Android(安卓)ExpandableListActivity 学习笔记

ExpandableListActivity:

An activity that displays an expandable list of items by binding to a data source implementing the ExpandableListAdapter, and exposes event handlers when the user selects an item.

即，可扩展的list，单击某个item后，又可显示一个子list。它的数据通过绑定到ExpandableListAdapter或者ExpandableListAdapter的子类上。

示例1—通过SimpelExpandableListAdapter绑定数据：

public class ExpandableList3 extends ExpandableListActivity { private static final String NAME = "NAME"; private static final String IS_EVEN = "IS_EVEN"; private ExpandableListAdapter mAdapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); List<Map<String, String>> groupData = new ArrayList<Map<String, String>>(); List<List<Map<String, String>>> childData = new ArrayList<List<Map<String, String>>>(); for (int i = 0; i < 20; i++) { Map<String, String> curGroupMap = new HashMap<String, String>(); groupData.add(curGroupMap); curGroupMap.put(NAME, "Group " + i); curGroupMap.put(IS_EVEN, (i % 2 == 0) ? "This group is even" : "This group is odd"); List<Map<String, String>> children = new ArrayList<Map<String, String>>(); for (int j = 0; j < 15; j++) { Map<String, String> curChildMap = new HashMap<String, String>(); children.add(curChildMap); curChildMap.put(NAME, "Child " + j); curChildMap.put(IS_EVEN, (j % 2 == 0) ? "This child is even" : "This child is odd"); } childData.add(children); } // Set up our adapter mAdapter = new SimpleExpandableListAdapter( this, groupData, // 存储父list的数据 android.R.layout.simple_expandable_list_item_2, //父list的现实方式 new String[] { NAME,IS_EVEN}, // 父list需要显示的数据 new int[] { android.R.id.text1,android.R.id.text2}, // 父list的数据绑定到的view childData, //子list的数据 android.R.layout.simple_expandable_list_item_2, new String[] { NAME, IS_EVEN }, new int[] { android.R.id.text1, android.R.id.text2 } ); setListAdapter(mAdapter); } }

注意：android.R.layout.simple_expandable_list_item_1：表示只显示一个TextView的数据，即R.id.text1

android.R.layout.simple_expandable_list_item_2：表示显示二个TextView的数据，即R.id.text1，R.id,text2

android.R.layout.simple_expandable_list_item_2.xml(在R.layout中)文件的布局如下：

<?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/text1" android:textSize="16sp" android:textStyle="bold" android:layout_width="fill_parent" android:layout_height="wrap_content"/> <TextView android:id="@+id/text2" android:textSize="16sp" android:layout_width="fill_parent" android:layout_height="wrap_content"/> </LinearLayout>

示例2—通过SimpleCussorTreeAdapter绑定数据：

public class ExpandableList2 extends ExpandableListActivity { private int mGroupIdColumnIndex; private String mPhoneNumberProjection[] = new String[] { People.Phones._ID, People.Phones.NUMBER }; private ExpandableListAdapter mAdapter; /* * CursorTreeAdapter's method. * Gets the Cursor for the children at the given group * / @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Query for people Cursor groupCursor = managedQuery(People.CONTENT_URI, new String[] {People._ID, People.NAME}, null, null, null); // Cache the ID column index mGroupIdColumnIndex = groupCursor.getColumnIndexOrThrow(People._ID); // Set up our adapter mAdapter = new MyExpandableListAdapter(groupCursor, this, android.R.layout.simple_expandable_list_item_1, android.R.layout.simple_expandable_list_item_1, new String[] {People.NAME}, // Name for group layouts new int[] {android.R.id.text1}, new String[] {People.NUMBER}, // Number for child layouts new int[] {android.R.id.text1}); setListAdapter(mAdapter); } public class MyExpandableListAdapter extends SimpleCursorTreeAdapter { public MyExpandableListAdapter(Cursor cursor, Context context, int groupLayout, int childLayout, String[] groupFrom, int[] groupTo, String[] childrenFrom, int[] childrenTo) { super(context, cursor, groupLayout, groupFrom, groupTo, childLayout, childrenFrom, childrenTo); } @Override protected Cursor getChildrenCursor(Cursor groupCursor) { // Given the group, we return a cursor for all the children within that group // Return a cursor that points to this contact's phone numbers Uri.Builder builder = People.CONTENT_URI.buildUpon(); ContentUris.appendId(builder, groupCursor.getLong(mGroupIdColumnIndex)); builder.appendEncodedPath(People.Phones.CONTENT_DIRECTORY); Uri phoneNumbersUri = builder.build(); // The returned Cursor MUST be managed by us, so we use Activity's helper // functionality to manage it for us. return managedQuery(phoneNumbersUri, mPhoneNumberProjection, null, null, null); } } }

示例3—通过BaseExpandableListAdapter绑定数据：

public class ExpandableList1 extends ExpandableListActivity { ExpandableListAdapter mAdapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Set up our adapter mAdapter = new MyExpandableListAdapter(); setListAdapter(mAdapter); // register context menu, when long click the item, it will show a dialog registerForContextMenu(getExpandableListView()); } @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { menu.setHeaderTitle("Sample menu"); menu.add(0, 0, 0, R.string.expandable_list_sample_action); } @Override public boolean onContextItemSelected(MenuItem item) { ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo(); String title = ((TextView) info.targetView).getText().toString(); int type = ExpandableListView.getPackedPositionType(info.packedPosition); if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) { int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition); Toast.makeText(this, title + ": Child " + childPos + " clicked in group " + groupPos, Toast.LENGTH_SHORT).show(); return true; } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) { int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); Toast.makeText(this, title + ": Group " + groupPos + " clicked", Toast.LENGTH_SHORT).show(); return true; } return false; } /** * A simple adapter which maintains an ArrayList of photo resource Ids. * Each photo is displayed as an image. This adapter supports clearing the * list of photos and adding a new photo. * */ public class MyExpandableListAdapter extends BaseExpandableListAdapter { // Sample data set. children[i] contains the children (String[]) for groups[i]. private String[] groups = { "People Names", "Dog Names", "Cat Names", "Fish Names" }; private String[][] children = { { "Arnold", "Barry", "Chuck", "David" }, { "Ace", "Bandit", "Cha-Cha", "Deuce" }, { "Fluffy", "Snuggles" }, { "Goldy", "Bubbles" } }; public Object getChild(int groupPosition, int childPosition) { return children[groupPosition][childPosition]; } public long getChildId(int groupPosition, int childPosition) { return childPosition; } public int getChildrenCount(int groupPosition) { return children[groupPosition].length; } public TextView getGenericView() { // Layout parameters for the ExpandableListView AbsListView.LayoutParams lp = new AbsListView.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, 64); TextView textView = new TextView(ExpandableList1.this); textView.setLayoutParams(lp); // Center the text vertically textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT); // Set the text starting position textView.setPadding(36, 0, 0, 0); return textView; } public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { TextView textView = getGenericView(); textView.setText(getChild(groupPosition, childPosition).toString()); return textView; } public Object getGroup(int groupPosition) { return groups[groupPosition]; } public int getGroupCount() { return groups.length; } public long getGroupId(int groupPosition) { return groupPosition; } public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { TextView textView = getGenericView(); textView.setText(getGroup(groupPosition).toString()); return textView; } public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } public boolean hasStableIds() { return true; } } }

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