带复选框的 Android ListView：如何捕获选中的项目？

Question

我必须使用 CheckBoxes 执行 ListView ，然后在用户按下按钮时显示选中和未选中的项目。问题是我不知道该怎么做，我设法用以下代码显示 ListView 和 CheckBox ：

package guestCheckBox.com;

import java.net.URL;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class GuestCheckBox extends Activity {
    private ListView lView;             
    ArrayList<String> guest= new ArrayList <String>();

    @Override
    public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);  
    lView = (ListView) findViewById(R.id.ListView01);

    try{

        URL url = new URL(
        "http://tanjungrhu.jigsy.com/files/documents/Check.xml");
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse(new InputSource(url.openStream()));
        doc.getDocumentElement().normalize();

        NodeList words = doc.getElementsByTagName("Guest");

        for(int i=0;i<words.getLength();i++){
            Node node = words.item(i);

            Element fstElmnt = (Element) node;
            NodeList NameList = fstElmnt.getElementsByTagName("Name");
            Element NameElement = (Element) NameList.item(0);
            NameList = NameElement.getChildNodes();
            guest.add((((Node) NameList.item(0)).getNodeValue()));
        }

}
catch (Throwable t){
    Toast.makeText(this, "Exeption:" + t.toString(), 2000).show();
}

//Set option as Multiple Choice. So that user can able to select more the one option from list
    lView.setAdapter(new ArrayAdapter<String>(this,
    android.R.layout.simple_list_item_multiple_choice, guest));
    lView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    }
}

这里是我的 main.xml< /code>：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"  />

<ListView 
    android:id="@+id/ListView01" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent">
</ListView>

</LinearLayout>

有人会告诉我如何执行按钮以及当用户按下该按钮时如何显示选中和未选中的项目吗？

Answer 1

我不完全明白问题是什么，但我可以为您提供 ListView 的一个有用的扩展，它可以帮助您操作字符串数据（设置\获取检查值）：

public class MultipleChoiceListView extends ListView {

public MultipleChoiceListView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

public MultipleChoiceListView(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public MultipleChoiceListView(Context context) {
    super(context);
}

@Override
public void setAdapter(ListAdapter adapter) {
    throw new RuntimeException(
        "This component doesn't support custom adapter. Use setData method to supply some data to show.");
}

/**
 * Sets the data that should be displayed for choosing
 * 
 * @param data List<String>
 */
public void setData(List<String> data) {
    super.setAdapter(new ArrayAdapter<String>(getContext(), android.R.layout.simple_list_item_multiple_choice, data));
    super.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
}

/**
 * Sets the data that should be choosen by default
 * 
 * @param checkedData List<String>
 */
public void setCheckedData(List<String> checkedData) {
    for (int index = 0; index < getCount(); index++) {
        if (checkedData.contains(getItemAtPosition(index))) {
            setItemChecked(index, true);
        }
    }
}

/**
 * Returns checked by the user data passed in {@link #setData(List)}
 * 
 * @return List<String>
 */
public List<String> getCheckedData() {
    SparseBooleanArray checked = getCheckedItemPositions();
    List<String> checkedResult = new ArrayList<String>();

    for (int i = 0; i < checked.size(); i++) {
        if (checked.valueAt(i)) {
            checkedResult.add(getAdapter().getItem(checked.keyAt(i)).toString());
        }
    }
    return checkedResult;
}

}

使用示例：

    private void initListMultiple() {
    String[] data = new String[] {"first", "second", "third", "forth"};
    String[] checkedData = new String[] {"second", "forth"};

    multipleChoiceListView.setData(Arrays.asList(data));
    multipleChoiceListView.setCheckedData(Arrays.asList(checkedData));
}

private void onTestListButtonClicked(View view) {
    listResultTextView.setText(Arrays.toString(listView.getCheckedData().toArray()));
}