在Android里要實現(xiàn)樹形菜單，都是用ExpandableList(也有高手自己繼承ListView或者LinearLayout來做)，但是ExpandableList一般只能實現(xiàn)2級樹形菜單......本文也依然使用ExpandableList，但是要實現(xiàn)的是3級樹形菜單。
當用BaseExpandableListAdapter來實現(xiàn)二級樹形菜單時，父項(getGroupView())和子項(getChildView())都是使用TextView。當要實現(xiàn)三級樹形菜單時，子項(getChildView())就必須使用ExpandableList了.......另外還要定義結構體來方便調用三級樹形的數(shù)據(jù)，二級樹形菜單可以用如下：
三級樹形菜單可以用如下，子項是二級樹形菜單的結構體：
實現(xiàn)三級樹形菜單有兩點要注意的：
1、第二級也是個樹形菜單，因此必須在第二級項目展開/回收時設置足夠的空間來完全顯示二級樹形菜單；
2、在實現(xiàn)三級樹形菜單時，發(fā)現(xiàn)菜單的方法都是用不了(如OnChildClickListener、OnGroupClickListener等)，因此要獲得選中的數(shù)據(jù)就必須在外部定義好回調函數(shù)，然后在第二級生成二級樹形菜單時回調這個外部函數(shù)。
PS：本文在解決No.2關鍵點的時候，只能取得第三級選中的序號.....而第一，第二級依然無法獲取其序號。
main.xml源碼如下：
testExpandableList.java是主類，調用其他工具類，源碼如下：
package com.testExpandableList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.Toast;
public class testExpandableList extends Activity {
??? /** Called when the activity is first created. */
?ExpandableListView expandableList;
?TreeViewAdapter adapter;
?SuperTreeViewAdapter superAdapter;
?Button btnNormal,btnSuper;
??? // Sample data set.? children[i] contains the children (String[]) for groups[i].
??? public String[] groups = { "xxxx好友", "xxxx同學", "xxxxx女人"};
??? public String[][]? child= {
??????????? { "A君", "B君", "C君", "D君" },
??????????? { "同學甲", "同學乙", "同學丙"},
??????????? { "御姐", "蘿莉" }
??? };
???
??? public String[] parent = { "xxxx好友", "xxxx同學"};
??? public String[][][]? child_grandson= {
??? ??{{"A君"},
??? ???{"AA","AAA"}},
??? ??{{"B君"},
??? ???{"BBB","BBBB","BBBBB"}},
??? ??{{"C君"},
??? ???{"CCC","CCCC"}},
??? ??{{"D君"},
??? ???{"DDD","DDDD","DDDDD"}},
??? };
???
??? @Override
??? public void onCreate(Bundle savedInstanceState) {
??????? super.onCreate(savedInstanceState);
??????? setContentView(R.layout.main);
??????? this.setTitle("ExpandableListView練習----hellogv");
??????? btnNormal=(Button)this.findViewById(R.id.btnNormal);
??????? btnNormal.setOnClickListener(new ClickEvent());
??????? btnSuper=(Button)this.findViewById(R.id.btnSuper);
??????? btnSuper.setOnClickListener(new ClickEvent());
??????? adapter=new TreeViewAdapter(this,TreeViewAdapter.PaddingLeft>>1);
??????? superAdapter=new SuperTreeViewAdapter(this,stvClickEvent);
??????? expandableList=(ExpandableListView) testExpandableList.this.findViewById(R.id.ExpandableListView01);
??? }
???
??? class ClickEvent implements View.OnClickListener{
??@Override
??public void onClick(View v) {
???adapter.RemoveAll();
???adapter.notifyDataSetChanged();
???superAdapter.RemoveAll();
???superAdapter.notifyDataSetChanged();
???
???if(v==btnNormal)
???{
????????? List
?????@Override
?????public boolean onChildClick(ExpandableListView arg0, View arg1,
???????int parent, int children, long arg4) {
??????
??????String str="parent id:"+String.valueOf(parent)+",children id:"+String.valueOf(children);
??????Toast.makeText(testExpandableList.this, str, 300).show();
??????return false;
?????}
????????? });
???}
???else if(v==btnSuper){
????List
??? /**
???? * 三級樹形菜單的事件不再可用，本函數(shù)由三級樹形菜單的子項（二級菜單）進行回調
???? */
??? OnChildClickListener stvClickEvent=new OnChildClickListener(){
??@Override
??public boolean onChildClick(ExpandableListView parent,
????View v, int groupPosition, int childPosition,
????long id) {
???String str="parent id:"+String.valueOf(groupPosition)+",children id:"+String.valueOf(childPosition);
???Toast.makeText(testExpandableList.this, str, 300).show();
???
???return false;
??}
??? ?
??? };
}
TreeViewAdapter.java是實現(xiàn)二級樹形菜單的工具類，源碼如下：
?
package com.testExpandableList;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
public class TreeViewAdapter extends BaseExpandableListAdapter{
?public static final int ItemHeight=48;//每項的高度
?public static final int PaddingLeft=36;//每項的高度
?private int myPaddingLeft=0;//如果是由SuperTreeView調用，則作為子項需要往右移
?static public class TreeNode{
??Object parent;
??List
?public int getChildrenCount(int groupPosition) {
??return treeNodes.get(groupPosition).childs.size();
?}
?static public TextView getTextView(Context context) {
??AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
????ViewGroup.LayoutParams.FILL_PARENT, ItemHeight);
??TextView textView = new TextView(context);
??textView.setLayoutParams(lp);
??textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
??return textView;
?}
?public View getChildView(int groupPosition, int childPosition,
???boolean isLastChild, View convertView, ViewGroup parent) {
??TextView textView = getTextView(this.parentContext);
??textView.setText(getChild(groupPosition, childPosition).toString());
??textView.setPadding(myPaddingLeft+PaddingLeft, 0, 0, 0);
??return textView;
?}
?public View getGroupView(int groupPosition, boolean isExpanded,
???View convertView, ViewGroup parent) {
??TextView textView = getTextView(this.parentContext);
??textView.setText(getGroup(groupPosition).toString());
??textView.setPadding(myPaddingLeft+(PaddingLeft>>1), 0, 0, 0);
??return textView;
?}
?public long getChildId(int groupPosition, int childPosition) {
??return childPosition;
?}
?public Object getGroup(int groupPosition) {
??return treeNodes.get(groupPosition).parent;
?}
?public int getGroupCount() {
??return treeNodes.size();
?}
?public long getGroupId(int groupPosition) {
??return groupPosition;
?}
?public boolean isChildSelectable(int groupPosition, int childPosition) {
??return true;
?}
?public boolean hasStableIds() {
??return true;
?}
}
?
SuperTreeViewAdapter.java是實現(xiàn)三級樹形菜單的工具類，會用到TreeViewAdapter.java，源碼如下：
package com.testExpandableList;
import java.util.ArrayList;
import java.util.List;
import com.testExpandableList.TreeViewAdapter.TreeNode;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.TextView;
public class SuperTreeViewAdapter extends BaseExpandableListAdapter {
?static public class SuperTreeNode {
??Object parent;
??//二級樹形菜單的結構體
??List
?private List
?public List
?public void UpdateTreeNode(List
?public int getChildrenCount(int groupPosition) {
??return superTreeNodes.get(groupPosition).childs.size();
?}
?public ExpandableListView getExpandableListView() {
??AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
????ViewGroup.LayoutParams.FILL_PARENT, TreeViewAdapter.ItemHeight);
??ExpandableListView superTreeView = new ExpandableListView(parentContext);
??superTreeView.setLayoutParams(lp);
??return superTreeView;
?}
?/**
? * 三層樹結構中的第二層是一個ExpandableListView
? */?
?public View getChildView(int groupPosition, int childPosition,
???boolean isLastChild, View convertView, ViewGroup parent) {
??// 是
??final ExpandableListView treeView = getExpandableListView();
??final TreeViewAdapter treeViewAdapter = new TreeViewAdapter(this.parentContext,0);
??List
?/**
? * 三級樹結構中的首層是TextView,用于作為title
? */
?public View getGroupView(int groupPosition, boolean isExpanded,
???View convertView, ViewGroup parent) {
??TextView textView = TreeViewAdapter.getTextView(this.parentContext);
??textView.setText(getGroup(groupPosition).toString());
??textView.setPadding(TreeViewAdapter.PaddingLeft, 0, 0, 0);
??return textView;
?}
?public long getChildId(int groupPosition, int childPosition) {
??return childPosition;
?}
?public Object getGroup(int groupPosition) {
??return superTreeNodes.get(groupPosition).parent;
?}
?public int getGroupCount() {
??return superTreeNodes.size();
?}
?public long getGroupId(int groupPosition) {
??return groupPosition;
?}
?public boolean isChildSelectable(int groupPosition, int childPosition) {
??return true;
?}
?public boolean hasStableIds() {
??return true;
?}
}
總結，使用ExpandableList實現(xiàn)三級樹形菜單時有些bug不好解決，而且定義三維數(shù)組的時候也要倍加小心......所以盡量把數(shù)據(jù)化簡來使用二級樹形菜單。
?
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