter extends Baseexpandablelistadapter {
private Objects child;
private LayoutInflater inflater;
public ParentAdapter(Context context, Objects child) {
this.child = child;
this.inflater = LayoutInflater.from(context);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return child.arrayList.get(childPosition);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
View layout = convertView;
final Objects o = (Objects) getChild(0, childPosition);
ChildViewHolder holder;
if (layout == null) {
layout = inflater.inflate(R.layout.item_to_inflate, parent, false);
holder = new ChildViewHolder();
holder.title = (TextView) layout.findViewById(R.id.title);
layout.setTag(holder);
} else {
holder = (ChildViewHolder) layout.getTag();
}
holder.title.setText(o.title.trim());
return layout;
}
@Override
public int getChildrenCount(int groupPosition) {
return child.arrayList.size();
}
@Override
public Object getGroup(int groupPosition) {
return child;
}
@Override
public int getGroupCount() {
return 1;
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
View layout = convertView;
GroupViewHolder holder;
if (layout == null) {
layout = inflater.inflate(R.layout.item_to_inflate, parent, false);
holder = new GroupViewHolder();
holder.image = (ImageView) layout.findViewById(R.id.image);
holder.title = (TextView) layout.findViewById(R.id.title);
layout.setTag(holder);
} else {
holder = (GroupViewHolder) layout.getTag();
}
holder.title.setText(o.title.trim());
return layout;
}
@Override
public boolean hasstableIds() {
return true;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
private static class GroupViewHolder {
TextView title;
ImageView image;
}
private static class ChildViewHolder {
TextView title;
}
}
我无法在根ExpandableListView中扩展子列表;你知道在父级别扩展项目的任何正确方法吗？
我尝试了RootAdapter的getChildView：
if (groupToExpand == groupPosition && childToExpand == childPosition) {
elv.expandGroup(childToExpand);
}
然后在我改变的活动中：
if (arrayList!= null && !arrayList.isEmpty()) {
RootAdapter adapter = new RootAdapter(this, arrayList);
elv.setAdapter(adapter);
// this selects the correct group, but doesn't expand the child.
elv.setSelectedChild(groupToExpand, childToExpand, true);
elv.expandGroup(groupToExpand); // this works.
adapter.groupToExpand = groupToExpand;
adapter.childToExpand = childToExpand;
adapter.notifyDataSetChanged();
}
这会扩展父级别项目,但是,它会生成父项的重复项目.我该怎么做呢？这是正确的方法,但我的适配器坏了,因此生成重复的项目？
我只是找不到我在这里失踪的东西……
解决方法:
我最终使用stackoverflow中另一个帖子的多级ExpandableListView适配器.不幸的是我再也找不到链接所以我只是在这里发布我的代码.
ExpandableListView适配器的顶级.
RootAdapter.java：
public class RootAdapter extends Baseexpandablelistadapter {
private Object root;
private final LayoutInflater inflater;
public class Entry {
public final CustExpListview cls;
public final SecondLevelAdapter sadpt;
public Entry(CustExpListview cls, SecondLevelAdapter sadpt) {
this.cls = cls;
this.sadpt = sadpt;
}
}
public Entry[] lsfirst;
// you can change the constructor depending on which listeners you wan't to use.
public RootAdapter(Context context, Object root, ExpandableListView.OnGroupClickListener grpLst,
ExpandableListView.OnChildClickListener childLst, ExpandableListView.OnGroupExpandListener grpExpLst) {
this.root = root;
this.inflater = LayoutInflater.from(context);
lsfirst = new Entry[root.children.size()];
for (int i = 0; i < root.children.size(); i++) {
final CustExpListview celv = new CustExpListview(context);
SecondLevelAdapter adp = new SecondLevelAdapter(root.children.get(i));
celv.setAdapter(adp);
celv.setGroupIndicator(null);
celv.setonChildClickListener(childLst);
celv.setonGroupClickListener(grpLst);
celv.setonGroupExpandListener(grpExpLst);
lsfirst[i] = new Entry(celv, adp);
}
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
View convertView, ViewGroup parent) {
// second level list
return lsfirst[groupPosition].cls;
}
@Override
public int getChildrenCount(int groupPosition) {
return 1;
}
@Override
public Object getGroup(int groupPosition) {
return root.children.get(groupPosition);
}
@Override
public int getGroupCount() {
return root.children.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
ViewGroup parent) {
// first level
View layout = convertView;
GroupViewHolder holder;
final Object item = (Object) getGroup(groupPosition);
if (layout == null) {
layout = inflater.inflate(R.layout.item_root, parent, false);
holder = new GroupViewHolder();
holder.title = (TextView) layout.findViewById(R.id.itemRoottitle);
layout.setTag(holder);
} else {
holder = (GroupViewHolder) layout.getTag();
}
holder.title.setText(item.title.trim());
return layout;
}
private static class GroupViewHolder {
TextView title;
}
@Override
public boolean hasstableIds() {
return true;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
自定义ExpandableListView,有时不显示项目的解决方案.还有一种解决方法,即在销毁视图时调用IllegalArgumentException(主要是通过按后退按钮).
CustExpListview.java：
public class CustExpListview extends ExpandableListView {
public CustExpListview(Context context) {
super(context);
}
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// the value (2000) should not be fixed and be calculated
// as follows: cell_height x root_items_count x root_items_children_count
heightMeasureSpec = MeasureSpec.makeMeasureSpec(2000, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onDetachedFromWindow() {
try {
super.onDetachedFromWindow();
} catch (IllegalArgumentException e) {
// Todo: Workaround for http://code.google.com/p/android/issues/detail?id=22751
}
}
}
最后,代码到最后一级适配器.
public class SecondLevelAdapter extends Baseexpandablelistadapter {
public Object child;
public SecondLevelAdapter(Object child) {
this.child = child;
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return child.children.get(groupPosition).children.get(childPosition);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
// third level
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
View convertView, ViewGroup parent) {
View layout = convertView;
final Object item = (Object) getChild(groupPosition, childPosition);
ChildViewHolder holder;
if (layout == null) {
layout = inflater.inflate(R.layout.item_child, parent, false);
holder = new ChildViewHolder();
holder.title = (TextView) layout.findViewById(R.id.itemChildTitle);
layout.setTag(holder);
} else {
holder = (ChildViewHolder) layout.getTag();
}
holder.title.setText(item.title.trim());
return layout;
}
@Override
public int getChildrenCount(int groupPosition) {
return child.children.get(groupPosition).children.size();
}
@Override
public Object getGroup(int groupPosition) {
return child.children.get(groupPosition);
}
@Override
public int getGroupCount() {
return child.children.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
// Second level
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
ViewGroup parent) {
View layout = convertView;
ViewHolder holder;
final Object item = (Object) getGroup(groupPosition);
if (layout == null) {
layout = inflater.inflate(R.layout.item_parent, parent, false);
holder = new ViewHolder();
holder.title = (TextView) layout.findViewById(R.id.itemParentTitle);
layout.setTag(holder);
} else {
holder = (ViewHolder) layout.getTag();
}
holder.title.setText(item.title.trim());
return layout;
}
@Override
public void registerDataSetobserver(DataSetobserver observer) {
super.registerDataSetobserver(observer);
}
@Override
public void unregisterDataSetobserver(DataSetobserver observer) {
Log.d("SecondLevelAdapter", "Unregistering observer");
if (observer != null) {
super.unregisterDataSetobserver(observer);
}
}
@Override
public boolean hasstableIds() {
return true;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
private static class ViewHolder {
TextView title;
}
private static class ChildViewHolder {
TextView title;
}
}
我希望这有帮助！！！
更新
这是我如何调用上述适配器的示例.
主要活动：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final List<Object> objects = yourItems;
if (!objects.isEmpty()) {
final ExpandableListView elv = (ExpandableListView) findViewById(R.id.yourExpandableListView);
/* Item click listeners below */
// First level items in the ExpandableListView
elv.setonGroupClickListener(new ExpandableListView.OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView eListView, View view, int groupPosition,
long id) {
// Todo: whatever you need
return false /* or true depending on what you need */;
}
});
// Second level items in the ExpandableListView
ExpandableListView.OnGroupClickListener grpLst = new ExpandableListView.OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView eListView, View view, int groupPosition,
long id) {
// Todo: whatever you need
return false /* or true depending on what you need */;
}
};
// Third (and last) level items in the ExpandableListView
ExpandableListView.OnChildClickListener childLst = new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView eListView, View view, int groupPosition,
int childPosition, long id) {
// Todo: whatever you need
return false /* or true depending on what you need */;
}
};
ExpandableListView.OnGroupExpandListener grpExpLst = new ExpandableListView.OnGroupExpandListener() {
@Override
public void onGroupExpand(int groupPosition) {
/* this one is not required of course, you can delete it from the RootAdapter Constructor
* it is just an example as to how to implement Listeners on the second level items */
}
};
final RootAdapter adapter = new RootAdapter(this, objects, grpLst, childLst, grpExpLst);
elv.setAdapter(adapter);
}
}
这就是我的类Object的样子.
Object.java：
public class Object {
public String title; // use getters and setters instead
public List<Object> children; // same as above
public Object() {
children = new ArrayList<Object>();
}
}
