Android中ListView的用法

Android中ListView的用法,原文如下:

ListView是一個經常用到的控件,ListView裡面的每個子項Item可以使一個字符串,也可以是一個組合控件。先說說ListView的實現:

1.準備ListView要顯示的數據 ;

2.使用 一維或多維 動態數組 保存數據;

2.構建適配器 , 簡單地來說, 適配器就是 Item數組 , 動態數組 有多少元素就生成多少個Item;

3.把 適配器 添加到ListView,並顯示出來。

接下來,看看本文代碼所實現的ListView:

 

接下來,就開始UI的XML代碼:

main.xml代碼如下,很簡單,也不需要多做解釋瞭:

[plain]
<?xmlversion="1.0"encoding="utf-8"?> 
 
<LinearLayout 
 
        android:id="@+id/LinearLayout01" 
 
        android:layout_width="fill_parent" 
 
        android:layout_height="fill_parent" 
 
        xmlns:android="http://schemas.android.com/apk/res/android"> 
 
          
 
        <ListViewandroid:layout_width="wrap_content" 
 
                 android:layout_height="wrap_content" 
 
                 android:id="@+id/MyListView"> 
 
        </ListView> 
 
</LinearLayout> 

<?xmlversion="1.0"encoding="utf-8"?>

<LinearLayout

        android:id="@+id/LinearLayout01"

        android:layout_width="fill_parent"

        android:layout_height="fill_parent"

        xmlns:android="http://schemas.android.com/apk/res/android">

        

        <ListViewandroid:layout_width="wrap_content"

                 android:layout_height="wrap_content"

                 android:id="@+id/MyListView">

        </ListView>

</LinearLayout>

 

 

佈局文件:my_listitem.xml的代碼如下,my_listitem.xml用於設計ListView的Item:

[html]
<?xmlversionxmlversion="1.0"encoding="utf-8"?> 
 
<LinearLayout 
 
        android:layout_width="fill_parent" 
 
        xmlns:android="http://schemas.android.com/apk/res/android" 
 
        android:orientation="vertical" 
 
        android:layout_height="wrap_content" 
 
        android:id="@+id/MyListItem" 
 
        android:paddingBottom="3dip" 
 
        android:paddingLeft="10dip"> 
 
        <TextView 
 
               android:layout_height="wrap_content" 
 
               android:layout_width="fill_parent" 
 
               android:id="@+id/ItemTitle" 
 
               android:textSize="30dip"> 
 
        </TextView> 
 
        <TextView 
 
               android:layout_height="wrap_content" 
 
               android:layout_width="fill_parent" 
 
               android:id="@+id/ItemText"> 
 
        </TextView> 
 
</LinearLayout> 

<?xmlversion="1.0"encoding="utf-8"?>

<LinearLayout

        android:layout_width="fill_parent"

        xmlns:android="http://schemas.android.com/apk/res/android"

        android:orientation="vertical"

        android:layout_height="wrap_content"

        android:id="@+id/MyListItem"

        android:paddingBottom="3dip"

        android:paddingLeft="10dip">

        <TextView

               android:layout_height="wrap_content"

               android:layout_width="fill_parent"

               android:id="@+id/ItemTitle"

               android:textSize="30dip">

        </TextView>

        <TextView

               android:layout_height="wrap_content"

               android:layout_width="fill_parent"

               android:id="@+id/ItemText">

        </TextView>

</LinearLayout>
 

  

解釋一下,裡面用到的一些屬性:

1.paddingBottom="3dip",Layout往底部留出3個像素的空白區域

2.paddingLeft="10dip",Layout往左邊留出10個像素的空白區域

3.textSize="30dip",TextView的字體為30個像素那麼大。

最後就是JAVA的源代碼:

[javascript]
public void onCreate(Bundle savedInstanceState) { 
 
    super.onCreate(savedInstanceState); 
 
    setContentView(R.layout.main); 
 
    //綁定XML中的ListView,作為Item的容器  
 
    ListView list = (ListView) findViewById(R.id.MyListView); 
 
      
 
    //生成動態數組,並且轉載數據  
 
    ArrayList<HashMap<String, String>> mylist =new ArrayList<HashMap<String, String>>(); 
 
    for(inti=0;i<30;i++) 
 
    { 
 
        HashMap<String, String> map = newHashMap<String, String>(); 
 
        map.put("ItemTitle","This is Title….."); 
 
        map.put("ItemText","This is text….."); 
 
        mylist.add(map); 
 
    } 
 
    //生成適配器,數組===》ListItem  
 
    SimpleAdapter mSchedule =new SimpleAdapter(this,//沒什麼解釋  
 
                                               mylist,//數據來源   
 
                                               R.layout.my_listitem,//ListItem的XML實現  
 
                                                 
 
                                               //動態數組與ListItem對應的子項          
 
                                               new String[] {"ItemTitle","ItemText"},  
 
                                                 
 
                                               //ListItem的XML文件裡面的兩個TextView ID  
 
                                               new int[] {R.id.ItemTitle,R.id.ItemText}); 
 
    //添加並且顯示  
 
    list.setAdapter(mSchedule); 
 

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    //綁定XML中的ListView,作為Item的容器

    ListView list = (ListView) findViewById(R.id.MyListView);

    

    //生成動態數組,並且轉載數據

    ArrayList<HashMap<String, String>> mylist =new ArrayList<HashMap<String, String>>();

    for(inti=0;i<30;i++)

    {

        HashMap<String, String> map = newHashMap<String, String>();

        map.put("ItemTitle","This is Title…..");

        map.put("ItemText","This is text…..");

        mylist.add(map);

    }

    //生成適配器,數組===》ListItem

    SimpleAdapter mSchedule =new SimpleAdapter(this,//沒什麼解釋

                                               mylist,//數據來源

                                               R.layout.my_listitem,//ListItem的XML實現

                                               

                                               //動態數組與ListItem對應的子項       

                                               new String[] {"ItemTitle","ItemText"},

                                               

                                               //ListItem的XML文件裡面的兩個TextView ID

                                               new int[] {R.id.ItemTitle,R.id.ItemText});

    //添加並且顯示

    list.setAdapter(mSchedule);

}
 

 

//數據庫獲取數據

[java]
DBHelper helper=new DBHelper(this); 
Cursor c=helper.query(); 
           
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>(); 
int i=0; 
while (c.moveToNext()) { 
    HashMap<String, String> map = new HashMap<String, String>(); 
    map.put("title",c.getString(c.getColumnIndex("Title"))); 
    map.put("date",c.getString(c.getColumnIndex("Date"))); 
    mylist.add(map); 
    i++; 

String[] from={"title","date"}; 
int[] to={R.id.ItemTitle,R.id.ItemDate}; 
SimpleAdapter ada=new SimpleAdapter(this,mylist,R.layout.listitem,from,to); 
 
ListView list = (ListView) findViewById(R.id.MyListView); 
list.setAdapter(ada); 

DBHelper helper=new DBHelper(this);
Cursor c=helper.query();
      
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
int i=0;
while (c.moveToNext()) {
 HashMap<String, String> map = new HashMap<String, String>();
 map.put("title",c.getString(c.getColumnIndex("Title")));
 map.put("date",c.getString(c.getColumnIndex("Date")));
 mylist.add(map);
 i++;
}
String[] from={"title","date"};
int[] to={R.id.ItemTitle,R.id.ItemDate};
SimpleAdapter ada=new SimpleAdapter(this,mylist,R.layout.listitem,from,to);

ListView list = (ListView) findViewById(R.id.MyListView);
list.setAdapter(ada);
 

 

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