ListView的使用总结
基本使用：
步骤：在布局文件中定义一个ListView控件-在活动中获得ListView的实例-获得适配器adapter的实例并且传入三个参数-把适配器对象传递给listview实例
public class MainActivity extends Activity{
ListView contactsView;
ArrayAdapter<String> adapter;
List<String> contactsList=new ArrayList<String>();
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactsView=(ListView)findViewById(R.id.contactsView);
adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,contactsList);
contactsView.setAdapter(adapter);
readContacts();
}
public void readContacts(){
Cursor cursor=null;
try{
cursor=getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null);
while(cursor.moveToNext()){
String name=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
String number=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
contactsList.add(name+"/n"+number);
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(cursor!=null){
cursor.close();
}
}
}
}
自定义的ListView的使用
步骤：自定义适配器适配类型-为每一个子项制定自定义布局（item——layout）-创建自定义的适配器，将每一个子项的内容指定给布局控件-
-获得listview 的实例以及一个容纳所有子项的list实例和适配器实例-把适配器传入布局
例如一个水果自定义listview
public class Fruit(){
private String name;
private int ImageId;
public Fruit(String name,int ImageId){
this.name=name;
this.ImageId=ImageId;
}
public String getName(){
return name;
}
public int ImageId(){
return ImageId;
}
}
fruit_item.xml
...
<ImageView
.../>
<TextView
.../>
...
public class FruitAdapter extends ArrrayAdapter(Fruit){
private int resourceId;
public FruitAdapter(Context context,int textViewResourceId,List<Fruit>objects){
super(context,textViewResourceId,objects);
resourceId=textViewResourceId;
}
public View getView(int position,View convertView,ViewGroup parent){
Fruit fruit=getItem(position);
View view=LayoutInflater.from(getContext()).inflate(resourceId,null);
ImageView fruitImage=(ImageView) view.findViewById(R.id.fruit_image);
TextView fruitName=(TextView) view.findViewById(R.id.fruit_name);
fruitImage.setImageResource(fruit.getImageId());
fruiName.setText(fruit.getName());
return view;
}
}
mainactivity
....
gridview的使用
几个属性：
android:numColumns="auto_fit" --------列数设置为自动
android:columnWidth="90dp"，----------每列的宽度，也就是Item的宽度
android:stretchMode="columnWidth"------缩放与列宽大小同步
android:verticalSpacing="10dp"----------垂直边距
android:horizontalSpacing="10dp"-------水平边距
public void mainactivity extends Activity{
private GridView gv;
private List<Map<String,Objects>> data_list=new ArrayList<Map<String,Objects>>();
private SimpleAdapter<map<String,Objects>> adapter;
private int[] image={R.id...,.....,......};
private String[] name={.....};
public void onCreate(Bundle savedInstanceState){
super.(savedInstanceState);
setContentView(R.layout.test);
gv=(GridView)findViewById(R.id.gridview);
getdata();
String[] from={"image","text"};
int[] to={R.id.image,R.id.text};
adapter=new SimpleAdapter<map<String,Objects>>(mainactivity.this,data_list.R.layout.item,from,to);
gv.setAdapter(adapter);
}
public List<Map<String,Objects>> getdata(){
for(int i=;i<image.length;i++){
Map<String,objects> map=new HashMap<String,Objects>();
map.put("image",image[i]);
map.put("text",name[i]);
data_list.add(map);
}
return data_list;
}
}
补充关于hashmap：
这里使用hashmap就相当于在自定义的listview中的自定义泛型 fruit目的都是为了能够容纳一对对的数据集合
Map<String, Object> map = new HashMap<String, Object>();
map.put("image", icon[i]);
map.put("text", iconName[i]);
data_list.add(map);此处的map就是一对数据的集合