如何使箭头单击可扩展列表就像在Android的Youtube
问题描述:
我是一个Android开发人员,我只想扩大该图像中显示的列表,我点击它时,通过红色箭头指示它,列表应该像Youtube一样展开。如何使箭头单击可扩展列表就像在Android的Youtube
请建议我该怎么做。如何在箭头点击时展开此操作。如果有任何建议,请帮助我。
答
1,创建可扩展列表适配器类,如下所示扩展底座扩展列表适配器...
import java.util.HashMap;
import java.util.List;
import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
public class ExpandableListAdapter extends BaseExpandableListAdapter {
private Context context;
private List<String> expandableListTitle;
private HashMap<String, List<String>> expandableListDetail;
public ExpandableListAdapter(Context context, List<String> expandableListTitle,
HashMap<String, List<String>> expandableListDetail) {
this.context = context;
this.expandableListTitle = expandableListTitle;
this.expandableListDetail = expandableListDetail;
}
@Override
public Object getChild(int listPosition, int expandedListPosition) {
return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
.get(expandedListPosition);
}
@Override
public long getChildId(int listPosition, int expandedListPosition) {
return expandedListPosition;
}
@Override
public View getChildView(int listPosition, final int expandedListPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final String expandedListText = (String) getChild(listPosition, expandedListPosition);
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_item, null);
}
TextView expandedListTextView = (TextView) convertView
.findViewById(R.id.expandedListItem);
expandedListTextView.setText(expandedListText);
return convertView;
}
@Override
public int getChildrenCount(int listPosition) {
return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
.size();
}
@Override
public Object getGroup(int listPosition) {
return this.expandableListTitle.get(listPosition);
}
@Override
public int getGroupCount() {
return this.expandableListTitle.size();
}
@Override
public long getGroupId(int listPosition) {
return listPosition;
}
@Override
public View getGroupView(int listPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String listTitle = (String) getGroup(listPosition);
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.list_group, null);
}
TextView listTitleTextView = (TextView) convertView
.findViewById(R.id.listTitle);
listTitleTextView.setTypeface(null, Typeface.BOLD);
listTitleTextView.setText(listTitle);
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int listPosition, int expandedListPosition) {
return true;
}
}
-
创建您的列表视图。在布局xml中定义可展开列表视图
expandableListView = (ExpandableListView) findViewById(R.id.expandableListView); expandableListDetail = <ArrayList>; // Provide your array list here expandableListTitle = new ArrayList(<Title of your list goes here>); expandableListAdapter = new ExpandableListAdapter(this, expandableListTitle, expandableListDetail); expandableListView.setAdapter(expandableListAdapter); expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() { @Override public void onGroupExpand(int groupPosition) { Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Expanded.", Toast.LENGTH_SHORT).show(); } }); expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() { @Override public void onGroupCollapse(int groupPosition) { Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Collapsed.", Toast.LENGTH_SHORT).show(); } }); expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { Toast.makeText( getApplicationContext(), expandableListTitle.get(groupPosition) + " -> " + expandableListDetail.get( expandableListTitle.get(groupPosition)).get( childPosition), Toast.LENGTH_SHORT ) .show(); } });