Android TreeView如何實(shí)現(xiàn)

小樊
98
2024-07-10 15:14:39
欄目: 編程語言

Android TreeView可以通過自定義Adapter來實(shí)現(xiàn)。以下是一個(gè)簡單的示例代碼：

  1. 創(chuàng)建一個(gè)TreeItem類，用于表示樹節(jié)點(diǎn)的數(shù)據(jù)結(jié)構(gòu)：
public class TreeItem {
    private String name;
    private List<TreeItem> children;

    public TreeItem(String name) {
        this.name = name;
        this.children = new ArrayList<>();
    }

    public String getName() {
        return name;
    }

    public List<TreeItem> getChildren() {
        return children;
    }

    public void addChild(TreeItem child) {
        children.add(child);
    }
}
  1. 創(chuàng)建一個(gè)自定義的TreeAdapter類，繼承自BaseExpandableListAdapter，并實(shí)現(xiàn)相關(guān)方法：
public class TreeAdapter extends BaseExpandableListAdapter {
    private List<TreeItem> rootItems;

    public TreeAdapter(List<TreeItem> rootItems) {
        this.rootItems = rootItems;
    }

    @Override
    public int getGroupCount() {
        return rootItems.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return rootItems.get(groupPosition).getChildren().size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return rootItems.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return rootItems.get(groupPosition).getChildren().get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        // 實(shí)現(xiàn)group視圖的繪制
        return null;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        // 實(shí)現(xiàn)child視圖的繪制
        return null;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
}
  1. 在Activity或Fragment中使用TreeView和自定義的TreeAdapter：
TreeView treeView = findViewById(R.id.treeView);
List<TreeItem> rootItems = new ArrayList<>();
// 構(gòu)建樹結(jié)構(gòu)
TreeAdapter treeAdapter = new TreeAdapter(rootItems);
treeView.setAdapter(treeAdapter);

通過以上步驟，就可以實(shí)現(xiàn)一個(gè)簡單的Android TreeView。在TreeAdapter中，可以根據(jù)需要自定義group和child視圖的繪制邏輯，以實(shí)現(xiàn)不同的展示效果。

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