标签:des android style blog http io ar os sp
上篇文章写了一下ExpandableListView,就是两层结构的点击,Android中没有三层结构的组件,这个时候需要自己去扩展一下,可以扩展ExpandableListView,也可以选择扩展ListView。为了是实现这个效果,也是在搜了很多文章(中国的文章你懂的),有个哥们在GitHub开源了项目,奈何封装的太多,看的头晕目眩。看到有人扩展ListView的更符合自己的想法,因为做服务器端的时候也是先加载顶层元素,然后控制点击事件加载父级下面的子元素,有这个理解就可以去是实现一颗所谓的N级结构,开始正题吧:
新建一个activity_tree.xml布局文件,里面放一个ListView即可:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.googletree.TreeActivity" > <ListView android:id="@+id/tree_list" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout>
新建一个tree_item布局文件:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > <ImageView android:id="@+id/homeImg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_alignParentLeft="true"/> <TextView android:id="@+id/treeText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toRightOf="@id/homeImg"/> </RelativeLayout>
需要展示一个树状结构的数据,先定义一个TreeNode类,存放数据:
public class TreeNode { /** 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; public TreeNode(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 boolean isExpanded() { return isExpanded; } public void setExpanded(boolean isExpanded) { 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; } }
为了填充视图的中ListView,需要自定义TreeViewAdapter:
public class TreeViewAdapter extends BaseAdapter { /** 所有的数据集合 */ private ArrayList<TreeNode> allNodes; /** 顶层元素结合*/ private ArrayList<TreeNode> topNodes; /** LayoutInflater */ private LayoutInflater inflater; /** item的行首缩进基数 */ private int indentionBase; public TreeViewAdapter(ArrayList<TreeNode> topNodes, ArrayList<TreeNode> allNodes, LayoutInflater inflater) { this.topNodes = topNodes; this.allNodes = allNodes; this.inflater = inflater; indentionBase =20; } public ArrayList<TreeNode> getTopNodes() { return topNodes; } public ArrayList<TreeNode> getAllNodes() { return allNodes; } @Override public int getCount() { return topNodes.size(); } @Override public Object getItem(int position) { return topNodes.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; if (convertView == null) { holder = new ViewHolder(); convertView = inflater.inflate(R.layout.tree_item, null); holder.homeImg = (ImageView) convertView.findViewById(R.id.homeImg); holder.treeText = (TextView) convertView.findViewById(R.id.treeText); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } TreeNode element = topNodes.get(position); int level =element.getLevel(); holder.homeImg.setPadding( indentionBase * (level + 1), holder.homeImg.getPaddingTop(), holder.homeImg.getPaddingRight(), holder.homeImg.getPaddingBottom()); holder.treeText.setText(element.getContentText()); if (element.isHasChildren() && !element.isExpanded()) { holder.homeImg.setImageResource(R.drawable.open); //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,下同。 holder.homeImg.setVisibility(View.VISIBLE); } else if (element.isHasChildren() && element.isExpanded()) { holder.homeImg.setImageResource(R.drawable.open); holder.homeImg.setVisibility(View.VISIBLE); } else if (!element.isHasChildren()) { holder.homeImg.setImageResource(R.drawable.open); holder.homeImg.setVisibility(View.VISIBLE); } return convertView; } static class ViewHolder{ ImageView homeImg; TextView treeText; } }
在Activity中的调用:
public class TreeActivity extends Activity { /** 树中的顶层元素集合 */ private ArrayList<TreeNode> topNodes; /** 所有的元素集合 */ private ArrayList<TreeNode> allNodes; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_tree); LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); init(); ListView treeview = (ListView) findViewById(R.id.tree_list); TreeViewAdapter treeViewAdapter = new TreeViewAdapter(topNodes, allNodes, inflater); TreeViewItemClickListener treeViewItemClickListener = new TreeViewItemClickListener(treeViewAdapter); treeview.setAdapter(treeViewAdapter); treeview.setOnItemClickListener(treeViewItemClickListener); } private void init() { topNodes = new ArrayList<TreeNode>(); allNodes = new ArrayList<TreeNode>(); //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 TreeNode node1= new TreeNode("北京市", TreeNode.TOP_LEVEL, 0, TreeNode.NO_PARENT, true, false); //添加第一层节点 TreeNode node2= new TreeNode("海淀区", TreeNode.TOP_LEVEL + 1, 1, node1.getId(), true, false); //添加第二层节点 TreeNode node3= new TreeNode("西二旗", TreeNode.TOP_LEVEL + 2, 2, node2.getId(), true, false); //添加第三层节点 // TreeNode node7= new TreeNode("辉煌国际", TreeNode.TOP_LEVEL + 3, 6, node3.getId(), false, false); //添加第一层节点 TreeNode node4= new TreeNode("河南省", TreeNode.TOP_LEVEL , 3, TreeNode.NO_PARENT, true, false); //添加第二层节点 TreeNode node5= new TreeNode("郑州市", TreeNode.TOP_LEVEL + 1, 4, node4.getId(), true, false); //添加第三层节点 TreeNode node6= new TreeNode("金水区", TreeNode.TOP_LEVEL + 2, 5, node5.getId(), false, false); //添加初始树元素 topNodes.add(node1); topNodes.add(node4); //创建数据源 allNodes.add(node1); allNodes.add(node2); allNodes.add(node3); allNodes.add(node4); allNodes.add(node5); allNodes.add(node6); // allNodes.add(node7); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.tree, menu); return true; } }
由于每次都是加载一层节点,需要自己控制点击事件,自定义一个TreeViewItemClickListener:
public class TreeViewItemClickListener implements OnItemClickListener { /** 定义的适配器 */ private TreeViewAdapter treeViewAdapter; public TreeViewItemClickListener(TreeViewAdapter treeViewAdapter) { this.treeViewAdapter = treeViewAdapter; } @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { //点击的item代表的元素 TreeNode treeNode = (TreeNode) treeViewAdapter.getItem(position); //树中顶层的元素 ArrayList<TreeNode> topNodes = treeViewAdapter.getTopNodes(); //元素的数据源 ArrayList<TreeNode> allNodes = treeViewAdapter.getAllNodes(); //点击没有子项的item直接返回 if (!treeNode.isHasChildren()) { return; } if (treeNode.isExpanded()) { treeNode.setExpanded(false); //删除节点内部对应子节点数据,包括子节点的子节点... ArrayList<TreeNode> elementsToDel = new ArrayList<TreeNode>(); for (int i = position + 1; i < topNodes.size(); i++) { if (treeNode.getLevel() >= topNodes.get(i).getLevel()) break; elementsToDel.add(topNodes.get(i)); } topNodes.removeAll(elementsToDel); treeViewAdapter.notifyDataSetChanged(); } else { treeNode.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 (TreeNode e : allNodes) { if (e.getParendId() == treeNode.getId()) { e.setExpanded(false); topNodes.add(position + i, e); i ++; } } treeViewAdapter.notifyDataSetChanged(); } } }
代码搞定,看初始效果吧:
全部展开:
这个时候把treeActivity中那个node7注释取消,也就是加了第三层节点的效果:
TreeNode node7= new TreeNode("辉煌国际", TreeNode.TOP_LEVEL + 3, 6, node3.getId(), false, false);
效果如下:
好了,无限极结构实现了,周四愉快~北京早安~
标签:des android style blog http io ar os sp
原文地址:http://www.cnblogs.com/xiaofeixiang/p/4109704.html