Android 为ListView添加分段标头的方法

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"  android:id="@+id/header"  style="@android:style/TextAppearance.Small"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:background="#0000ff" />

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent" >  <ListView    android:id="@android:id/list"    android:layout_width="fill_parent"    android:layout_height="fill_parent" />  <include layout="@layout/header" /></FrameLayout>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:orientation="vertical" >  <include layout="@layout/header" />  <TextView    android:id="@+id/label"    style="@android:style/TextAppearance.Large"    android:layout_width="fill_parent"    android:layout_height="wrap_content" /></LinearLayout>

public class SectionAdapter extends ArrayAdapter<String> { private Activity activity; public SectionAdapter(Activity activity, String[] objects) {  super(activity, R.layout.list_item, R.id.label, objects);//为自定义视图指定XML布局文件  this.activity = activity; } @Override public View getView(int position, View view, ViewGroup parent) {  if (view == null) {   view = activity.getLayoutInflater().inflate(R.layout.list_item,     parent, false);  }  TextView header = (TextView) view.findViewById(R.id.header);  String label = getItem(position);  if (position == 0//检查列表项起始字母是否发生了改变，如果发生改变，该列表项就是分段中的第一项，修改分段标头的内容并显示该分段标头,否则隐藏    || getItem(position - 1).charAt(0) != label.charAt(0)) {   header.setVisibility(View.VISIBLE);   header.setText(label.substring(0, 1));  } else {   header.setVisibility(View.GONE);//隐藏分段标头  }  return super.getView(position, view, parent); }}

public class Hack26Activity extends ListActivity {  private TextView topHeader;//用于访问分段标头  private int topVisiblePosition = -1;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.list);    topHeader = (TextView) findViewById(R.id.header);    setListAdapter(new SectionAdapter(this, Countries.COUNTRIES));    //设置滚动监听器，当用户滚动列表时，检查位置是否发生了变化，如果改变，调用setTopHeader更新悬浮的分段标头，当列表第一次显示时，确保根据第一个列表项初始化分段标头    getListView().setOnScrollListener(        new AbsListView.OnScrollListener() {          @Override          public void onScrollStateChanged(AbsListView view,                           int scrollState) {            // Empty.          }          @Override          public void onScroll(AbsListView view, int firstVisibleItem,                     int visibleItemCount, int totalItemCount) {            if (firstVisibleItem != topVisiblePosition) {              topVisiblePosition = firstVisibleItem;              setTopHeader(firstVisibleItem);            }          }        });    setTopHeader(0);  }  private void setTopHeader(int pos) {    final String text = Countries.COUNTRIES[pos].substring(0, 1);    topHeader.setText(text);//更新文本内容  }}