Android 多层级列表实现

方法一：

Element.java ：

package com.chy.ydy.tools.treeutil;
/*** TreeView 元素* */
public class Element {/** 文字内容 */private String contentText;/** 在tree中的层级 */private int level;/** 元素的id */private int id;/** 父元素的id */private int parendId;/** 是否有子元素 */private boolean hasChildren;/** item是否展开 */private boolean isExpanded;/** 表示该节点没有父元素，也就是level为0的节点 */public static final int NO_PARENT = -1;/** 表示该元素位于最顶层的层级 */public static final int TOP_LEVEL = 0;/** 构造函数 */public Element(String contentText, int level, int id, int parendId, boolean hasChildren, boolean isExpanded){super();this.contentText = contentText;this.level = level;this.id = id;this.parendId = parendId;this.hasChildren = hasChildren;this.isExpanded = isExpanded;}public String getContentText() {return contentText;}public void setContentText(String contentText) {this.contentText = contentText;}public int getLevel() {return level;}public void setLevel(int level) {this.level = level;}public int getId() {return id;}public void setId(int id) {this.id = id;}public int getParendId() {return parendId;}public void setParendId(int parendId) {this.parendId = parendId;}public boolean isHasChildren() {return hasChildren;}public void setHasChildren(boolean hasChildren) {this.hasChildren = hasChildren;}public boolean isExpanded() {return isExpanded;}public void setExpanded(boolean expanded) {isExpanded = expanded;}
}

TreeViewAdapter.java:

package com.chy.ydy.tools.treeutil;import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import com.chy.ydy.R;import java.util.ArrayList;
/*** TreeView 适配器* */
public class TreeViewAdapter extends BaseAdapter {/** 元素数据源 */private ArrayList<Element> elementsData;/** 树中元素 */private ArrayList<Element> elements;/** LayoutInflater */private Activity activity;/** item的行首缩进基数 */private int indentionBase;/** 构造函数 */public TreeViewAdapter(ArrayList<Element> elements, ArrayList<Element> elementsData, Activity activity) {this.elements = elements;this.elementsData = elementsData;this.activity = activity;indentionBase = 50;}/** 树中元素列表 */public ArrayList<Element> getElements() {return elements;}/** 元素数据源列表 */public ArrayList<Element> getElementsData() {return elementsData;}@Overridepublic int getCount() {return elements.size();}@Overridepublic Object getItem(int position) {return elements.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View contentView, ViewGroup parent) {ViewHodler hodler = null;if (contentView == null){hodler = new ViewHodler();LayoutInflater inflater = LayoutInflater.from(activity);// 布局contentView = inflater.inflate(R.layout.treeview_item,null);hodler.prefixImg = contentView.findViewById(R.id.prefixImg);hodler.contentText = contentView.findViewById(R.id.contentText);contentView.setTag(hodler);}else {hodler = (ViewHodler) contentView.getTag();}Element element =elements.get(position); // 获取数据int level = element.getLevel();// 获取该数据层级// 设置前缀图片位置hodler.prefixImg.setPadding(indentionBase * (level+1),hodler.prefixImg.getPaddingTop(),hodler.prefixImg.getPaddingRight(),hodler.prefixImg.getPaddingBottom());// 设置内容hodler.contentText.setText(element.getContentText());// 判断是否有子集并且是否展开if (element.isHasChildren() && !element.isExpanded()){// 设置关闭item前缀图片// 设置图片为关闭hodler.prefixImg.setImageResource(R.mipmap.ic_cancle);//这里要主动设置一下icon可见，因为convertView有可能是重用了"设置了不可见"的view。hodler.prefixImg.setVisibility(View.VISIBLE);} else if (element.isHasChildren() && element.isExpanded()) {// 设置展开item前缀图片// 设置图片为打开hodler.prefixImg.setImageResource(R.mipmap.ic_down);//这里要主动设置一下icon可见，因为convertView有可能是重用了"设置了不可见"的view。hodler.prefixImg.setVisibility(View.VISIBLE);} else if (!element.isHasChildren()) {// 设置没有子集的item前缀图片// 设置图片为打开hodler.prefixImg.setImageResource(R.mipmap.ic_cltd);// 设置了不可见的view。//hodler.prefixImg.setVisibility(View.VISIBLE);// 设置了可见的view。hodler.prefixImg.setVisibility(View.VISIBLE);}return contentView;}/*** 优化Holder* */static class ViewHodler{private ImageView prefixImg;// 前缀图片private TextView contentText;// 内容//private ImageView suffixImg;// 后缀图片}}

TreeViewItemClickListener.java:

package com.chy.ydy.tools.treeutil;import android.view.View;
import android.widget.AdapterView;
import java.util.ArrayList;/*** TreeView item 点击事件* */
public class TreeViewItemClickListener implements AdapterView.OnItemClickListener {/** 没有子集item点击接口 */protected TreeViewNoHasChildrenItemClick noHasChildrenItemClick;/** adapter */private TreeViewAdapter treeViewAdapter;/** 构造函数 */public TreeViewItemClickListener(TreeViewAdapter treeViewAdapter){this.treeViewAdapter = treeViewAdapter;}@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position, long id) {//点击的item代表的元素Element element = (Element) treeViewAdapter.getItem(position);//树中的元素ArrayList<Element> elements = treeViewAdapter.getElements();//元素的数据源ArrayList<Element> elementsData = treeViewAdapter.getElementsData();/** 点击没有子项的item */if (!element.isHasChildren()){// 设置没有子集item点击接口参数noHasChildrenItemClick.onTreeItemClick(position,element);return;}/** 点击有子项的item */if (element.isExpanded()){// 收缩element.setExpanded(false);// 删除节点内部对应子节点数据，包括子节点的字节点...ArrayList<Element> elementsToDel = new ArrayList<Element>();for (int i = position+1;i < elements.size(); i++){if (element.getLevel() >= elements.get(i).getLevel())break;elementsToDel.add(elements.get(i));}elements.removeAll(elementsToDel);treeViewAdapter.notifyDataSetChanged();}else {// 展开element.setExpanded(true);//从数据源中提取子节点数据添加进树，注意这里只是添加了下一级子节点，为了简化逻辑int i = 1;//注意这里的计数器放在for外面才能保证计数有效for (Element e : elementsData){if (e.getParendId() == element.getId()){e.setExpanded(false);elements.add(position+i,e);i++;}}treeViewAdapter.notifyDataSetChanged();}}/*** 设置点击事件* */public void setNoHasChildrenItemClick(TreeViewNoHasChildrenItemClick noHasChildrenItemClick) {this.noHasChildrenItemClick = noHasChildrenItemClick;}/*** 没有子类item点击事件接口* */public interface TreeViewNoHasChildrenItemClick {void onTreeItemClick(int position, Element element);}}

实现代码：

package com.example.javademo;import androidx.appcompat.app.AppCompatActivity;import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.ListView;
import com.example.javademo.tree.Element;
import com.example.javademo.tree.TreeViewAdapter;
import com.example.javademo.tree.TreeViewItemClickListener;import java.util.ArrayList;public class MainActivity extends AppCompatActivity {/** 树中的元素集合 */private ArrayList<Element> elements;/** 数据源元素集合 */private ArrayList<Element> elementsData;private ListView treeView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);init();treeView = findViewById(R.id.treeView);TreeViewAdapter treeViewAdapter = new TreeViewAdapter(elements,elementsData,inflater);TreeViewItemClickListener treeViewItemClickListener = new TreeViewItemClickListener(treeViewAdapter);// 回调函数-没有子集item点击事件treeViewItemClickListener.setNoHasChildrenItemClick(new TreeViewItemClickListener.TreeViewNoHasChildrenItemClick() {@Overridepublic void onTreeItemClick(int position, Element element) {System.out.println("element"+element.getContentText());}});treeView.setAdapter(treeViewAdapter);treeView.setOnItemClickListener(treeViewItemClickListener);}private void init(){elements = new ArrayList<Element>();elementsData = new ArrayList<Element>();//添加节点 -- 节点名称，节点level，节点id，父节点id，是否有子节点，是否展开//添加最外层节点Element n1 = new Element("朝阳区", Element.TOP_LEVEL, 0, Element.NO_PARENT, true, false);// 添加第一层节点Element n11 = new Element("地铁2号线建设广场站", Element.TOP_LEVEL+1,11,n1.getId(),true,false);// 添加第一层节点Element n12 = new Element("地铁5号线湖西路站", Element.TOP_LEVEL+1,12,n1.getId(),true,false);// 添加第一层节点Element n13 = new Element("宽平大路北旧城改造地块", Element.TOP_LEVEL+1,13,n1.getId(),true,false);//添加最外层节点Element n2 = new Element("绿园区", Element.TOP_LEVEL, 1, Element.NO_PARENT, true, false);// 添加第一层节点Element n22 = new Element("合心镇加油站", Element.TOP_LEVEL+1,22,n2.getId(),true,false);// 添加第一层节点Element n23 = new Element("皓月5号地", Element.TOP_LEVEL+1,23,n2.getId(),true,false);// 添加第一层节点Element n24 = new Element("西安桥", Element.TOP_LEVEL+1,24,n2.getId(),true,false);//添加初始树元素elements.add(n1);elements.add(n2);// 创建数据源elementsData.add(n11);elementsData.add(n12);elementsData.add(n13);elementsData.add(n22);elementsData.add(n23);elementsData.add(n24);}}