Question

我的ExpendableListView Adapter类中有2个数组，它为我的组和子标头提供虚拟数据。第一个数组是常规数组，第二个数组是2D数组。

public class ExpandableListViewAdapter extends BaseExpandableListAdapter {

String[] groupNames = {
        "Fall 2016", "Winter 2017",
        "Fall 2017", "Winter 2018",
        "Fall 2018", "Winter 2019",
        "Fall 2019", "Winter 2020"
};

String[][] childNames = {
        {"JAVA101", "MATH101", "CHEM101"},{"JAVA201", "MATH201", "CHEM201"},
        {"JAVA301", "MATH301", "CHEM301"},{"JAVA401", "MATH401", "CHEM401"},
        {"JAVA501", "MATH501", "CHEM501"},{"JAVA601", "MATH601", "CHEM601"},
        {"JAVA701", "MATH701", "CHEM701"},{"JAVA801", "MATH801", "CHEM801"}
};

根据需要，我已经实现了所有必要的方法并将它们附加到我的数组中。

Context context;

    public ExpandableListViewAdapter(Context context){
        this.context = context;
    }

    @Override
    public int getGroupCount() {
        return groupNames.length;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return childNames[groupPosition].length;
    }

    @Override
    public Object getGroup(int groupPosition) {
        return groupNames[groupPosition];
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return childNames[groupPosition][childPosition];
    }

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

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View view, ViewGroup parent) {
        TextView textView = new TextView(context);
        textView.setText(groupNames[groupPosition]);
        textView.setPadding(100,0,0,0);
        textView.setTextColor(Color.BLACK);
        textView.setTextSize(20);

        return textView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View view, ViewGroup parent) {
        final TextView textView = new TextView(context);
        textView.setText("Java" + groupNames[childPosition] + "01");
        textView.setPadding(100,0,0,0);
        textView.setTextColor(Color.BLACK);
        textView.setTextSize(10);

        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context, textView.getText().toString(), Toast.LENGTH_SHORT).show();
            }
        });

        return textView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }

一切正常。我想要做的是通过FAB点击动态地将数据添加到我的ExpandableListView。我对我是否需要在我的适配器中实现我的FAB按钮的onClick()功能感到非常好奇。

Answer 1

首先动态添加数据使用ArrayList

无需实现onclick（）;在适配器中添加活动onclick
然后使用notifyDatasetchanged（）;在适配器上，这将解决问题

Answer 2

无法修改数组的大小。如果你想要一个更大的数组，你必须实例化一个新数组。更好的解决方案是使用可以根据需要增长的ArrayList。

因此，在适配器中创建一个方法，将新项目添加到现有列表中。在该方法中，将新项添加到ArrayList并调用.notifyDataSetChanged()。

将groupNames替换为

List<String> places = Arrays.asList("Fall 2016", "Winter 2017", "Fall 2017", "Winter 2018", "Fall 2018", "Winter 2019", "Fall 2019", "Winter 2020");

对于childNames，你必须这样做

List<String[]> childNames = Arrays.asList(new String[]{"JAVA101", "MATH101", "CHEM101"}, new String[]{ "JAVA201", "MATH201", "CHEM201" } etc...);

OR

List<String[]> childNames = new ArrayList<String[]>(); childNames.add(new String[]{"JAVA101", "MATH101", "CHEM101"}); //etc...

你还必须更改你的适配器以使用ArrayLists而不是Arrays，我希望你明白这个想法

如何动态地向数组添加数据

2 个答案: