在ListView的多节模式设置的限制 [英] Set Limit on ListView multiple section mode

问题描述

我有定义叫名字定义字符串的ArrayList，我添加到我的ListView对象如下：

我创建两个数组适配器和ListView对象数组适配器以及多种选择模式。这个伟大的工程，我可以滚动和选择多个对象。但问题是，我想向用户强行进入能够选择从ListView中只有4项。如何设置一个限制？

 适配器=新ArrayAdapter＆LT;串GT;（这一点，android.R.layout.simple_list_item_multiple_choice，姓名）;
nameList.setChoiceMode（ListView.CHOICE_MODE_MULTIPLE）;
nameList.setAdapter（适配器）;
 

解决方案

试试这个：

 公共类AccountListAdapter延伸BaseAdapter {@燮pressWarnings（未使用）
私人最终静态字符串变量= AccountListAdapter.class.getSimpleName（）;私人上下文的背景下;
私人列表＆LT;＆帐户GT; rowItems;私人INT selectedItemCounter = 0;私人最终诠释限制;公共AccountListAdapter（上下文的背景下，列表与LT;帐户＆GT;的项目，INT限制）{
    this.context =背景;
    this.rowItems =物品;
    this.limit =限制;
}公共查看getView（最终诠释的立场，观点convertView，父母的ViewGroup）{    LayoutInflater mInflater =（LayoutInflater）上下文
            .getSystemService（Activity.LAYOUT_INFLATER_SERVICE）;    决算rowItem =（账户）的getItem（位置）;    convertView = mInflater.inflate（R.layout.account_selection_item，NULL）;    TextView的电视=（TextView中）convertView.findViewById（R.id.textView）;
    切换按钮TB =（切换按钮）convertView
            .findViewById（R.id.toggleButton）;    tb.setOnCheckedChangeListener（新CompoundButton.OnCheckedChangeListener（）{        @覆盖
        公共无效onCheckedChanged（CompoundButton buttonView，
                布尔器isChecked）{            如果（器isChecked＆放大器;＆放大器;！rowItem.isSelected（））{                如果（selectedItemCounter＆GT; =极限）{
                    Toast.makeText（背景下，
                            不能更+ selectedItemCounter，
                            Toast.LENGTH_SHORT）.show（）;
                    buttonView.setChecked（假）;
                    返回;
                }                rowItem.setSelected（真）;
                selectedItemCounter ++;
            }否则如果（器isChecked＆放大器;！＆放大器; rowItem.isSelected（））{
                rowItem.setSelected（假）;
                selectedItemCounter--;
            }        }
    }）;    tv.setText（rowItem.getDevId（））;
    tb.setChecked（rowItem.isSelected（））;    返回convertView;
}@覆盖
公众诠释的getCount（）{
    返回rowItems.size（）;
}@覆盖
公共对象的getItem（INT位置）{
    返回rowItems.get（位置）;
}@覆盖
众长getItemId（INT位置）{
    返回rowItems.indexOf（的getItem（位置））;
}
}
 

努力提高我的code。与ViewHolder模式，但失败了。
如果任何人有更好的主意，请让我知道。

I have an ArrayList of Strings defined called names defined and I add to my ListView object as follows:

I create an Array Adapter and set multiple choice mode in both the Array Adapter and ListView object. This works great, I can scroll and pick multiple objects. But the problem is I want to force the user into being able to pick only 4 items from the ListView. How can I set a restriction?

adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_multiple_choice,names);
nameList.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
nameList.setAdapter(adapter);

解决方案

Try this:

public class AccountListAdapter extends BaseAdapter {

@SuppressWarnings("unused")
private final static String TAG = AccountListAdapter.class.getSimpleName();

private Context context;
private List<Account> rowItems;

private int selectedItemCounter = 0;

private final int limit;

public AccountListAdapter(Context context, List<Account> items, int limit) {
    this.context = context;
    this.rowItems = items;
    this.limit = limit;
}

public View getView(final int position, View convertView, ViewGroup parent) {

    LayoutInflater mInflater = (LayoutInflater) context
            .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

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

    convertView = mInflater.inflate(R.layout.account_selection_item, null);

    TextView tv = (TextView) convertView.findViewById(R.id.textView);
    ToggleButton tb = (ToggleButton) convertView
            .findViewById(R.id.toggleButton);

    tb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

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

            if (isChecked && !rowItem.isSelected()) {

                if (selectedItemCounter >= limit) {
                    Toast.makeText(context,
                            "can't be more" + selectedItemCounter,
                            Toast.LENGTH_SHORT).show();
                    buttonView.setChecked(false);
                    return;
                }

                rowItem.setSelected(true);
                selectedItemCounter++;
            } else if (!isChecked && rowItem.isSelected()) {
                rowItem.setSelected(false);
                selectedItemCounter--;
            }

        }
    });

    tv.setText(rowItem.getDevId());
    tb.setChecked(rowItem.isSelected());

    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));
}
}

tried to improve my code with ViewHolder pattern but failed. if anyone have better idea, please let me know.

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