[置顶] 安卓UI组件之ListView详解

ListView是很常见的一个UI组件，在许多App中都很常用，其意思就是可滚动的列表，使用ListView必须使用Adapter（适配器），常用的适配器友谊ArrayAdapter,SimpleAdapter,BaseAdapter.

ListView一些特殊的属性是：

android:divider="@drawable/red"//每个列表项之间的分割线
android:entries="@drawable/books"//列表项显示的数据

布局代码示例：

第一我们使用SimpleAdapter来写一个ListView：

public class SimpleAdapter extends Activity{private String[] names =new String[]{"nick","lebron","kobe","kevin"};private int[] imgsIds[] =new Int[] {R.drawable.1,R.drawable.2,R.drawable.3,R.drawable.4};@Overridepublic void onCreate(Bundle savedInsatnceState){super.onCreate(savedInsatnceState);setTitle("simpleadapter");setContentView(R.layout.main);List<Map><String,Object> list=new ArrayList<Map><String,Object>（）;//创建动态数组ArrayListfor(int i=0;i<names.length;i++){Map<String,Object> map=new HashMap=<String,Object>;map.put("name",names[i]);map.put("headerImg",imgsIds[i]);list.add(map);}SimpleAdapter adapter=new SimpleAdaper(this,list,R.layout.main,new String[]{"name","headerImg"},new int[]{R.id.name,R.id.headerImg});ListView list=(ListView)findViewById(R.id.mylist);list.setAdaper(adapter);}}

*注释*
SimpleAdapter是另一种常见的adapter类型，其有五个参数
1：Activity.this
2：传入的数据
3：数据传入的界面
4：数据中Map类型数据的String 类的key
5：穿入界面的组件的Id
**

第二种我们使用ArrayAdapter：代码不详解，只是重写Adapter：

String[] str={"china","america","japan"};List list=new ArrayList<String>();for(int i=0;i<str.length;i++){list.add(str[i]);}ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,R.layout.simple_list_item2,list);

*注释*

第三个属性指定要显示每一个ListItem的风格：

ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,R.layout.simple_list_item1,list);：普通文本框
ArrayAdapter<String> adapter=new ArrayAdapetr<String>(this,R.layout.simple_list_multiple_choice);：多选框
ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,R.layout.simple_list_single_choice);：单选框

另外，ListView还有一个拓展组件ExpandableListView，就是可拓展的列表，但是他的适配器必须使用ExpandableAdapter：

public class ExpandableListViewTest extends Activity{@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);//创建一个BaseExpandableListAdapter对象ExpandableListAdapter adapter = new BaseExpandableListAdapter(){int[] logos = new int[]{R.drawable.p,R.drawable.z,R.drawable.t}; private String[] armTypes = new String[]{ "神族兵种", "虫族兵种", "人族兵种"};private String[][] arms = new String[][]{{ "狂战士", "龙骑士", "黑暗圣堂", "电兵" },{ "小狗", "刺蛇", "飞龙", "自爆飞机" },{ "机枪兵", "护士MM" , "幽灵" }};//获取指定组位置、指定子列表项处的子列表项数据@Overridepublic Object getChild(int groupPosition, int childPosition){return arms[groupPosition][childPosition];}@Overridepublic long getChildId(int groupPosition, int childPosition){return childPosition;}@Overridepublic int getChildrenCount(int groupPosition){return arms[groupPosition].length;}private TextView getTextView(){AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 64);TextView textView = new TextView(ExpandableListViewTest.this);textView.setLayoutParams(lp);textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);textView.setPadding(36, 0, 0, 0);textView.setTextSize(20);return textView;}//该方法决定每个子选项的外观@Overridepublic View getChildView(int groupPosition, int childPosition,boolean isLastChild, View convertView, ViewGroup parent){TextView textView = getTextView();textView.setText(getChild(groupPosition, childPosition).toString());return textView;}//获取指定组位置处的组数据@Overridepublic Object getGroup(int groupPosition){return armTypes[groupPosition];}@Overridepublic int getGroupCount(){return armTypes.length;}@Overridepublic long getGroupId(int groupPosition){return groupPosition;}//该方法决定每个组选项的外观@Overridepublic View getGroupView(int groupPosition, boolean isExpanded,View convertView, ViewGroup parent){LinearLayout ll = new LinearLayout(ExpandableListViewTest.this);ll.setOrientation(0);ImageView logo = new ImageView(ExpandableListViewTest.this);logo.setImageResource(logos[groupPosition]);ll.addView(logo);TextView textView = getTextView();textView.setText(getGroup(groupPosition).toString());ll.addView(textView);return ll;}@Overridepublic boolean isChildSelectable(int groupPosition, int childPosition){return true;}@Overridepublic boolean hasStableIds(){return true;}};ExpandableListView expandListView = (ExpandableListView)findViewById(R.id.list);expandListView.setAdapter(adapter);}}

使用ExpandableAdapter，我们重新首先重写其中的一些方法，每一个getGroupView就是显示的每一个ListGroupItem（列表项），其中重写的getGroupCount方法放回的就是有多少列表项，而getChildView（）就是显示每一个子列表项，同理getChildCount（）每一个列表项里面的子列表项个数。

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