Question

我试图为包含我的复选框的列表创建BaseAdapter。问题是，当我尝试获取每个行项的标记时，它返回null。

适配器：

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;

public class TaskListAdapter extends BaseAdapter {
    Context context;
    List<Patient> rowItems;

    public TaskListAdapter(Context context, List<Patient> items) {
        super();
        this.context = context;
        this.rowItems = items;
    }

    /*private view holder class*/
    private class ViewHolder {
        TextView txtTitle;
        TextView txtDesc;
        CheckBox checkbox;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;

        LayoutInflater mInflater = (LayoutInflater)
            context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.row, parent, false);
            holder = new ViewHolder();
            holder.txtTitle = (TextView) convertView.findViewById(R.id.firstLine);
            holder.txtDesc = (TextView) convertView.findViewById(R.id.secondLine);
            holder.checkbox = (CheckBox)convertView.findViewById(R.id.checkbox);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        Patient rowItem = (Patient) getItem(position);

        holder.txtDesc.setText(rowItem.getName());
        holder.txtTitle.setText(rowItem.getAddress());
        holder.checkbox.setChecked(rowItem.isSelected());

        holder.checkbox.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                CheckBox checkbox = (CheckBox)v.findViewById(R.id.checkbox);
                Patient rowItem = (Patient) checkbox.getTag();
                         // rowItem is null now for some reason
                rowItem.setSelected(checkbox.isChecked());
            }
        });

        return convertView;
    }

    @Override
    public int getCount() {
        return rowItems.size();
    }

    @Override
    public Object getItem(int position) {
        return rowItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return rowItems.indexOf(getItem(position));
    }
}

模型类：

public class Patient {
    private String name;
    private String address;
    private boolean checked;

    public Patient(String name, String address, boolean checked) {
        super();
        this.name = name;
        this.address = address;
        this.checked = checked;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public boolean isSelected() {
        return checked;
    }
    public void setSelected(boolean checked) {
        this.checked = checked;
    }

}

我试图获取每一行的标记，以便在滚动视图时保存复选框状态。感谢。

Answer 1

您实际上从未为CheckBox视图设置标记（R.id.checkbox）。至少没有您共享的代码中的位置。因此OnClickListener中的rowItem只能为null。修复：

holder.checkbox.setTag(rowItem);

您可以只引用下面显示的rowItem，而不是将Patient设置为CheckBox的标记：

final Patient rowItem = (Patient) getItem(position);

holder.txtDesc.setText(rowItem.getName());
holder.txtTitle.setText(rowItem.getAddress());
holder.checkbox.setChecked(rowItem.isSelected());

holder.checkbox.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        CheckBox checkbox = (CheckBox)v.findViewById(R.id.checkbox);
        rowItem.setSelected(checkbox.isChecked());
    }
});

Android BaseAdapter：getTag（）返回null

1 个答案: