多级树形菜单的实现
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在Android里要实现树形菜单，都是用ExpandableList(也有高手自己继承ListView或者LinearLayout来做)，但是ExpandableList一般只能实现2级树形菜单......本文也依然使用ExpandableList，但是要实现的是3级树形菜单。
当用BaseExpandableListAdapter来实现二级树形菜单时，父项(getGroupView())和子项(getChildView())都是使用TextView。当要实现三级树形菜单时，子项(getChildView())就必须使用ExpandableList了.......另外还要定义结构体来方便调用三级树形的数据，二级树形菜单可以用如下：
三级树形菜单可以用如下，子项是二级树形菜单的结构体：
实现三级树形菜单有两点要注意的：
1、第二级也是个树形菜单，因此必须在第二级项目展开/回收时设置足够的空间来完全显示二级树形菜单；
2、在实现三级树形菜单时，发现菜单的方法都是用不了(如OnChildClickListener、OnGroupClickListener等)，因此要获得选中的数据就必须在外部定义好回调函数，然后在第二级生成二级树形菜单时回调这个外部函数。
PS：本文在解决No.2关键点的时候，只能取得第三级选中的序号.....而第一，第二级依然无法获取其序号。
main.xml源码如下：
testExpandableList.java是主类，调用其他工具类，源码如下：
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同学", "xxxxx女人"};
public String[][] child= {
{ "A君", "B君", "C君", "D君" },
{ "同学甲", "同学乙", "同学丙"},
{ "御姐", "萝莉" }
};
public String[] parent = { "xxxx好友", "xxxx同学"};
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练习----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
/**
* 三级树形菜单的事件不再可用，本函数由三级树形菜单的子项（二级菜单）进行回调
*/
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是实现二级树形菜单的工具类，源码如下：
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;//每项的高度
public static final int PaddingLeft=36;//每项的高度
private int myPaddingLeft=0;//如果是由SuperTreeView调用，则作为子项需要往右移
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是实现三级树形菜单的工具类，会用到TreeViewAdapter.java，源码如下：
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;
//二级树形菜单的结构体
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;
}
/**
* 三层树结构中的第二层是一个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
/**
* 三级树结构中的首层是TextView,用于作为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;
}
}
总结，使用ExpandableList实现三级树形菜单时有些bug不好解决，而且定义三维数组的时候也要倍加小心......所以尽量把数据化简来使用二级树形菜单。
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