Question

您好我正在使用带有复选框的自定义列表视图编写程序。我的目的是在单击按钮（添加）时启动新活动，新活动将显示列表视图中的选定值。我在尝试添加值时出现错误

错误发生线是

selectedItems.add（adapter.getItem（位置））;

如果我对此行发表评论，那么我可以选中该框但是当我点击“添加”按钮时它会显示错误。

这是我的完整代码。

我的主要活动

HomePage.java

public class HomePage extends Activity {
private ListView listView1;
ListAdapter adapter;
Button btn;
SparseBooleanArray checkedValue;
ArrayList<List> selectedItems;
String name;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home_page);

    List device_data[] = new List[]
                {
        new List(R.drawable.ic_pic , "Actvity1"),
        new List(R.drawable.ic_pic, "Actvity2"),
        new List(R.drawable.ic_pic, "Actvity3"),
        new List(R.drawable.ic_pic, "Actvity4"),
        new List(R.drawable.ic_pic, "Actvity5")

                     };


    ListAdapter adapter = new ListAdapter(this,  R.layout.list_viewrow, device_data);

        listView1 = (ListView)findViewById(R.id.listView1);

       View header = (View)getLayoutInflater().inflate(R.layout.listview_header, null);
       listView1.addHeaderView(header);

       listView1.setAdapter(adapter);


       Log.i("check box status", ""+ListAdapter.ListHolder.class);

             btn= (Button)findViewById(R.id.add);
             btn.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {


                        String[] outputStrArr = new String[selectedItems.size()];
                        checkedValue= listView1.getCheckedItemPositions();
                        for (int i = 0; i < selectedItems.size(); i++) {
                            outputStrArr[i] = selectedItems.get(i).toString();
                        }
                        Intent intent = new Intent(getApplicationContext(),
                               CheckedValues.class);
                         Bundle b = new Bundle();
                         b.putStringArray("selectedItems", outputStrArr);

                         // Add the bundle to the intent.
                         intent.putExtras(b);
                        startActivity(intent);
                    }
                });


      }
private class ListAdapter extends ArrayAdapter<List> {
    Context context; 
    int layoutResourceId;   
    boolean checkvalue;
    List data[] = null;

    public ListAdapter(Context context, int layoutResourceId, List[] data) {
        super(context, layoutResourceId, data);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.data = data;
    }

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

        if(row == null)
        {
            LayoutInflater inflater = ((Activity)context).getLayoutInflater();
            row = inflater.inflate(layoutResourceId, parent, false);

            holder = new ListHolder();
            holder.imgIcon = (ImageView)row.findViewById(R.id.imgIcon);
            holder.txtTitle = (TextView)row.findViewById(R.id.txtTitle);
            holder.checkbox=(CheckBox) row.findViewById(R.id.check);


           holder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {


                         selectedItems.add(adapter.getItem(position));



                }


              });

            row.setTag(holder);
        }
        else
        {
            holder = (ListHolder)row.getTag();
        }

        List list = data[position];
        holder.txtTitle.setText(list.title);
        holder.imgIcon.setImageResource(list.icon);

        return row;
    }


    class ListHolder
    {
        ImageView imgIcon;
        TextView txtTitle;
        CheckBox checkbox;
    }

}
}

和我的第二项活动

CheckedValues.java

public class CheckedValues extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_checked_values);

    Bundle b = getIntent().getExtras();
    String[] resultArr = b.getStringArray("selectedItems");
    ListView lv = (ListView) findViewById(R.id.outputList);

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, resultArr);
    lv.setAdapter(adapter);

}

}

提前感谢..

Answer 1

初始化“ArrayList”

ArrayList<List> selectedItems;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home_page);
selectedItems = new ArrayList<List>();
}

将自定义列表视图中的选中项添加到android中的数组列表中

1 个答案: