【转】Sections Headers for Android ListViews

下面的文章是我在搜索SectionsHeaders for Android 的时候 StackOverflow上边的好几个答案都说到的一篇文章（相比应该很经典）。

原文地址应该是这里：http://thebogles.com/blog/2010/02/section-headers-for-android-listviews/ （可惜我打不开，原文具体内容不得而知，遗憾）

下面是我从http://bbs.hidroid.net/thread-1069-1-1.html这里摘录的：

When building the Android version of the iLike Concert app, I wanted to have day headers for the concert list.
This was easy on the iPhone; sections are built into the oUITableView class.  
Surprisingly, the ListView class in Android doesn't provide any corresponding functionality, as of Android 2.1.
Jeff Sharkey's SeparatedListAdapterprovides one way to get this functionality; it glues together a numberof individual adapters for each section into an overall list.
In my case, I had one SimpleCursorAdapter for the whole list, so I didn't want to break it into individual adapters just to displaysections.
Instead, I made the header a part of the list cell layout, and hid the header on the rows where I didn't want to display it. The headers look as follows:

My layout was like as follows; note the use of the explicit background color and textColorHighlight in the date header to preventit from appearing as selected.

<?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"> 
  <TextView android:id="@+id/date_header" 
                        android:textSize="20px" 
                        android:textStyle="bold" 
                        android:textColor="#000" 
                        android:textColorHighlight="#000" 
                        android:background="#DDD" 
                        android:visibility="gone" 
                        android:layout_width="fill_parent" 
                        android:layout_height="wrap_content"/> 
  <LinearLayout 
          xmlns:android="http://schemas.android.com/apk/res/android" 
          android:layout_width="fill_parent" 
          android:layout_height="77px" 
          android:gravity="center_vertical" 
          android:orientation="horizontal"> 
        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="100px" android:layout_height="75px" android:gravity="center_vertical|center_horizontal" android:orientation="horizontal"> 
          <ImageView android:id="@+id/image" android:layout_width="75px" android:layout_height="75px"/> 
        </LinearLayout> 
        <LinearLayout 
                xmlns:android="http://schemas.android.com/apk/res/android" 
                android:layout_width="fill_parent" 
                android:layout_height="wrap_content" 
                android:gravity="center_vertical" 
                android:orientation="vertical"> 
          <TextView android:id="@+id/title" 
                                android:textSize="20px" 
                                android:textStyle="bold" 
                                android:layout_width="fill_parent" 
                                android:layout_height="wrap_content"/> 
          <TextView android:id="@+id/description" 
                                android:textSize="14px" 
                                android:layout_width="fill_parent" 
                                android:layout_height="wrap_content"/> 
        </LinearLayout> 
  </LinearLayout> 
</LinearLayout>

The view binder assumes a function called isHeaderVisible to decide whether the header should be visible for the current row in the cursor;implement as appropriate for your application. (For example, ourapplication displays a header whenever the date of the current row isdifferent from the previous row.)

SimpleCursorAdapter listAdapter = new SimpleCursorAdapter(mContext, 
                                R.layout.list_item, 
                                mEventsCursor, 
                                new String[] {"artist_75x75_image_url", "artist_name", "venue_name", "event_date_string" }, 
                                new int[] {R.id.image, R.id.title, R.id.description, R.id.date_header }); 
        final int nDateIndex = mEventsCursor.getColumnIndex("event_date_string"); 
        listAdapter.setViewBinder( new SimpleCursorAdapter.ViewBinder() 
                { 
                        public boolean setViewValue(View view, Cursor cursor, int 
columnIndex) 
                        { 
                                  if (columnIndex == nDateIndex) { 
                                        if (isHeaderVisible(cursor)) { 
                                                view.setVisibility(View.VISIBLE); 
                                                prevDate = dateString; 
                                                ((TextView) view).setText(dateString); 
                                        } else { 
                                                ((TextView) view).setText(""); 
                                                view.setVisibility(View.GONE); 
                                        } 
                                        return true; 
                                } 
                                return false; 
                        } 
                });