java如何将ListAdapter中创建的视图添加到数组

Question

假设我有一个如下所示的适配器：

public class CalculateListingsLVAdapter extends ArrayAdapter {
    private String[] Vars;
    private String[] VarDescriptions;
    private Activity context;
    public CalculateListingsLVAdapter(Activity context, String[] Vars, String[] Vardescs) {
        super(context, R.layout.make_calculation_lv, Vars);
        this.context = context;
        this.Vars = Vars;
        this.VarDescriptions= Vardescs;

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row=convertView;

        LayoutInflater inflater = context.getLayoutInflater();
        if(convertView==null)
            row = inflater.inflate(R.layout.make_calculation_lv, null, true);
        TextView titleTV = (TextView) row.findViewById(R.id.VarTitle);
        EditText userINP = row.findViewById(R.id.VarInput);
        if (!VarDescriptions[position].equals("")) {
            String g = Vars[position] + " - " + VarDescriptions[position];
            titleTV.setText(g);
        } else {
            titleTV.setText(Vars[position]);
        }
        userINP.setTag(Vars[position]);
        return row;
    }


}

我希望能够从编辑文本中获取输入。很明显，像这样的事情是行不通的：

        ListView calcLV = findViewById(R.id.VariablesLV);
        EditText et;
        View r;
        String curform = formula;

        for (int i = 0; i < calcLV.getCount(); i++) {
            r = calcLV.getChildAt(i);
            et =  r.findViewById(R.id.VarInput);
            String l = (String) et.getTag();
            System.out.println(l);
            String val = et.getText().toString();
            curform = curform.replace(l,val);
        }

因为ListView不会始终显示所有项目

因此，我尝试将以下代码添加到适配器：

public ArrayList<EditText> editTxts = new ArrayList<>();

然后将每个userINP editText附加到ArrayList中，以便以后访问。不幸的是，这导致了null对象引用错误，该错误表明我无法将userINP添加到数组中

如何最好地解决这个问题

Answer 1

我刚想出来：

在ArrayAdapter类中，创建一个ArrayList以在编辑编辑文本时存储editText值，如下所示：

public class CalculateListingsLVAdapter extends ArrayAdapter {
    private String[] Vars;
    private String[] VarDescriptions;
    private Activity context;
    public ArrayList<String> textValues = new ArrayList<>();
    public CalculateListingsLVAdapter(Activity context, String[] Vars, String[] Vardescs) {
        super(context, R.layout.make_calculation_lv, Vars);
        this.context = context;
        this.Vars = Vars;
        this.VarDescriptions= Vardescs;

    }


    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        View row=convertView;
        System.out.println(position);
        LayoutInflater inflater = context.getLayoutInflater();
        if(convertView==null)
            row = inflater.inflate(R.layout.make_calculation_lv, null, true);
        TextView titleTV = (TextView) row.findViewById(R.id.VarTitle);
        final EditText userINP = row.findViewById(R.id.VarInput);
        userINP.addTextChangedListener(new TextWatcher()
        {
            @Override
            public void afterTextChanged(Editable mEdit)
            {
                String g = Vars[position] + "_____" + mEdit.toString();
                for (int i = 0; i < textValues.size(); i++){
                    if (textValues.get(i).contains(Vars[position])){
                        textValues.remove(i);
                    }
                }
                textValues.add(g);
            }

            public void beforeTextChanged(CharSequence s, int start, int count, int after){}

            public void onTextChanged(CharSequence s, int start, int before, int count){}
        });
        if (!VarDescriptions[position].equals("")) {
            String g = Vars[position] + " - " + VarDescriptions[position];
            titleTV.setText(g);
        } else {
            titleTV.setText(Vars[position]);
        }

        return row;
    }


}

然后，在MainActivity中，可以从ArrayList中进行绘制，并使用正则表达式获取变量和值