UI(base)-5

ListView

ListView常用XML属性和说明：
android:choiceMode
设置ListView的选择行为
android:divider
设置List列表项的分割条
android:dividerHeight
设置分割条的高度
android:entries
指定一个数组资源，android将根据该数组资源生成ListView
android:footerDividersEnabled
如果设置为false，则不在footerView之前绘制分割条。
android:headerDividersEnabled
如果设置为false，则不在headerView之后绘制分割条。

创建一个ListView
方法1：示例代码

<ListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:entries="@array/Stars"
    android:divider="#f00"//指定分割线颜色
    android:divider="1px"//分割线高度
    android:scrollbar="none"//隐藏滚动条
    android:overScrollMode="never"//取消滑动过头提醒

    />
在Values文件夹下创建arrays.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="Stars">
        <item>Joe</item>
        <item>Martin</item>
        <item>Kobe</item>
        <item>James</item>
        <item>oven</item>
        <item>Joe2</item>
        <item>Martin3</item>
        <item>Kobe4</item>
        <item>James5</item>
        <item>oven6</item>
</string-array>


</resources>

方法二：用java代码创建ListView
示例代码：

public class MainActivity extends AppCompatActivity {
        String[] strings = {"Joe","Kobe","curry","James","harde","Martin"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView) findViewById(R.id.demoListView);

        ArrayAdapter<String> adapter1 = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, text1,strings);
        listView.setAdapter(adapter1);
    }
}

ListView SimpleAdapter:简单适配器
通过simpleAdapter 我们很容易实现在ListView的每一项布局里面实现多个TextView，并且显示一些额外的UI控件,比如图片。。。

构造方法：

SimpleAdapter(Context context,List<? extends Map<String,?>> data, int resource,String[] from, int[] to)

context:上下文
data:数据源，是一个Map对象列表
resource:每一项的布局资源ID
from ：在Map对象中存储的Key
to:每一项布局资源中需要显示文本的TextView的ID数组。

示例代码：
java代码

public class MainActivity extends AppCompatActivity {
       // String[] strings = {"Joe","Kobe","curry","James","harde","Martin"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView) findViewById(R.id.demoListView);
//
//        ArrayAdapter<String> adapter1 = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, text1,strings);
//        listView.setAdapter(adapter1);
        List<Map<String ,?>> dataList = new ArrayList<>();
         for (int i = 0;i < 50; i++){
             Map<String,String> map = new HashMap<>();
             map.put("name","张三"+ i);
             map.put("sex",i%2==0?"男":"女");
             map.put("age",10+i +"");
             dataList.add(map);
         }
        String[] from ={"name","age","sex"};
        int[] to = {R.id.TV_name,R.id.TV_age,R.id.TV_sex};

        SimpleAdapter simpleAdapter = new SimpleAdapter(this,dataList,R.layout.item_user_ifo,from,to);
          listView.setAdapter(simpleAdapter);

对应的XML文件: item_user_ifo.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ImageView
        android:src="@drawable/home"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/TV_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/TV_age"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/TV_sex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

simpleAdapte
弊端:不能根据我们的逻辑给其他的非TextView的控件设置它所想要的显示逻辑。对于复杂的ListView列表，建议使用BaseAdapte定义我们逻辑需要的适配器。

ListView BaseAdapter:简单适配器
baseadapter是一个抽象类
我们可以通过继承baseadapter实现它的抽象方法，来定义我们的adapter.
代码示例:

public class BaseAdaptertest extends Activity{
    List<String> dataList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.baseadapter);

        ListView listView = (ListView) findViewById(R.id.baseadapter_list);
       dataList = new ArrayList<>();
        for (int i = 0; i<50;i++){
            dataList.add("Joe"+1);
        }
           UserInforListadapter  userInforListadapter = new UserInforListadapter();
            listView.setAdapter(userInforListadapter);
    }
    class UserInforListadapter extends BaseAdapter{

        @Override
        public int getCount() {
            return dataList.size();
        }

        @Override
        public Object getItem(int position) {
            return dataList.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View itemRootView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user_ifo,null);
            TextView tvName = (TextView) itemRootView.findViewById(R.id.TV_name);
            tvName.setText(dataList.get(position));
            return itemRootView ;
        }
    }
}